worked on getting writing desk model to match legacy

BUILDING.txt

@@ -0,0 +1,113 @@
+Rivencraft Build Instructions
+============================
+
+These instructions apply when source code, models, textures, data, or other
+resources have been changed.
+
+Requirements
+------------
+
+- Java 21 JDK
+- A working Gradle wrapper
+- The project dependencies available in the Gradle cache, or network access
+  for Gradle to download them
+
+The project targets Minecraft 1.21.1 and NeoForge 21.1.251.
+
+1. Open the project directory
+--------------------------------
+
+    cd /path/to/rivencraft
+
+2. Check the changed files
+--------------------------
+
+Confirm that model, texture, and other resource files are inside
+`src/main/resources`. Java source files belong under `src/main/java`.
+
+For example, block models are normally stored under:
+
+    src/main/resources/assets/rivencraft/models/block/
+
+Resource files placed under `src/main/resources` are automatically included in
+the finished mod JAR by Gradle.
+
+3. Update the version when appropriate
+---------------------------------------
+
+Rivencraft uses the version format `x.y.z.b`:
+
+- `x`: major release
+- `y`: milestone completion
+- `z`: release slice
+- `b`: bug fixes and additional work within that slice
+
+Edit `mod_version` in `gradle.properties` before creating a new release. Do
+not reuse a version that has already been published.
+
+4. Build the mod
+----------------
+
+From the project directory, run:
+
+    ./gradlew build --offline
+
+If the required dependencies are not cached locally, remove `--offline`:
+
+    ./gradlew build
+
+On systems using mise-managed Java and Gradle, use:
+
+    mise exec -- ./gradlew build --offline
+
+5. Run the automated tests
+--------------------------
+
+To build and run the GameTest suite:
+
+    ./gradlew build runGameTestServer --offline
+
+Or, with mise:
+
+    mise exec -- ./gradlew build runGameTestServer --offline
+
+All required GameTests should pass before distributing a build.
+
+6. Locate and inspect the JAR
+-----------------------------
+
+Build outputs are written to:
+
+    build/libs/
+
+The filename uses the configured version, for example:
+
+    build/libs/rivencraft-0.3.6.9.jar
+
+To verify that changed resource files are packaged:
+
+    unzip -l build/libs/rivencraft-VERSION.jar | rg 'models|textures|data'
+
+Replace `VERSION` with the actual version number.
+
+To create a checksum for distribution:
+
+    sha256sum build/libs/rivencraft-VERSION.jar
+
+7. Stop the Gradle daemon when finished
+----------------------------------------
+
+This is optional, but useful after a long test run:
+
+    ./gradlew --stop
+
+Release checklist
+-----------------
+
+- Confirm the version was incremented when required.
+- Confirm the build completed successfully.
+- Confirm all required GameTests passed.
+- Confirm changed resources are present in the JAR.
+- Generate and record the SHA-256 checksum.
+- Test the JAR in the target Minecraft 1.21.1 NeoForge instance.
+- Publish the JAR only after client-side testing is complete.

NOTICE

@@ -6,6 +6,16 @@ It is not an official release of Mystcraft.
 Mystcraft Legacy source: https://github.com/Mystcraft/Mystcraft-Legacy
 Mystcraft Legacy copyright: XCompWiz and contributors
 Mystcraft Legacy license: GNU Lesser General Public License version 3
+The animated ink-vial item texture in this project is copied from Mystcraft
+Legacy's assets/mystcraft/textures/items/ink_vial.png under that license.
+The Notebook page atlas is copied from Legacy's assets/mystcraft/gui/bookui_pagel.png
+under the same license.
+The Writing Desk item texture is copied from Legacy's
+assets/mystcraft/textures/items/writingdesk.png under the same license.
+The Writing Desk block texture is copied from Legacy's
+assets/mystcraft/textures/entity/desk.png under the same license.
+The Writing Desk GUI atlas is copied from Legacy's assets/mystcraft/gui/writingdesk.png
+under the same license; desk wood and inlay textures are cropped from desk.png.
 
 The initial build layout is derived from the official NeoForge 1.21.1
 ModDevGradle MDK: https://github.com/NeoForgeMDKs/MDK-1.21.1-ModDevGradle

README.md

@@ -4,10 +4,60 @@ Rivencraft is a clean, incremental port of the ideas and gameplay of
 [Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) to Minecraft
 1.21.1 on NeoForge.
 
-The bootstrap and books/linking milestones are complete. The project currently
+The bootstrap, books/linking, and Ages milestones are complete. Milestone 4 is
-provides functional Linking Books and randomly seeded, persistent vanilla-like
+building the writing system on a data-pack symbol catalog and persistent
-Ages created from page-free Descriptive Books. Symbols, instability, and the
+ordered-writing model. The project currently provides functional Linking Books
-full writing mechanics have not been ported yet.
+and randomly seeded, persistent vanilla-like Ages created from page-free
+Descriptive Books. Instability and full symbol-to-world grammar interpretation
+have not been ported yet.
+
+Milestone 4 now includes stackable blank Pages plus server-created symbol,
+unresolved-symbol, and baseline link-panel states. Page visuals follow the
+legacy runtime-composition rules. Craft an Ink Vial from two black dye, a glass
+bottle, and a water bucket; the bucket is returned. Hold vanilla paper in one
+hand and use the Ink Vial in the other to prepare a baseline Link Panel Page.
+Each vial holds 16 ink units, and the default link-panel cost is two units.
+The spent vial returns a glass bottle. Server owners can adjust the symbol-copy
+and link-panel costs in the `writing` section of `rivencraft-server.toml`.
+The Writing Desk can copy a selected written page from its collection tabs.
+The Writing Desk is now craftable from planks, a glass bottle, and a feather.
+It occupies two adjacent blocks, with one shared inventory; loaded paper and
+the selected page appear on its Legacy-inspired model.
+Desks placed before 0.3.6.1 keep their old one-block footprint until broken
+and placed again; leave an adjacent space when replacing one.
+Its 88 collection tabs, paper input, ink vial input, empty glass-bottle return,
+16-unit ink meter, and inventory persist
+through world saves; breaking it drops stored contents. The desk screen is a
+functional foundation using Legacy's original desk and scrollbar textures.
+Four tabs are visible at once; the controls above and below them move by four
+(1–4, 5–8, through 85–88). Each viewer can browse a different group. Existing
+four-tab desks retain their collections and supplies when upgraded.
+With a notebook selected, pick up a Page from your inventory and click an empty
+position on the left surface to store one page there. Clear search/filter/sort
+and turn off `ALL` to place pages at specific positions; occupied positions are
+never overwritten. A notebook tab exposes all 27 notebook positions (scroll to
+reach the rest); a loose-page tab exposes only its one occupied position.
+Empty tabs have no page storage until a notebook or page is put in the tab slot.
+Click a page on the desk surface to select it for copying. Drag a page from one
+notebook position to an empty position to move it, or onto another page to swap
+their positions. This also works between notebooks shown in the `ALL` view.
+Drag a page out of the panel to turn it back into an item. Drop it over a player
+inventory slot or desk tab to place it there; a tab with a notebook adds it to
+the first open position. Dropping elsewhere leaves the page on the cursor for
+normal inventory placement. The source notebook or tab loses the page only after
+a valid drop.
+Put vanilla paper in the
+upper-left slot and Ink Vials in the upper-right; a copy appears in the
+lower-left result slot when the selected page is valid. Taking it consumes one
+paper and, by default, one ink. An available vial refills an empty ink meter
+when inserted or when copying uses its last ink, and returns a vanilla glass
+bottle to the lower-right slot. Removing a bottle also retries a blocked refill.
+Refilling waits if that slot is full or contains another item. The `AZ` control sorts
+visible pages by name; `ALL` shows pages held across every desk tab. Search and
+category filtering narrow the view without granting new pages, and cross-tab
+copy selection is checked by the server.
+Selecting a stored page on the desk surface shows its Legacy-proportioned
+portrait preview and name above the player inventory.
 
 ## Linking Book
 
@@ -60,6 +110,10 @@ according to the configured Return Link policy.
 
 Server owners can set `descriptive_books.return_link_mode` in Rivencraft's
 server config to `ON_CREATION` (default), `ALWAYS`, or `DISABLED`.
+Age creation, persistence, lifecycle commands, configuration, backups, and
+administrator recovery are documented in [docs/AGES.md](docs/AGES.md).
+Data-pack runtime profiles are documented in
+[docs/AGE_PROFILES.md](docs/AGE_PROFILES.md).
 
 ## Requirements
 
@@ -77,6 +131,9 @@ view. Without either integration, Rivencraft uses its built-in animated linking
 panel. Clients can set `book_preview.mode` in
 `rivencraft-client.toml` to `AUTO`, `IMMERSIVE_PORTALS`, `PONDER`, or `LEGACY`.
 Unavailable optional renderers safely fall back to `LEGACY`.
+The complete backend matrix, supported combinations, cleanup behavior, and
+known upstream limits are documented in
+[docs/PREVIEW_COMPATIBILITY.md](docs/PREVIEW_COMPATIBILITY.md).
 
 ## Build and run
 

docs/AGES.md

@@ -1,9 +1,35 @@
-# Age administration
+# Age creation and administration
+
+## Creation
+
+A page-free Descriptive Book creates an Age when the player assigns a name and
+presses **Create**. Rivencraft immediately assigns a UUID, derives a unique
+Minecraft-safe dimension identifier from the requested name, rolls a seed and
+traits, and persists that definition before asking Dynamic Dimensions to create
+the runtime world. Names that normalize to the same identifier receive stable
+suffixes such as `_2` and `_3`.
+
+The selected terrain profile, biome distribution, lighting, weather, celestial
+period, celestial angle, and phase are deterministic and become part of the
+saved definition. A five-by-five cobblestone platform with clear headroom is
+prepared at a safe arrival point. The completed book and every copy carrying
+the same UUID resolve to that definition.
+
+Creating an Age can take several ticks. The book cannot be reopened while its
+creation request is active. If creation is interrupted after the definition is
+saved, using the book again resumes from the same immutable definition instead
+of rolling a replacement.
+
+## Persistence
 
 Rivencraft owns each Age definition for the lifetime of a world. A definition
 contains the Age UUID, canonical name, seed, generation version, runtime
 dimension identifier, spawn, and deterministic traits. Definitions are stored
 in the Overworld saved data and are never rerolled during ordinary loading.
+Runtime terrain and entity data remain in the normal world dimension storage
+managed by Minecraft and Dynamic Dimensions. Back up the complete world folder
+while the server is stopped; copying only a dimension folder does not preserve
+the authoritative Age registry.
 
 ## Lifecycle
 
@@ -37,3 +63,47 @@ The commands require permission level 2.
 
 Opening a Descriptive Book for an unloaded Age loads it again from its saved
 definition.
+
+## Configuration
+
+Rivencraft writes gameplay settings to the world/server configuration managed
+by NeoForge. `descriptive_books.return_link_mode` accepts:
+
+- `ON_CREATION` (default): create one Return Link the first time a player
+  enters each Age.
+- `ALWAYS`: create a Return Link after every successful Descriptive Book trip.
+- `DISABLED`: never create Return Links automatically.
+
+Each client has a separate `rivencraft-client.toml`. Its `book_preview.mode`
+setting accepts `AUTO`, `IMMERSIVE_PORTALS`, `PONDER`, or `LEGACY`. This changes
+only presentation and cannot change server-side Age generation or travel
+validation. See [PREVIEW_COMPATIBILITY.md](PREVIEW_COMPATIBILITY.md) for the
+selection matrix and integration limits.
+
+Runtime generation profiles are server data-pack resources. Their schema,
+override rules, reload behavior, and deterministic fallback are documented in
+[AGE_PROFILES.md](AGE_PROFILES.md).
+
+## Administrator recovery
+
+Use this sequence when a book cannot load an existing Age:
+
+1. Stop the server and make a copy of the complete world folder.
+2. Start the server and run `/rivencraft age list`. Confirm that the expected
+   canonical name and dimension identifier remain registered.
+3. If the Age is listed as unloaded, open its Descriptive Book to reload it.
+   This keeps the UUID, seed, profile, traits, and existing world folder.
+4. If a data-pack profile is missing or invalid, restore or repair that pack,
+   run `/reload`, then unload and reopen the Age. A removed custom profile uses
+   the deterministic `rivencraft:standard` fallback and logs the substitution.
+5. If the definition is missing, restore the complete world backup. Moving a
+   dimension folder into another world cannot reconstruct its UUID or books.
+6. If the definition exists but its dimension data is damaged, restore the
+   matching dimension data and authoritative world saved data from the same
+   backup generation. Do not combine them from different backups.
+
+There is intentionally no delete command in Milestone 3. Do not manually
+delete an Age definition or rename its dimension folder: books may exist in
+inventories, containers, Book Stands, or unloaded chunks, and would be
+orphaned. `/rivencraft age unload` is the supported reversible maintenance
+operation.

docs/ASSET_PROVENANCE.md

@@ -0,0 +1,22 @@
+# Asset provenance
+
+Rivencraft reuses selected assets from
+[Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) under that
+project's GNU LGPL v3 license. Rivencraft itself uses the same license.
+
+| Rivencraft asset | Upstream asset | Upstream revision | Changes |
+| --- | --- | --- | --- |
+| `assets/rivencraft/textures/item/page.png` | `assets/mystcraft/textures/items/page_background.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/gui/notebook_pages.png` | `assets/mystcraft/gui/bookui_pagel.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; Notebook draws the native 30×40 page at atlas coordinates `(156, 0)` |
+| `assets/rivencraft/textures/item/writing_desk.png` | `assets/mystcraft/textures/items/writingdesk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/block/writing_desk.png` | `assets/mystcraft/textures/entity/desk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/block/writing_desk_wood.png` and `writing_desk_inlay.png` | `assets/mystcraft/textures/entity/desk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Cropped opaque wood and red inlay regions for the two-block model |
+| `assets/rivencraft/textures/gui/writing_desk_legacy.png` | `assets/mystcraft/gui/writingdesk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; full desk panel, tabs, and cycling controls at original atlas coordinates |
+| `assets/rivencraft/textures/gui/scrollbar.png` | `assets/mystcraft/gui/scrollbar.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; tiled track and normal/pressed thumb |
+| `assets/rivencraft/textures/item/linking_book_unwritten.png` | `assets/mystcraft/textures/items/unlinked.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/item/page_link_panel.png` | `page_background.png` and `PageBuilder.BasicPageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Reproduces the legacy 160 px scale, black panel at `(25,30)`–`(135,75)`, and 128 px resample |
+| `assets/rivencraft/textures/item/page_symbol*.png` and `page_unresolved.png` | `page_background.png`, `textures/symbolcomponents.png`, `WordData`, `ModSymbols`, and `PageBuilder.PageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Static 1.21.1 renditions of the legacy runtime-composed four-word symbol pages; `normal_time` uses the legacy Full Length poem |
+
+Mystcraft Legacy identifies XCompWiz as its project developer and includes the
+full LGPL v3 text in its root `LICENSE` file. Rivencraft's root `LICENSE`
+provides the same license terms.

docs/PORTING.md

@@ -31,9 +31,10 @@ acceptance issue and all required implementation issues are complete.
    **Complete.**
 3. **Ages** — persistent generated dimensions, deterministic traits,
    lifecycle management, data-pack integration, and optional destination
-   renderer compatibility. **Active.** See
+   renderer compatibility. **Complete.** See
    [Milestone 3](https://gitea.tail180fb1.ts.net/dnorberg/rivencraft/milestone/8).
 4. **Writing system** — pages, symbols, notebooks, desks, and book assembly.
+   **In progress.**
 5. **Age grammar** — translate symbol combinations into modern biome, noise,
    dimension-type, and world-generation configuration. Optional integrations
    may add composable biome regions and seasonal behavior.
@@ -53,15 +54,23 @@ documented in [AGE_PROFILES.md](AGE_PROFILES.md).
 The core mod must remain usable without Create, Ponder, or Immersive Portals.
 The built-in legacy animation is the dependency-free destination preview.
 Optional preview modes may use Create/Ponder snapshots or Immersive Portals
-live rendering when their dependencies are installed.
+live rendering when their dependencies are installed. The tested selection
+matrix and integration boundaries are documented in
+[PREVIEW_COMPATIBILITY.md](PREVIEW_COMPATIBILITY.md).
 
 The writing system and Age grammar will build on the existing page-free Age
 path. Page-free books remain a useful deterministic fallback and test fixture
 after written symbol combinations become available.
 
+Milestone 4 begins with a versioned, data-pack-defined symbol catalog and an
+immutable ordered-writing model. See [WRITING_DATA.md](WRITING_DATA.md). These
+contracts preserve unknown symbol identifiers and store author intent; they do
+not interpret symbols into Age generation, which remains Milestone 5 work.
+
 ## Provenance rules
 
 - New code uses the `net.dnorberg.rivencraft` package.
+- Reused legacy art is recorded in [ASSET_PROVENANCE.md](ASSET_PROVENANCE.md).
 - Adapted Mystcraft code retains its upstream copyright notice and is tracked
   in a nearby source comment or commit.
 - Generated, binary, and third-party dependency content is not copied from the

docs/PREVIEW_COMPATIBILITY.md

@@ -0,0 +1,78 @@
+# Destination preview compatibility
+
+Rivencraft has three destination preview backends. The selected backend is a
+client presentation detail; the server validates travel and Age generation is
+independent of every preview integration.
+
+## Selection matrix
+
+Set `book_preview.mode` in `rivencraft-client.toml`.
+
+| Configured mode | Immersive Portals installed | Create/Ponder installed | Selected backend |
+| --- | --- | --- | --- |
+| `AUTO` | yes | either | Immersive Portals |
+| `AUTO` | no | yes | Ponder snapshot |
+| `AUTO` | no | no | built-in legacy animation |
+| `IMMERSIVE_PORTALS` | yes | either | Immersive Portals |
+| `IMMERSIVE_PORTALS` | no | either | built-in legacy animation |
+| `PONDER` | either | yes | Ponder snapshot |
+| `PONDER` | either | no | built-in legacy animation |
+| `LEGACY` | either | either | built-in legacy animation |
+
+Explicit optional modes fall back directly to `LEGACY`. They do not silently
+select the other optional integration. GameTests exercise every row and every
+dependency-presence permutation.
+
+## Book behavior
+
+Held Linking and Descriptive Books render the selected backend in the preview
+panel. Immersive Portals additionally exposes **Explore**: the player remains
+at the opening position, mouse look controls the remote camera, and
+right-click returns to the standard book view.
+
+Books on a Book Stand use the same preview panel, but Explore is disabled so
+the player cannot move away and leave a remote preview session owned by the
+stand screen. Closing either screen releases its server chunk loader. Linking,
+disconnecting, unloading the destination Age, and stopping the server also
+release affected loaders.
+
+The Immersive Portals backend force-loads the initial 3 by 3 destination area
+before registering its wider preview chunk loader. The Ponder backend clears
+the previous snapshot before applying replacement block data. The live backend
+clears its framebuffer on each render and restores the Minecraft viewport
+afterward. These rules prevent stale snapshot frames and book UI elements from
+being captured in the preview.
+
+## Supported combinations and upstream limits
+
+The compatibility baseline is Minecraft 1.21.1, NeoForge 21.1.251, Create
+6.0.10, and Immersive Portals 6.0.7. Core Age generation and the `LEGACY`
+backend run without Create or Immersive Portals; the headless GameTest server
+uses that dependency-free path.
+
+Immersive Portals 6.0.7 is incompatible with Sodium 0.8.13 for Minecraft
+1.21.1: its Sodium compatibility mixin references the removed
+`OcclusionCuller.Visitor` class and crashes while entering a world. Sodium
+0.6.13 avoids that specific mixin failure. This compatibility boundary belongs
+to Immersive Portals and Sodium, before Rivencraft's preview code runs.
+
+Immersive Portals reports that some Create contraptions can be invisible when
+the two mods are installed together. Rivencraft does not replace either mod's
+world or contraption renderer, so this remains an upstream rendering limit.
+The `PONDER` or `LEGACY` mode is the supported fallback when live rendering is
+unstable in a particular graphics or mod configuration.
+
+## Release verification
+
+For preview-related releases:
+
+1. Run `./gradlew runGameTestServer` to verify the complete selection matrix,
+   core Age creation, persistence, and travel without optional renderers.
+2. Open held Linking and Descriptive Books once with each available backend.
+3. Open both book types from a Book Stand and confirm Explore is disabled.
+4. With Immersive Portals, enter and leave Explore, travel between dimensions,
+   close the screen, and disconnect; confirm destination chunks render and no
+   preview loader remains active.
+5. With Ponder, reopen different destinations and confirm the previous
+   snapshot does not bleed into the next one.
+

docs/WRITING_DATA.md

@@ -0,0 +1,93 @@
+# Writing and symbol data
+
+Milestone 4 stores what a player wrote without deciding what that writing does
+to an Age. Milestone 5 owns grammar validation, symbol interaction, instability,
+and translation into biome, noise, dimension-type, and other world-generation
+configuration.
+
+## Symbol catalog
+
+The authoritative server catalog loads JSON resources from
+`data/<namespace>/rivencraft/symbols/<path>.json`. The resource ID is the
+symbol ID. For example, `data/rivencraft/rivencraft/symbols/terrain/standard.json`
+defines `rivencraft:terrain/standard`.
+
+Schema version 1 contains display metadata only:
+
+```json
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.terrain.standard",
+  "description": "symbol.rivencraft.terrain.standard.description",
+  "category": "rivencraft:terrain"
+}
+```
+
+`name` and `description` are translation keys, not arbitrary formatted text or
+executable behavior. `category` is a namespaced organizational identifier.
+Invalid definitions are logged and excluded by the server. Menus and future
+page synchronization must obtain resolved display metadata from the server;
+clients never make a symbol valid by naming it.
+
+Rivencraft ships a small catalog covering terrain, biomes, lighting, weather,
+celestial behavior, and features. It exists to exercise the complete writing
+workflow before Milestone 5 implements the full legacy grammar.
+
+## Persistent writing
+
+`SymbolReference` stores only a namespaced symbol ID. `WritingEntry` is either
+a symbol reference or a baseline link-panel marker. `OrderedWriting` retains up
+to 256 entries in exact player-authored order. All three contracts have both
+persistent codecs and bounded network codecs.
+
+Removing a data pack never removes its IDs from saved writing. A missing ID is
+resolved as client-safe **Unresolved Symbol** display metadata while retaining
+the original namespaced ID for diagnostics and later restoration. This is
+deliberately different from treating an unknown symbol as valid grammar.
+
+## Pages
+
+The single stackable `rivencraft:page` item has a bounded, persistent
+`rivencraft:page_content` component. Its explicit states are blank, symbol,
+unresolved symbol, and baseline link panel. Symbol and unresolved-symbol pages
+retain their namespaced symbol reference; unresolved pages can be inspected and
+removed but are rejected as usable writing until their data pack returns.
+
+Only server-side writing operations may create a known symbol
+page or link panel from vanilla paper. The shared `PageItem` creation and validation gates reject
+new pages for identifiers absent from the server catalog. Later Writing Desk
+and Book Binder packets must call these gates rather than accepting page
+contents supplied by a client.
+
+The item model uses server-assigned custom-model data derived from the symbol
+identifier. Built-in pages reproduce Mystcraft Legacy's four-word poem
+composition from its page background and symbol-component sheet. Data-pack
+symbols without a bundled resource-pack model use the legacy question-mark
+fallback while keeping their real identifier and display metadata.
+
+The Notebook surface displays pages by their persistent slot index instead of
+packing occupied pages together. Empty positions through the last placed page
+appear darkened. While carrying a Page, all available positions are shown for
+placement. The surface draws the native 30×40 portrait page region from
+Legacy's book UI atlas; symbols are layered at a uniform scale, while the
+square item models remain unchanged in inventories.
+
+## Ink and baseline link panels
+
+An Ink Vial is crafted from two black dye, a glass bottle, and a water bucket.
+The bucket remains after crafting. Each vial holds 16 ink units, stored in a
+persistent, network-synchronized component; only vials with identical remaining
+ink stack together. When depleted, a vial returns a glass bottle that can be
+used to craft another. The animated item texture comes from Mystcraft Legacy.
+
+The server config sets ink costs independently for symbol copying (default one
+unit) and baseline link-panel preparation (default two units). To prepare a
+panel, hold vanilla paper in one hand and use an Ink Vial in the other. The
+server checks the held items and sufficient ink before consuming
+anything. A stack of paper yields exactly one Link Panel Page per use;
+if the inventory is full, the result is dropped instead of deleted. Symbol
+copying is implemented by the Writing Desk: it previews a copy of the selected
+resolved page, then spends paper and ink only when that copy is taken. The
+desk's 16-unit ink meter refills from an Ink Vial when needed and returns a
+vanilla glass bottle. Link-property modifiers are
+deferred beyond this baseline flow.

gradle.properties

@@ -35,7 +35,7 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. Rivencraft uses the x.y.z.b policy documented in README.md.
-mod_version=0.2.28.0
+mod_version=0.3.6.9
 immersive_portals_version=6.0.7
 # The group ID for the mod. It is only important when publishing as an artifact to a Maven repository.
 # This should match the base package used for the mod sources.

src/main/java/net/dnorberg/rivencraft/Rivencraft.java

@@ -4,6 +4,7 @@ import com.mojang.logging.LogUtils;
 import net.dnorberg.rivencraft.registry.ModCreativeTabs;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
 import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.registry.ModMenus;
 import net.dnorberg.rivencraft.registry.ModSounds;
 import net.dnorberg.rivencraft.registry.ModBlocks;
 import net.dnorberg.rivencraft.registry.ModBlockEntities;
@@ -18,6 +19,7 @@ import net.dnorberg.rivencraft.config.RivencraftClientConfig;
 import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.book.AgeWeatherService;
 import net.dnorberg.rivencraft.book.AgeRuntimeProfiles;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.fml.ModContainer;
 import net.neoforged.fml.common.Mod;
@@ -40,6 +42,7 @@ public final class Rivencraft {
         ModBlocks.register(modEventBus);
         ModBlockEntities.register(modEventBus);
         ModItems.register(modEventBus);
+        ModMenus.register(modEventBus);
         ModSounds.register(modEventBus);
         ModCreativeTabs.register(modEventBus);
         NeoForge.EVENT_BUS.addListener(BookStandConversionHandler::onRightClickBlock);
@@ -50,6 +53,7 @@ public final class Rivencraft {
         NeoForge.EVENT_BUS.addListener(AgeLifecycleEvents::onServerStopping);
         NeoForge.EVENT_BUS.addListener(RivencraftCommands::register);
         NeoForge.EVENT_BUS.addListener(AgeRuntimeProfiles::register);
+        NeoForge.EVENT_BUS.addListener(SymbolCatalog::register);
         LOGGER.info("Initializing Rivencraft");
     }
 }

src/main/java/net/dnorberg/rivencraft/block/WritingDeskBlock.java

@@ -0,0 +1,92 @@
+package net.dnorberg.rivencraft.block;
+
+import com.mojang.serialization.MapCodec;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Containers;
+import net.minecraft.world.InteractionResult;
+import net.minecraft.world.SimpleMenuProvider;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.context.BlockPlaceContext;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.BaseEntityBlock;
+import net.minecraft.world.level.block.RenderShape;
+import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.level.block.state.StateDefinition;
+import net.minecraft.world.level.block.state.properties.BlockStateProperties;
+import net.minecraft.world.level.block.state.properties.DirectionProperty;
+import net.minecraft.world.level.block.state.properties.BooleanProperty;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.entity.LivingEntity;
+import org.jetbrains.annotations.Nullable;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.phys.BlockHitResult;
+
+public final class WritingDeskBlock extends BaseEntityBlock {
+    public static final MapCodec<WritingDeskBlock> CODEC = simpleCodec(WritingDeskBlock::new);
+    public static final DirectionProperty FACING = BlockStateProperties.HORIZONTAL_FACING;
+    public static final BooleanProperty EXTENSION = BooleanProperty.create("extension");
+
+    public WritingDeskBlock(Properties properties) {
+        super(properties);
+        registerDefaultState(stateDefinition.any().setValue(FACING, Direction.NORTH).setValue(EXTENSION, false));
+    }
+
+    @Override public MapCodec<? extends BaseEntityBlock> codec() { return CODEC; }
+    @Override protected void createBlockStateDefinition(StateDefinition.Builder<net.minecraft.world.level.block.Block, BlockState> builder) {
+        builder.add(FACING, EXTENSION);
+    }
+    @Override public BlockState getStateForPlacement(BlockPlaceContext context) {
+        Direction facing = context.getHorizontalDirection().getOpposite();
+        BlockPos extension = context.getClickedPos().relative(facing.getClockWise());
+        return context.getLevel().getBlockState(extension).canBeReplaced(context)
+                ? defaultBlockState().setValue(FACING, facing) : null;
+    }
+    @Override public void setPlacedBy(Level level, BlockPos pos, BlockState state,
+                                      @Nullable LivingEntity placer, ItemStack stack) {
+        super.setPlacedBy(level, pos, state, placer, stack);
+        level.setBlock(pos.relative(state.getValue(FACING).getClockWise()),
+                state.setValue(EXTENSION, true), 3);
+    }
+    @Override protected RenderShape getRenderShape(BlockState state) { return RenderShape.MODEL; }
+    @Override public BlockEntity newBlockEntity(BlockPos pos, BlockState state) {
+        return state.getValue(EXTENSION) ? null : new WritingDeskBlockEntity(pos, state);
+    }
+    @Override protected InteractionResult useWithoutItem(BlockState state, Level level, BlockPos pos,
+                                                          Player player, BlockHitResult hit) {
+        BlockPos controller = state.getValue(EXTENSION)
+                ? pos.relative(state.getValue(FACING).getCounterClockWise()) : pos;
+        if (!level.isClientSide && player instanceof ServerPlayer serverPlayer
+                && level.getBlockEntity(controller) instanceof WritingDeskBlockEntity desk) {
+            serverPlayer.openMenu(new SimpleMenuProvider(
+                    (id, inventory, ignored) -> new WritingDeskMenu(id, inventory, desk),
+                    Component.translatable("container.rivencraft.writing_desk")),
+                    buffer -> {
+                        buffer.writeBlockPos(controller);
+                        WritingDeskCatalog.write(buffer, WritingDeskCatalog.available(desk));
+                    });
+        }
+        return InteractionResult.sidedSuccess(level.isClientSide);
+    }
+    @Override protected void onRemove(BlockState state, Level level, BlockPos pos, BlockState replacement, boolean moving) {
+        if (!state.is(replacement.getBlock())) {
+            if (!level.isClientSide && !state.getValue(EXTENSION)
+                    && level.getBlockEntity(pos) instanceof WritingDeskBlockEntity desk) {
+                Containers.dropContents(level, pos, desk);
+                level.updateNeighbourForOutputSignal(pos, this);
+            }
+            BlockPos other = pos.relative(state.getValue(FACING).getClockWise(),
+                    state.getValue(EXTENSION) ? -1 : 1);
+            BlockState otherState = level.getBlockState(other);
+            if (otherState.is(this) && otherState.getValue(EXTENSION) != state.getValue(EXTENSION)) {
+                level.setBlock(other, net.minecraft.world.level.block.Blocks.AIR.defaultBlockState(), 35);
+            }
+        }
+        super.onRemove(state, level, pos, replacement, moving);
+    }
+}

src/main/java/net/dnorberg/rivencraft/block/entity/WritingDeskBlockEntity.java

@@ -0,0 +1,196 @@
+package net.dnorberg.rivencraft.block.entity;
+
+import net.dnorberg.rivencraft.item.InkVialItem;
+import net.dnorberg.rivencraft.writing.WritingInkService;
+import net.dnorberg.rivencraft.registry.ModBlockEntities;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.core.NonNullList;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ClientGamePacketListener;
+import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+
+/** Collection tabs, paper, ink vials and empty-vial return are owned by the block. */
+public final class WritingDeskBlockEntity extends BlockEntity implements Container {
+    public static final int COLLECTIONS = 88;
+    public static final int INK = COLLECTIONS;
+    public static final int RETURN = INK + 1;
+    public static final int PAPER = INK + 2;
+    /** Unused by new desks; retained so old saves cannot silently lose slot contents. */
+    public static final int LEGACY_OUTPUT = INK + 3;
+    public static final int SIZE = INK + 4;
+    private NonNullList<ItemStack> items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
+    private int activeCollection;
+    private int inkRemaining;
+    private ItemStack displayPage = ItemStack.EMPTY;
+
+    public WritingDeskBlockEntity(BlockPos pos, BlockState state) {
+        super(ModBlockEntities.WRITING_DESK.get(), pos, state);
+    }
+
+    public int activeCollection() { return activeCollection; }
+    public int inkRemaining() { return inkRemaining; }
+    public ItemStack displayPage() { return displayPage; }
+    public void setDisplayPage(ItemStack page) {
+        ItemStack next = page.isEmpty() ? ItemStack.EMPTY : page.copyWithCount(1);
+        if (!ItemStack.matches(displayPage, next)) {
+            displayPage = next;
+            setChanged();
+        }
+    }
+    public void setActiveCollection(int index) {
+        if (index >= 0 && index < COLLECTIONS && activeCollection != index) {
+            activeCollection = index;
+            setChanged();
+        }
+    }
+
+    @Override public int getContainerSize() { return SIZE; }
+    @Override public boolean isEmpty() { return items.stream().allMatch(ItemStack::isEmpty); }
+    @Override public ItemStack getItem(int slot) { return items.get(slot); }
+    @Override public ItemStack removeItem(int slot, int amount) {
+        ItemStack removed = ContainerHelper.removeItem(items, slot, amount);
+        if (!removed.isEmpty()) {
+            if (slot < COLLECTIONS) displayPage = ItemStack.EMPTY;
+            setChanged();
+            if (slot == RETURN) refillEmptyInkBar();
+        }
+        return removed;
+    }
+    @Override public ItemStack removeItemNoUpdate(int slot) { return ContainerHelper.takeItem(items, slot); }
+    @Override public void setItem(int slot, ItemStack stack) {
+        items.set(slot, stack);
+        if (stack.getCount() > getMaxStackSize()) stack.setCount(getMaxStackSize());
+        if (slot < COLLECTIONS) displayPage = ItemStack.EMPTY;
+        setChanged();
+        if (slot == INK || slot == RETURN) refillEmptyInkBar();
+    }
+    @Override public boolean stillValid(Player player) {
+        return level != null && level.isLoaded(worldPosition)
+                && level.getBlockEntity(worldPosition) == this
+                && player.distanceToSqr(worldPosition.getX() + 0.5, worldPosition.getY() + 0.5,
+                        worldPosition.getZ() + 0.5) <= 64.0;
+    }
+    @Override public boolean canPlaceItem(int slot, ItemStack stack) {
+        if (slot < COLLECTIONS) return stack.is(ModItems.NOTEBOOK.get()) || stack.is(ModItems.PAGE.get());
+        return switch (slot) {
+            case INK -> stack.is(ModItems.INK_VIAL.get());
+            case RETURN -> false;
+            case PAPER -> stack.is(Items.PAPER);
+            case LEGACY_OUTPUT -> false;
+            default -> false;
+        };
+    }
+
+    private boolean hasBottleSpace() {
+        ItemStack returned = items.get(RETURN);
+        return returned.isEmpty() || returned.is(Items.GLASS_BOTTLE)
+                && returned.getCount() < returned.getMaxStackSize();
+    }
+
+    /** Consume one vial only when the empty meter can return its glass bottle. */
+    private void refillEmptyInkBar() {
+        if (level == null || level.isClientSide || inkRemaining != 0 || !hasBottleSpace()) return;
+        ItemStack vial = items.get(INK);
+        if (!vial.is(ModItems.INK_VIAL.get())) return;
+        int ink = Math.clamp(InkVialItem.remaining(vial), 0, InkVialItem.CAPACITY);
+        if (ink == 0) return;
+        inkRemaining = ink;
+        vial.shrink(1);
+        if (vial.isEmpty()) items.set(INK, ItemStack.EMPTY);
+        ItemStack returned = items.get(RETURN);
+        if (returned.isEmpty()) items.set(RETURN, new ItemStack(Items.GLASS_BOTTLE));
+        else returned.grow(1);
+        setChanged();
+    }
+
+    /** The output is virtual; inputs are committed only after a result can be given to a player. */
+    public boolean canConsumeCopyMaterials() {
+        ItemStack paper = items.get(PAPER);
+        if (!canPlaceItem(PAPER, paper) || paper.isEmpty()) return false;
+        int cost = WritingInkService.symbolCopyCost();
+        if (inkRemaining >= cost) return true;
+        ItemStack vial = items.get(INK);
+        return vial.is(ModItems.INK_VIAL.get()) && inkRemaining + InkVialItem.remaining(vial) >= cost
+                && hasBottleSpace();
+    }
+
+    public boolean consumeCopyMaterials() {
+        if (!canConsumeCopyMaterials()) return false;
+        int cost = WritingInkService.symbolCopyCost();
+        if (inkRemaining < cost) {
+            ItemStack vial = items.get(INK);
+            inkRemaining += Math.clamp(InkVialItem.remaining(vial), 0, InkVialItem.CAPACITY);
+            vial.shrink(1);
+            if (vial.isEmpty()) items.set(INK, ItemStack.EMPTY);
+            ItemStack returned = items.get(RETURN);
+            if (returned.isEmpty()) items.set(RETURN, new ItemStack(Items.GLASS_BOTTLE));
+            else returned.grow(1);
+        }
+        inkRemaining -= cost;
+        removeItem(PAPER, 1);
+        setChanged();
+        if (inkRemaining == 0) refillEmptyInkBar();
+        return true;
+    }
+    @Override public void setLevel(Level level) {
+        super.setLevel(level);
+        refillEmptyInkBar();
+    }
+    @Override public void clearContent() {
+        items.clear();
+        items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
+        inkRemaining = 0;
+        displayPage = ItemStack.EMPTY;
+        setChanged();
+    }
+    @Override protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+        super.loadAdditional(tag, registries);
+        items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
+        ContainerHelper.loadAllItems(tag, items, registries);
+        // Pre-88-tab desks stored materials in slots 4..7. Move them once;
+        // never interpret those stacks as newly added collection tabs.
+        if (tag.getInt("InventoryVersion") < 1) {
+            for (int i = 0; i < 4; i++) {
+                items.set(INK + i, items.get(4 + i));
+                items.set(4 + i, ItemStack.EMPTY);
+            }
+        }
+        activeCollection = Math.clamp(tag.getInt("ActiveCollection"), 0, COLLECTIONS - 1);
+        inkRemaining = Math.clamp(tag.getInt("InkRemaining"), 0, InkVialItem.CAPACITY);
+        displayPage = tag.contains("DisplayPage", CompoundTag.TAG_COMPOUND)
+                ? ItemStack.parse(registries, tag.getCompound("DisplayPage")).orElse(ItemStack.EMPTY)
+                : ItemStack.EMPTY;
+        refillEmptyInkBar();
+    }
+    @Override protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
+        super.saveAdditional(tag, registries);
+        ContainerHelper.saveAllItems(tag, items, registries);
+        tag.putInt("InventoryVersion", 1);
+        tag.putInt("ActiveCollection", activeCollection);
+        tag.putInt("InkRemaining", inkRemaining);
+        if (!displayPage.isEmpty()) tag.put("DisplayPage", displayPage.save(registries));
+    }
+    @Override public Packet<ClientGamePacketListener> getUpdatePacket() {
+        return ClientboundBlockEntityDataPacket.create(this);
+    }
+    @Override public CompoundTag getUpdateTag(HolderLookup.Provider registries) {
+        return saveWithoutMetadata(registries);
+    }
+    @Override public void setChanged() {
+        super.setChanged();
+        if (level != null && !level.isClientSide) {
+            level.sendBlockUpdated(worldPosition, getBlockState(), getBlockState(), 2);
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/book/AgePersistenceGameTests.java

@@ -0,0 +1,132 @@
+package net.dnorberg.rivencraft.book;
+
+import java.util.UUID;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.BlockPos;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.ListTag;
+import net.minecraft.resources.ResourceLocation;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+/** Saved-data migration and round-trip acceptance coverage for persistent Ages. */
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class AgePersistenceGameTests {
+    private AgePersistenceGameTests() {
+    }
+
+    @GameTest(template = "empty")
+    public static void everyTraitCombinationRoundTripsWithoutRerolling(GameTestHelper helper) {
+        ListTag entries = new ListTag();
+        AgeTraits.BiomeDistribution[] distributions = AgeTraits.BiomeDistribution.values();
+        AgeTraits.Lighting[] lightingValues = AgeTraits.Lighting.values();
+        AgeTraits.Weather[] weatherValues = AgeTraits.Weather.values();
+
+        for (int index = 0; index < distributions.length; index++) {
+            UUID id = new UUID(0x524956454E000000L + index, 0x4147450000000000L + index);
+            AgeTraits traits = new AgeTraits(
+                    distributions[index],
+                    lightingValues[index % lightingValues.length],
+                    weatherValues[index % weatherValues.length],
+                    index == 0 ? AgeTraits.STOPPED_CELESTIAL_PERIOD : 0.25D + index * 0.15D,
+                    index * 37.5F,
+                    index * 0.1F
+            );
+            entries.add(entry(
+                    id,
+                    "Persistent " + distributions[index],
+                    9000L + index,
+                    AgeGenerationProfiles.all().get(index % AgeGenerationProfiles.all().size()),
+                    3 + index,
+                    1200L + index,
+                    ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "age/persistent_" + index),
+                    new BlockPos(index, 70 + index, -index),
+                    traits
+            ));
+        }
+
+        CompoundTag root = new CompoundTag();
+        root.put("Ages", entries);
+        AgeRegistrySavedData first = AgeRegistrySavedData.load(root, helper.getLevel().registryAccess());
+        CompoundTag serialized = first.save(new CompoundTag(), helper.getLevel().registryAccess());
+        AgeRegistrySavedData restored = AgeRegistrySavedData.load(serialized, helper.getLevel().registryAccess());
+
+        for (int index = 0; index < distributions.length; index++) {
+            UUID id = new UUID(0x524956454E000000L + index, 0x4147450000000000L + index);
+            helper.assertValueEqual(restored.find(id).orElseThrow(), first.find(id).orElseThrow(),
+                    distributions[index] + " and its weather, lighting, celestial, and identity data must round-trip");
+        }
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void legacyDefinitionReceivesStableDefaults(GameTestHelper helper) {
+        UUID id = UUID.fromString("4d797374-6372-6166-7400-000000000001");
+        CompoundTag legacy = new CompoundTag();
+        legacy.putUUID("Id", id);
+        legacy.putString("Name", "  Legacy Age  ");
+        legacy.putLong("Seed", 8675309L);
+        legacy.putString("GenerationProfile", AgeDefinition.RANDOM_VANILLA_PROFILE.toString());
+        legacy.putLong("CreatedGameTime", 42L);
+        ListTag entries = new ListTag();
+        entries.add(legacy);
+        CompoundTag root = new CompoundTag();
+        root.put("Ages", entries);
+
+        AgeRegistrySavedData migrated = AgeRegistrySavedData.load(root, helper.getLevel().registryAccess());
+        AgeDefinition definition = migrated.find(id).orElseThrow();
+        helper.assertValueEqual(definition.id(), id, "Migration must retain the Age UUID");
+        helper.assertValueEqual(definition.name(), "Legacy Age", "Migration must normalize and retain the Age name");
+        helper.assertValueEqual(definition.seed(), 8675309L, "Migration must retain the Age seed");
+        helper.assertValueEqual(definition.generationProfile(), AgeDefinition.RANDOM_VANILLA_PROFILE,
+                "Migration must retain the legacy generation profile for deterministic runtime fallback");
+        helper.assertValueEqual(definition.generationVersion(), 1,
+                "Definitions predating generation versions must receive version 1");
+        helper.assertValueEqual(definition.dimensionId(), AgeDefinition.dimensionId(id),
+                "Definitions predating named dimensions must retain the UUID-derived dimension");
+        helper.assertValueEqual(definition.traits(), AgeTraits.LEGACY_DEFAULTS,
+                "Definitions predating traits must receive stable legacy defaults");
+
+        CompoundTag serialized = migrated.save(new CompoundTag(), helper.getLevel().registryAccess());
+        AgeDefinition reloaded = AgeRegistrySavedData.load(serialized, helper.getLevel().registryAccess())
+                .find(id).orElseThrow();
+        helper.assertValueEqual(reloaded, definition, "A migrated definition must not reroll on its next restart");
+        helper.succeed();
+    }
+
+    private static CompoundTag entry(
+            UUID id,
+            String name,
+            long seed,
+            ResourceLocation profile,
+            int version,
+            long createdTime,
+            ResourceLocation dimension,
+            BlockPos spawn,
+            AgeTraits traits
+    ) {
+        CompoundTag entry = new CompoundTag();
+        entry.putUUID("Id", id);
+        entry.putString("Name", name);
+        entry.putLong("Seed", seed);
+        entry.putString("GenerationProfile", profile.toString());
+        entry.putInt("GenerationVersion", version);
+        entry.putLong("CreatedGameTime", createdTime);
+        entry.putString("Dimension", dimension.toString());
+        entry.putInt("SpawnX", spawn.getX());
+        entry.putInt("SpawnY", spawn.getY());
+        entry.putInt("SpawnZ", spawn.getZ());
+        CompoundTag serializedTraits = new CompoundTag();
+        serializedTraits.putString("BiomeDistribution", traits.biomeDistribution().name());
+        serializedTraits.putString("Lighting", traits.lighting().name());
+        serializedTraits.putString("Weather", traits.weather().name());
+        serializedTraits.putDouble("CelestialPeriod", traits.celestialPeriod());
+        serializedTraits.putFloat("CelestialAngle", traits.celestialAngle());
+        serializedTraits.putFloat("CelestialPhase", traits.celestialPhase());
+        entry.put("Traits", serializedTraits);
+        return entry;
+    }
+}

src/main/java/net/dnorberg/rivencraft/book/AgeRegistrySavedData.java

@@ -103,7 +103,7 @@ public final class AgeRegistrySavedData extends SavedData {
         return created;
     }
 
-    private static AgeRegistrySavedData load(CompoundTag tag, HolderLookup.Provider registries) {
+    static AgeRegistrySavedData load(CompoundTag tag, HolderLookup.Provider registries) {
         AgeRegistrySavedData data = new AgeRegistrySavedData();
         ListTag serializedAges = tag.getList(AGES_TAG, CompoundTag.TAG_COMPOUND);
         for (int index = 0; index < serializedAges.size(); index++) {
@@ -111,12 +111,18 @@ public final class AgeRegistrySavedData extends SavedData {
             if (!entry.hasUUID(ID_TAG)) {
                 continue;
             }
-            ResourceLocation profile = ResourceLocation.tryParse(entry.getString(PROFILE_TAG));
+            ResourceLocation profile = entry.contains(PROFILE_TAG, CompoundTag.TAG_STRING)
+                    && !entry.getString(PROFILE_TAG).isBlank()
+                    ? ResourceLocation.tryParse(entry.getString(PROFILE_TAG))
+                    : null;
             if (profile == null) {
                 profile = AgeDefinition.RANDOM_VANILLA_PROFILE;
             }
             UUID id = entry.getUUID(ID_TAG);
-            ResourceLocation dimensionId = ResourceLocation.tryParse(entry.getString(DIMENSION_TAG));
+            ResourceLocation dimensionId = entry.contains(DIMENSION_TAG, CompoundTag.TAG_STRING)
+                    && !entry.getString(DIMENSION_TAG).isBlank()
+                    ? ResourceLocation.tryParse(entry.getString(DIMENSION_TAG))
+                    : null;
             if (dimensionId == null) {
                 dimensionId = AgeDefinition.dimensionId(id);
             }

src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java

@@ -2,12 +2,20 @@ package net.dnorberg.rivencraft.client;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.registry.ModBlockEntities;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.client.renderer.item.ItemProperties;
+import net.minecraft.resources.ResourceLocation;
 import net.neoforged.api.distmarker.Dist;
 import net.neoforged.bus.api.SubscribeEvent;
 import net.neoforged.fml.common.EventBusSubscriber;
 import net.neoforged.fml.event.lifecycle.FMLClientSetupEvent;
 import net.neoforged.neoforge.common.NeoForge;
 import net.neoforged.neoforge.client.event.EntityRenderersEvent;
+import net.neoforged.neoforge.client.event.RegisterMenuScreensEvent;
+import net.dnorberg.rivencraft.client.screen.NotebookScreen;
+import net.dnorberg.rivencraft.client.screen.WritingDeskScreen;
+import net.dnorberg.rivencraft.registry.ModMenus;
 
 @EventBusSubscriber(modid = Rivencraft.MOD_ID, value = Dist.CLIENT)
 public final class ClientEvents {
@@ -17,10 +25,22 @@ public final class ClientEvents {
     @SubscribeEvent
     public static void registerRenderers(EntityRenderersEvent.RegisterRenderers event) {
         event.registerBlockEntityRenderer(ModBlockEntities.BOOK_STAND.get(), BookStandRenderer::new);
+        event.registerBlockEntityRenderer(ModBlockEntities.WRITING_DESK.get(), WritingDeskRenderer::new);
+    }
+
+    @SubscribeEvent
+    public static void registerScreens(RegisterMenuScreensEvent event) {
+        event.register(ModMenus.NOTEBOOK.get(), NotebookScreen::new);
+        event.register(ModMenus.WRITING_DESK.get(), WritingDeskScreen::new);
     }
 
     @SubscribeEvent
     public static void clientSetup(FMLClientSetupEvent event) {
+        event.enqueueWork(() -> ItemProperties.register(
+                ModItems.LINKING_BOOK.get(),
+                ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "bound"),
+                (stack, level, entity, seed) -> stack.has(ModDataComponents.LINK_TARGET.get()) ? 1.0F : 0.0F
+        ));
         NeoForge.EVENT_BUS.addListener(ClientBookInteractionHandler::onRightClickItem);
         NeoForge.EVENT_BUS.addListener(ClientBookInteractionHandler::onRightClickBlock);
         NeoForge.EVENT_BUS.addListener(ClientBookExploreOverlay::onClientTickPre);

src/main/java/net/dnorberg/rivencraft/client/ClientWritingDeskCatalog.java

@@ -0,0 +1,20 @@
+package net.dnorberg.rivencraft.client;
+
+import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.dnorberg.rivencraft.network.WritingDeskCatalogPayload;
+import net.minecraft.client.Minecraft;
+import net.neoforged.neoforge.network.handling.IPayloadContext;
+
+public final class ClientWritingDeskCatalog {
+    private ClientWritingDeskCatalog() {}
+
+    public static void handle(WritingDeskCatalogPayload payload, IPayloadContext context) {
+        context.enqueueWork(() -> {
+            var player = Minecraft.getInstance().player;
+            if (player != null && player.containerMenu instanceof WritingDeskMenu menu
+                    && menu.containerId == payload.containerId()) {
+                menu.setCatalog(payload.symbols());
+            }
+        });
+    }
+}

src/main/java/net/dnorberg/rivencraft/client/WritingDeskRenderer.java

@@ -0,0 +1,55 @@
+package net.dnorberg.rivencraft.client;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.math.Axis;
+import net.dnorberg.rivencraft.block.WritingDeskBlock;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.blockentity.BlockEntityRenderer;
+import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
+import net.minecraft.world.item.ItemDisplayContext;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+/** Visible selected page and loaded paper, as on the Legacy desk. */
+public final class WritingDeskRenderer implements BlockEntityRenderer<WritingDeskBlockEntity> {
+    public WritingDeskRenderer(BlockEntityRendererProvider.Context context) {}
+
+    @Override public void render(WritingDeskBlockEntity desk, float partialTick, PoseStack pose,
+                                 MultiBufferSource buffers, int light, int overlay) {
+        int paper = desk.getItem(WritingDeskBlockEntity.PAPER).getCount();
+        ItemStack page = desk.displayPage();
+        if (paper == 0 && page.isEmpty()) return;
+        pose.pushPose();
+        pose.translate(0.5, 0, 0.5);
+        pose.mulPose(Axis.YP.rotationDegrees(
+                180.0F - desk.getBlockState().getValue(WritingDeskBlock.FACING).toYRot()));
+        if (paper > 0) {
+            ItemStack sheet = new ItemStack(Items.PAPER);
+            int layers = Math.min(4, 1 + paper / 16);
+            for (int i = 0; i < layers; i++) {
+                drawFlat(desk, sheet, pose, buffers, light, overlay, 1.22, 0.27 + i * 0.008, -0.14, 0.55F);
+            }
+        }
+        if (!page.isEmpty()) {
+            drawFlat(desk, page, pose, buffers, light, overlay, 1.0, 0.572, 0.0, 0.8F);
+        }
+        pose.popPose();
+    }
+
+    private static void drawFlat(WritingDeskBlockEntity desk, ItemStack stack, PoseStack pose,
+                                 MultiBufferSource buffers, int light, int overlay,
+                                 double x, double y, double z, float scale) {
+        pose.pushPose();
+        pose.translate(x, y, z);
+        pose.mulPose(Axis.XP.rotationDegrees(90));
+        pose.scale(scale, scale, scale);
+        Minecraft.getInstance().getItemRenderer().renderStatic(stack, ItemDisplayContext.FIXED,
+                light, overlay, pose, buffers, desk.getLevel(), 0);
+        pose.popPose();
+    }
+
+    @Override public boolean shouldRenderOffScreen(WritingDeskBlockEntity blockEntity) { return true; }
+    @Override public int getViewDistance() { return 64; }
+}

src/main/java/net/dnorberg/rivencraft/client/preview/DestinationPreviewRenderers.java

@@ -1,44 +1,22 @@
 package net.dnorberg.rivencraft.client.preview;
 
 import net.dnorberg.rivencraft.config.RivencraftClientConfig;
+import net.dnorberg.rivencraft.compat.PreviewBackendSelector;
 import net.neoforged.fml.ModList;
 
 /** Selects the configured destination preview while keeping optional integrations optional. */
 public final class DestinationPreviewRenderers {
-    private enum Backend {
-        IMMERSIVE_PORTALS,
-        PONDER,
-        LEGACY
-    }
-
     private DestinationPreviewRenderers() {
     }
 
     public static DestinationPreviewRenderer create() {
         boolean ponderAvailable = ModList.get().isLoaded("create");
-        // The mode and priority are established before the optional IP renderer
-        // lands, so selecting it currently follows the documented safe fallback.
         boolean immersivePortalsAvailable = ModList.get().isLoaded("immersive_portals_core");
-        return switch (selectBackend(
+        return switch (PreviewBackendSelector.select(
                 RivencraftClientConfig.previewMode(), immersivePortalsAvailable, ponderAvailable)) {
             case IMMERSIVE_PORTALS -> new ImmersivePortalsDestinationPreviewRenderer();
             case PONDER -> new PonderDestinationPreviewRenderer();
             case LEGACY -> new LegacyDestinationPreviewRenderer();
         };
     }
-
-    private static Backend selectBackend(
-            RivencraftClientConfig.PreviewMode mode,
-            boolean immersivePortalsAvailable,
-            boolean ponderAvailable
-    ) {
-        return switch (mode) {
-            case AUTO -> immersivePortalsAvailable
-                    ? Backend.IMMERSIVE_PORTALS
-                    : ponderAvailable ? Backend.PONDER : Backend.LEGACY;
-            case IMMERSIVE_PORTALS -> immersivePortalsAvailable ? Backend.IMMERSIVE_PORTALS : Backend.LEGACY;
-            case PONDER -> ponderAvailable ? Backend.PONDER : Backend.LEGACY;
-            case LEGACY -> Backend.LEGACY;
-        };
-    }
 }

src/main/java/net/dnorberg/rivencraft/client/preview/ImmersivePortalsDestinationPreviewRenderer.java

@@ -42,7 +42,11 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
 
     @Override
     public void accept(LinkPreviewPayload payload) {
+        if (destination != null) {
+            ImmersivePortalsPreviewAudioGuard.clear(destination.dimension());
+        }
         destination = payload;
+        ImmersivePortalsPreviewAudioGuard.mute(payload.dimension());
         resetView();
     }
 
@@ -118,6 +122,7 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
         FRAMEBUFFER.clear(true);
         minecraft.getMainRenderTarget().bindWrite(true);
         MyRenderHelper.restoreViewPort();
+        ImmersivePortalsPreviewAudioGuard.markCameraRestorePending();
         GuiPortalRendering.submitNextFrameRendering(info, FRAMEBUFFER);
         hasCompletedFrame = true;
         graphics.renderOutline(left, top, width, height, exploring ? 0xFFE0C36A : 0xFF7B6AA8);
@@ -234,5 +239,8 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
     public void close() {
         clearMovement();
         hasCompletedFrame = false;
+        if (destination != null) {
+            ImmersivePortalsPreviewAudioGuard.clear(destination.dimension());
+        }
     }
 }

src/main/java/net/dnorberg/rivencraft/client/preview/ImmersivePortalsPreviewAudioGuard.java

@@ -0,0 +1,62 @@
+package net.dnorberg.rivencraft.client.preview;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.Camera;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.world.level.Level;
+
+/** Prevents an Immersive Portals preview world from contributing sounds to a book screen. */
+public final class ImmersivePortalsPreviewAudioGuard {
+    private static ResourceKey<Level> mutedDimension;
+    private static boolean cameraRestorePending;
+
+    private ImmersivePortalsPreviewAudioGuard() {
+    }
+
+    public static void mute(ResourceKey<Level> dimension) {
+        mutedDimension = dimension;
+    }
+
+    public static void clear(ResourceKey<Level> dimension) {
+        if (dimension.equals(mutedDimension)) {
+            mutedDimension = null;
+        }
+    }
+
+    public static boolean shouldMute(ClientLevel level) {
+        Minecraft minecraft = Minecraft.getInstance();
+        return mutedDimension != null
+                && level.dimension().equals(mutedDimension)
+                && (minecraft.player == null || level != minecraft.player.level());
+    }
+
+    public static void markCameraRestorePending() {
+        cameraRestorePending = true;
+    }
+
+    /**
+     * Immersive Portals' GUI renderer leaves the shared main camera in the
+     * remote world after its end-of-frame render. Restore it before the next
+     * frame uses that camera for rain effects and the sound listener.
+     */
+    public static void restorePlayerCamera() {
+        Minecraft minecraft = Minecraft.getInstance();
+        if (!cameraRestorePending) {
+            return;
+        }
+        cameraRestorePending = false;
+        if (minecraft.level == null || minecraft.getCameraEntity() == null) {
+            return;
+        }
+
+        Camera camera = minecraft.gameRenderer.getMainCamera();
+        camera.setup(
+                minecraft.level,
+                minecraft.getCameraEntity(),
+                !minecraft.options.getCameraType().isFirstPerson(),
+                minecraft.options.getCameraType().isMirrored(),
+                camera.getPartialTickTime()
+        );
+    }
+}

src/main/java/net/dnorberg/rivencraft/client/screen/NotebookScreen.java

@@ -0,0 +1,324 @@
+package net.dnorberg.rivencraft.client.screen;
+
+import java.util.Locale;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.menu.NotebookMenu;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.client.gui.GuiGraphics;
+import net.minecraft.client.gui.components.Button;
+import net.minecraft.client.gui.components.EditBox;
+import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen;
+import net.minecraft.network.chat.Component;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.item.ItemStack;
+
+/** A page surface modelled on Legacy's folder GUI, backed by the Notebook menu. */
+public final class NotebookScreen extends AbstractContainerScreen<NotebookMenu> {
+    private static final int SURFACE_TOP = 20;
+    private static final int SURFACE_BOTTOM = 132;
+    private static final int SURFACE_RIGHT = 156;
+    private static final int PAGE_WIDTH = 30;
+    private static final int PAGE_HEIGHT = 40;
+    private static final int PAGE_STEP_X = 31;
+    private static final int PAGE_STEP_Y = 41;
+    private static final int PAGE_COLUMNS = 5;
+    private static final ResourceLocation PAGE_ATLAS = texture("gui/notebook_pages");
+    private static final ResourceLocation GENERIC_SYMBOL = texture("item/page_symbol");
+    private static final ResourceLocation UNRESOLVED_SYMBOL = texture("item/page_unresolved");
+    private static final ResourceLocation STANDARD_TERRAIN = texture("item/page_symbol_terrain_standard");
+    private static final ResourceLocation NATIVE_BIOMES = texture("item/page_symbol_biome_native");
+    private static final ResourceLocation NORMAL_LIGHTING = texture("item/page_symbol_lighting_normal");
+    private static final ResourceLocation NORMAL_WEATHER = texture("item/page_symbol_weather_normal");
+    private static final ResourceLocation NORMAL_TIME = texture("item/page_symbol_celestial_normal_time");
+    private static final ResourceLocation CAVES = texture("item/page_symbol_feature_caves");
+    private EditBox textInput;
+    private boolean draggingScrollbar;
+    private boolean surfaceClickPendingRelease;
+    private int selectedSlot = -1;
+    private int scroll;
+
+    public NotebookScreen(NotebookMenu menu, Inventory inventory, Component title) {
+        super(menu, inventory, title);
+        imageWidth = 176;
+        imageHeight = 213;
+        inventoryLabelY = 123;
+    }
+
+    @Override
+    protected void init() {
+        super.init();
+        Button sortButton = Button.builder(Component.literal("AZ"), button -> {})
+                .bounds(leftPos, topPos, 18, 18).build();
+        Button allButton = Button.builder(Component.literal("ALL"), button -> {})
+                .bounds(leftPos + 20, topPos, 26, 18).build();
+        sortButton.active = false;
+        allButton.active = false;
+        addRenderableWidget(sortButton);
+        addRenderableWidget(allButton);
+        textInput = new EditBox(font, leftPos + 48, topPos, 128, 18,
+                Component.translatable("screen.rivencraft.notebook.search"));
+        textInput.setMaxLength(32);
+        textInput.setHint(Component.translatable("screen.rivencraft.notebook.search"));
+        textInput.setResponder(value -> scroll = 0);
+        addRenderableWidget(textInput);
+    }
+
+    @Override
+    public void render(GuiGraphics graphics, int mouseX, int mouseY, float partialTick) {
+        super.render(graphics, mouseX, mouseY, partialTick);
+        int pageSlots = displayedPageSlots();
+        scroll = Math.min(scroll, maxScroll(pageSlots));
+        graphics.enableScissor(leftPos, topPos + SURFACE_TOP, leftPos + SURFACE_RIGHT,
+                topPos + SURFACE_BOTTOM);
+        for (int index = 0; index < pageSlots; index++) {
+            int x = leftPos + (index % PAGE_COLUMNS) * PAGE_STEP_X;
+            int y = topPos + SURFACE_TOP + (index / PAGE_COLUMNS) * PAGE_STEP_Y - scroll;
+            if (y + PAGE_HEIGHT > topPos + SURFACE_TOP && y < topPos + SURFACE_BOTTOM) {
+                drawPage(graphics, index, x, y);
+            }
+        }
+        graphics.disableScissor();
+        drawScrollbar(graphics, pageSlots);
+        int hovered = pageAt(mouseX, mouseY);
+        if (!menu.getCarried().isEmpty() && inSurface(mouseX, mouseY)) {
+            graphics.renderItem(menu.getCarried(), mouseX - 8, mouseY - 8);
+        } else if (hovered >= 0 && !menu.getSlot(hovered).getItem().isEmpty()) {
+            ItemStack page = menu.getSlot(hovered).getItem();
+            if (matchesSearch(page)) graphics.renderTooltip(font, page, mouseX, mouseY);
+        } else {
+            renderTooltip(graphics, mouseX, mouseY);
+        }
+    }
+
+    @Override
+    protected void renderBg(GuiGraphics graphics, float partialTick, int mouseX, int mouseY) {
+        graphics.fill(leftPos, topPos + SURFACE_TOP, leftPos + SURFACE_RIGHT,
+                topPos + SURFACE_BOTTOM, 0xB0000000);
+        drawBeveledPanel(graphics, leftPos, topPos + 132, imageWidth, 81);
+        for (int row = 0; row < 3; row++) {
+            for (int column = 0; column < 9; column++) drawSlot(graphics, 7 + column * 18, 134 + row * 18);
+        }
+        for (int column = 0; column < 9; column++) drawSlot(graphics, 7 + column * 18, 192);
+    }
+
+    @Override
+    protected void renderLabels(GuiGraphics graphics, int mouseX, int mouseY) {
+        graphics.drawString(font, playerInventoryTitle, inventoryLabelX, inventoryLabelY, 0x404040, false);
+    }
+
+    @Override
+    public boolean mouseClicked(double mouseX, double mouseY, int button) {
+        if (inScrollbar(mouseX, mouseY) && button == 0) {
+            draggingScrollbar = true;
+            setScrollFromMouse(mouseY, displayedPageSlots());
+            return true;
+        }
+        int index = pageAt(mouseX, mouseY);
+        if (index >= 0 && (button == 0 || button == 1)) {
+            ItemStack page = menu.getSlot(index).getItem();
+            if ((!page.isEmpty() && !matchesSearch(page))
+                    || (page.isEmpty() && !menu.getCarried().is(ModItems.PAGE.get()))) {
+                return true;
+            }
+            setFocused(null);
+            textInput.setFocused(false);
+            selectedSlot = index;
+            slotClicked(menu.getSlot(index), index, button, ClickType.PICKUP);
+            surfaceClickPendingRelease = true;
+            return true;
+        }
+        return super.mouseClicked(mouseX, mouseY, button);
+    }
+
+    @Override
+    public boolean mouseDragged(double mouseX, double mouseY, int button, double dragX, double dragY) {
+        if (draggingScrollbar && button == 0) {
+            setScrollFromMouse(mouseY, displayedPageSlots());
+            return true;
+        }
+        return super.mouseDragged(mouseX, mouseY, button, dragX, dragY);
+    }
+
+    @Override
+    public boolean mouseReleased(double mouseX, double mouseY, int button) {
+        if (draggingScrollbar || surfaceClickPendingRelease) {
+            draggingScrollbar = false;
+            surfaceClickPendingRelease = false;
+            return true;
+        }
+        draggingScrollbar = false;
+        return super.mouseReleased(mouseX, mouseY, button);
+    }
+
+    @Override
+    public boolean mouseScrolled(double mouseX, double mouseY, double scrollX, double scrollY) {
+        if (inSurface(mouseX, mouseY) || inScrollbar(mouseX, mouseY)) {
+            scroll = Math.clamp(scroll - (int)Math.signum(scrollY) * 20,
+                    0, maxScroll(displayedPageSlots()));
+            return true;
+        }
+        return super.mouseScrolled(mouseX, mouseY, scrollX, scrollY);
+    }
+
+    @Override
+    public boolean keyPressed(int keyCode, int scanCode, int modifiers) {
+        if (textInput.isFocused()) {
+            if (keyCode == 256) {
+                setFocused(null);
+                textInput.setFocused(false);
+            } else {
+                textInput.keyPressed(keyCode, scanCode, modifiers);
+            }
+            // EditBox does not consume ordinary letter key presses; the matching charTyped
+            // event handles text input. Do not pass them to the container's inventory keys.
+            return true;
+        }
+        if (!textInput.isFocused() && selectedSlot >= 0 && (keyCode == 263 || keyCode == 262)) {
+            moveSelected(keyCode == 262);
+            return true;
+        }
+        return super.keyPressed(keyCode, scanCode, modifiers);
+    }
+
+    private int displayedPageSlots() {
+        if (menu.getCarried().is(ModItems.PAGE.get())) {
+            return NotebookMenu.NOTEBOOK_SLOTS;
+        }
+        for (int index = NotebookMenu.NOTEBOOK_SLOTS - 1; index >= 0; index--) {
+            if (!menu.getSlot(index).getItem().isEmpty()) {
+                return index + 1;
+            }
+        }
+        return 0;
+    }
+
+    private boolean matchesSearch(ItemStack page) {
+        return textInput.getValue().isBlank()
+                || page.getHoverName().getString().toLowerCase(Locale.ROOT)
+                        .contains(textInput.getValue().toLowerCase(Locale.ROOT));
+    }
+
+    private int pageAt(double mouseX, double mouseY) {
+        if (!inSurface(mouseX, mouseY)) return -1;
+        int localX = (int)mouseX - leftPos;
+        int localY = (int)mouseY - topPos - SURFACE_TOP + scroll;
+        int column = localX / PAGE_STEP_X;
+        int index = (localY / PAGE_STEP_Y) * PAGE_COLUMNS + column;
+        return column < PAGE_COLUMNS && localX % PAGE_STEP_X < PAGE_WIDTH
+                && localY % PAGE_STEP_Y < PAGE_HEIGHT && index < displayedPageSlots()
+                ? index : -1;
+    }
+
+    private boolean inSurface(double mouseX, double mouseY) {
+        return mouseX >= leftPos && mouseX < leftPos + SURFACE_RIGHT
+                && mouseY >= topPos + SURFACE_TOP && mouseY < topPos + SURFACE_BOTTOM;
+    }
+
+    private boolean inScrollbar(double mouseX, double mouseY) {
+        return mouseX >= leftPos + SURFACE_RIGHT && mouseX < leftPos + imageWidth
+                && mouseY >= topPos + SURFACE_TOP && mouseY < topPos + SURFACE_BOTTOM;
+    }
+
+    private int maxScroll(int pageCount) {
+        int rows = (pageCount + PAGE_COLUMNS - 1) / PAGE_COLUMNS;
+        return Math.max(0, rows * PAGE_STEP_Y - (SURFACE_BOTTOM - SURFACE_TOP));
+    }
+
+    private void setScrollFromMouse(double mouseY, int pageCount) {
+        int maximum = maxScroll(pageCount);
+        double fraction = (mouseY - topPos - SURFACE_TOP - 10.0)
+                / (SURFACE_BOTTOM - SURFACE_TOP - 20.0);
+        scroll = Math.clamp((int)(Math.clamp(fraction, 0.0, 1.0) * maximum), 0, maximum);
+    }
+
+    private void drawScrollbar(GuiGraphics graphics, int pageCount) {
+        int x = leftPos + SURFACE_RIGHT;
+        int y = topPos + SURFACE_TOP;
+        int height = SURFACE_BOTTOM - SURFACE_TOP;
+        graphics.fill(x, y, x + 20, y + height, 0xFF858585);
+        graphics.renderOutline(x, y, 20, height, 0xFF262626);
+        for (int line = y + 5; line < y + height - 4; line += 5) {
+            graphics.fill(x + 4, line, x + 16, line + 1, 0xFFB7B7B7);
+        }
+        int maximum = maxScroll(pageCount);
+        int thumbY = y + 4 + (maximum == 0 ? 0 : scroll * (height - 23) / maximum);
+        graphics.fill(x + 4, thumbY, x + 16, thumbY + 15, 0xFFC9C9C9);
+        graphics.renderOutline(x + 4, thumbY, 12, 15, 0xFF414141);
+    }
+
+    private void drawPage(GuiGraphics graphics, int index, int x, int y) {
+        ItemStack page = menu.getSlot(index).getItem();
+        boolean dimmed = page.isEmpty() || !matchesSearch(page);
+        // Legacy's Notebook draws the atlas' native 30x40 page, not a stretched item icon.
+        graphics.blit(PAGE_ATLAS, x, y, PAGE_WIDTH, PAGE_HEIGHT,
+                156, 0, PAGE_WIDTH, PAGE_HEIGHT, 256, 256);
+        if (!page.isEmpty()) {
+            switch (PageItem.content(page).kind()) {
+                case BLANK -> { }
+                case LINK_PANEL -> graphics.fill(x + 5, y + 6, x + 25, y + 20, 0xFF000000);
+                case SYMBOL, UNRESOLVED_SYMBOL -> graphics.blit(symbolTexture(page), x + 1, y + 6,
+                        28, 28, 16, 16, 96, 96, 128, 128);
+            }
+        }
+        if (dimmed) {
+            graphics.fill(x, y, x + PAGE_WIDTH, y + PAGE_HEIGHT, 0xB8000000);
+        }
+        if (index == selectedSlot && !page.isEmpty()) {
+            graphics.renderOutline(x, y, PAGE_WIDTH, PAGE_HEIGHT, 0xFFFFD061);
+        }
+    }
+
+    static ResourceLocation symbolTexture(ItemStack page) {
+        var content = PageItem.content(page);
+        if (content.kind() == net.dnorberg.rivencraft.writing.PageContent.Kind.UNRESOLVED_SYMBOL) {
+            return UNRESOLVED_SYMBOL;
+        }
+        return symbolTexture(content.symbol().orElseThrow().id());
+    }
+
+    static ResourceLocation symbolTexture(ResourceLocation id) {
+        return switch (id.toString()) {
+            case "rivencraft:terrain/standard" -> STANDARD_TERRAIN;
+            case "rivencraft:biome/native" -> NATIVE_BIOMES;
+            case "rivencraft:lighting/normal" -> NORMAL_LIGHTING;
+            case "rivencraft:weather/normal" -> NORMAL_WEATHER;
+            case "rivencraft:celestial/normal_time" -> NORMAL_TIME;
+            case "rivencraft:feature/caves" -> CAVES;
+            default -> GENERIC_SYMBOL;
+        };
+    }
+
+    private static ResourceLocation texture(String path) {
+        return ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "textures/" + path + ".png");
+    }
+
+    private void moveSelected(boolean next) {
+        int target = selectedSlot + (next ? 1 : -1);
+        if (selectedSlot < 0 || target < 0 || target >= NotebookMenu.NOTEBOOK_SLOTS
+                || menu.getSlot(selectedSlot).getItem().isEmpty()) return;
+        int buttonId = (next ? NotebookMenu.MOVE_NEXT_BASE : NotebookMenu.MOVE_PREVIOUS_BASE) + selectedSlot;
+        if (menu.clickMenuButton(minecraft.player, buttonId)) {
+            minecraft.gameMode.handleInventoryButtonClick(menu.containerId, buttonId);
+            selectedSlot = target;
+        }
+    }
+
+    private static void drawBeveledPanel(GuiGraphics graphics, int x, int y, int width, int height) {
+        graphics.fill(x, y, x + width, y + height, 0xFFC6C6C6);
+        graphics.fill(x, y, x + width, y + 2, 0xFFFFFFFF);
+        graphics.fill(x, y, x + 2, y + height, 0xFFFFFFFF);
+        graphics.fill(x, y + height - 2, x + width, y + height, 0xFF555555);
+        graphics.fill(x + width - 2, y, x + width, y + height, 0xFF555555);
+    }
+
+    private void drawSlot(GuiGraphics graphics, int x, int y) {
+        graphics.fill(leftPos + x, topPos + y, leftPos + x + 18, topPos + y + 18, 0xFF8B8B8B);
+        graphics.fill(leftPos + x, topPos + y, leftPos + x + 18, topPos + y + 1, 0xFF373737);
+        graphics.fill(leftPos + x, topPos + y, leftPos + x + 1, topPos + y + 18, 0xFF373737);
+        graphics.fill(leftPos + x + 17, topPos + y, leftPos + x + 18, topPos + y + 18, 0xFFFFFFFF);
+        graphics.fill(leftPos + x, topPos + y + 17, leftPos + x + 18, topPos + y + 18, 0xFFFFFFFF);
+    }
+}

src/main/java/net/dnorberg/rivencraft/client/screen/WritingDeskScreen.java

@@ -0,0 +1,450 @@
+package net.dnorberg.rivencraft.client.screen;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.ArrayList;
+import java.util.Comparator;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import net.minecraft.client.gui.GuiGraphics;
+import net.minecraft.client.gui.components.Button;
+import net.minecraft.client.gui.components.EditBox;
+import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen;
+import net.minecraft.network.chat.Component;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+
+/** Legacy desk atlas layout, with four visible tabs out of the desk's 88 collections. */
+public final class WritingDeskScreen extends AbstractContainerScreen<WritingDeskMenu> {
+    private static final ResourceLocation PAGE_ATLAS = ResourceLocation.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "textures/gui/notebook_pages.png");
+    private static final ResourceLocation LEGACY_DESK = ResourceLocation.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "textures/gui/writing_desk_legacy.png");
+    private static final ResourceLocation SCROLLBAR = ResourceLocation.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "textures/gui/scrollbar.png");
+    private int lastCollection = -1;
+    private int selectedPage;
+    private int scrollRows;
+    private boolean allMode;
+    private boolean sortAlphabetically;
+    private int selectedCollection = -1;
+    private ResourceLocation selectedCategory;
+    private EditBox search;
+    private Button categoryButton;
+    private Button allButton;
+    private Button sortButton;
+    private boolean draggingScrollbar;
+    private record DisplayPage(int collection, int index, ItemStack stack) {}
+    private DisplayPage pageDragSource;
+    private double pageDragStartX;
+    private double pageDragStartY;
+    private boolean draggingPage;
+
+    private boolean isPhysicalPageView() {
+        return !allMode && !sortAlphabetically && selectedCategory == null
+                && (search == null || search.getValue().isBlank());
+    }
+
+    public WritingDeskScreen(WritingDeskMenu menu, Inventory inventory, Component title) {
+        super(menu, inventory, title);
+        imageWidth = 409;
+        imageHeight = 186;
+        titleLabelX = 222;
+    }
+
+    @Override protected void init() {
+        super.init();
+        sortButton = addRenderableWidget(Button.builder(Component.literal("AZ"), button -> {
+            sortAlphabetically = !sortAlphabetically;
+            scrollRows = 0;
+        }).bounds(leftPos + 58, topPos, 20, 18).build());
+        allButton = addRenderableWidget(Button.builder(Component.literal("ALL"), button -> {
+            allMode = !allMode;
+            scrollRows = 0;
+            if (!allMode) {
+                selectedCollection = -1;
+                selectedPage = 0;
+                if (minecraft != null && minecraft.gameMode != null)
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId, WritingDeskMenu.PAGE_BUTTON_BASE);
+            }
+        }).bounds(leftPos + 80, topPos, 28, 18).build());
+        search = new EditBox(font, leftPos + 110, topPos, 101, 18,
+                Component.translatable("screen.rivencraft.writing_desk.search"));
+        search.setMaxLength(64);
+        search.setHint(Component.translatable("screen.rivencraft.writing_desk.search"));
+        search.setResponder(value -> scrollRows = 0);
+        addRenderableWidget(search);
+        categoryButton = addRenderableWidget(Button.builder(Component.literal("C"), button -> {
+            List<ResourceLocation> categories = menu.catalog().stream()
+                    .map(SymbolDisplayMetadata::category).distinct().sorted().toList();
+            int next = selectedCategory == null ? 0 : categories.indexOf(selectedCategory) + 1;
+            selectedCategory = next >= categories.size() ? null : categories.get(next);
+            categoryButton.setMessage(Component.literal(selectedCategory == null ? "C" : "C*"));
+            scrollRows = 0;
+        }).bounds(leftPos + 213, topPos, 18, 18).build());
+    }
+
+    private List<DisplayPage> filteredPages() {
+        String query = search == null ? "" : search.getValue().trim().toLowerCase(Locale.ROOT);
+        List<DisplayPage> entries = new ArrayList<>();
+        int from = allMode ? 0 : menu.activeCollection();
+        int until = allMode ? WritingDeskBlockEntity.COLLECTIONS : from + 1;
+        for (int collection = from; collection < until; collection++) {
+            List<ItemStack> pages = pages(collection);
+            int last = -1;
+            for (int i = 0; i < pages.size(); i++) if (!pages.get(i).isEmpty()) last = i;
+            // A notebook has exactly its normal GUI capacity; a loose page has one position.
+            if (isPhysicalPageView()) last = menu.pageCapacity(collection) - 1;
+            for (int i = 0; i <= last; i++) {
+                ItemStack page = i < pages.size() ? pages.get(i) : ItemStack.EMPTY;
+                if (page.isEmpty() && (allMode || sortAlphabetically || !query.isEmpty() || selectedCategory != null)) continue;
+                if (!page.isEmpty() && !query.isEmpty()
+                        && !page.getHoverName().getString().toLowerCase(Locale.ROOT).contains(query)
+                        && !PageItem.content(page).symbol().map(symbol -> symbol.id().toString()
+                        .toLowerCase(Locale.ROOT).contains(query)).orElse(false)) continue;
+                if (!page.isEmpty() && selectedCategory != null) {
+                    ResourceLocation id = PageItem.content(page).symbol().map(symbol -> symbol.id()).orElse(null);
+                    if (menu.catalog().stream().noneMatch(metadata -> metadata.id().equals(id)
+                            && metadata.category().equals(selectedCategory))) continue;
+                }
+                entries.add(new DisplayPage(collection, i, page));
+            }
+        }
+        if (sortAlphabetically) entries.sort(Comparator
+                .comparing((DisplayPage entry) -> entry.stack().getHoverName().getString(), String.CASE_INSENSITIVE_ORDER)
+                .thenComparingInt(DisplayPage::collection).thenComparingInt(DisplayPage::index));
+        return entries;
+    }
+
+    @Override public void renderBackground(GuiGraphics graphics, int mouseX, int mouseY, float partialTick) {
+        // Keep the world visible, but still draw our GUI backing. The vanilla
+        // container implementation normally calls renderBg from this method.
+        renderBg(graphics, partialTick, mouseX, mouseY);
+    }
+
+    @Override protected void renderBg(GuiGraphics graphics, float partialTick, int mouseX, int mouseY) {
+        int x = leftPos;
+        int y = topPos;
+        // Legacy GuiWritingDesk draws the entire 176x166 panel, not a stretched swatch.
+        graphics.blit(LEGACY_DESK, x + 233, y + 20, 0, 0, 176, 166);
+        drawTabControl(graphics, 20, 203, menu.firstVisibleTab() > 0);
+        for (int i = 0; i < 4; i++) {
+            int tab = menu.firstVisibleTab() + i;
+            int tabY = y + 29 + i * 37;
+            if (tab == menu.activeCollection() && !allMode) graphics.setColor(0.5F, 0.5F, 1F, 1F);
+            graphics.blit(LEGACY_DESK, x, tabY, 0, 166, 58, 37);
+            graphics.setColor(1F, 1F, 1F, 1F);
+            graphics.drawString(font, Integer.toString(tab + 1), x + 8, tabY + 8, 0xFF181818, false);
+            ItemStack collection = menu.getSlot(tab).getItem();
+            if (!collection.isEmpty()) {
+                String name = collection.getHoverName().getString();
+                float scale = Math.min(1F, 50F / Math.max(1, font.width(name)));
+                graphics.pose().pushPose();
+                graphics.pose().translate(x + 4, tabY + 25, 0);
+                graphics.pose().scale(scale, scale, 1);
+                graphics.drawString(font, name, 0, 0, 0xFF404040, false);
+                graphics.pose().popPose();
+            }
+        }
+        drawTabControl(graphics, 177, 212, menu.firstVisibleTab() < WritingDeskBlockEntity.COLLECTIONS - 4);
+        // GuiElementVSlider: 4-pixel caps, repeated 22-pixel track, 12x15 thumb.
+        graphics.blit(SCROLLBAR, x + 213, y + 20, 0, 0, 20, 4, 32, 32);
+        for (int offset = 4; offset < 162; offset += 22)
+            graphics.blit(SCROLLBAR, x + 213, y + 20 + offset, 0, 4, 20, Math.min(22, 162 - offset), 32, 32);
+        graphics.blit(SCROLLBAR, x + 213, y + 182, 0, 26, 20, 4, 32, 32);
+        int totalRows = (filteredPages().size() + 4) / 5;
+        int maxScroll = Math.max(0, totalRows - 4);
+        scrollRows = Math.clamp(scrollRows, 0, maxScroll);
+        int thumbY = y + 24 + (maxScroll == 0 ? 0 : scrollRows * 143 / maxScroll);
+        graphics.blit(SCROLLBAR, x + 217, thumbY, 20, draggingScrollbar ? 15 : 0, 12, 15, 32, 32);
+        graphics.fill(x + 365, y + 27, x + 381, y + 97, 0xFF303035);
+        graphics.fill(x + 366, y + 28, x + 380, y + 96, 0xFF6666AA);
+        int filled = 68 * menu.inkRemaining() / 16;
+        if (filled > 0) graphics.fill(x + 366, y + 96 - filled, x + 380, y + 96, 0xFF15151B);
+    }
+
+    private void drawTabControl(GuiGraphics graphics, int y, int textureY, boolean enabled) {
+        if (!enabled) graphics.setColor(0.4F, 0.4F, 0.4F, 1F);
+        graphics.blit(LEGACY_DESK, leftPos, topPos + y, 0, textureY, 58, 9);
+        graphics.setColor(1F, 1F, 1F, 1F);
+    }
+
+    @Override protected void renderLabels(GuiGraphics graphics, int mouseX, int mouseY) {
+        // Legacy leaves the inventory grid unlabeled.
+    }
+
+    @Override public void render(GuiGraphics graphics, int mouseX, int mouseY, float partialTick) {
+        super.render(graphics, mouseX, mouseY, partialTick);
+        if (sortAlphabetically) graphics.renderOutline(leftPos + 58, topPos, 20, 18, 0xFFFFD061);
+        if (allMode) graphics.renderOutline(leftPos + 80, topPos, 28, 18, 0xFFFFD061);
+        renderCollection(graphics);
+        if (draggingPage && pageDragSource != null) {
+            DisplayPage target = pageAtMouse(mouseX, mouseY);
+            if (target != null && canMovePage(pageDragSource, target)) {
+                int x = leftPos + 58 + ((int) mouseX - leftPos - 58) / 31 * 31;
+                int y = topPos + 20 + ((int) mouseY - topPos - 20) / 41 * 41;
+                graphics.renderOutline(x, y, 30, 40, 0xFF57D478);
+            }
+            graphics.renderItem(pageDragSource.stack(), mouseX - 8, mouseY - 8);
+        }
+        renderTooltip(graphics, mouseX, mouseY);
+        if (mouseX >= leftPos + 365 && mouseX < leftPos + 381
+                && mouseY >= topPos + 27 && mouseY < topPos + 97) {
+            graphics.renderTooltip(font, Component.translatable("screen.rivencraft.writing_desk.ink",
+                    menu.inkRemaining(), 16), mouseX, mouseY);
+        }
+        if (mouseX >= leftPos + 213 && mouseX < leftPos + 231
+                && mouseY >= topPos && mouseY < topPos + 18) {
+            graphics.renderTooltip(font, Component.literal(selectedCategory == null
+                    ? "All categories" : selectedCategory.toString()), mouseX, mouseY);
+        }
+    }
+
+    private List<ItemStack> pages(int collectionIndex) {
+        ItemStack collection = menu.getSlot(collectionIndex).getItem();
+        if (collection.is(ModItems.PAGE.get())) return List.of(collection);
+        if (collection.is(ModItems.NOTEBOOK.get())) {
+            return collection.getOrDefault(ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+        }
+        return List.of();
+    }
+
+    private void renderCollection(GuiGraphics graphics) {
+        if (lastCollection != menu.activeCollection()) {
+            lastCollection = menu.activeCollection();
+            scrollRows = 0;
+            selectedPage = 0;
+            selectedCollection = -1;
+        }
+        List<DisplayPage> entries = filteredPages();
+        for (int i = scrollRows * 5; i < entries.size() && i < scrollRows * 5 + 20; i++) {
+            int column = i % 5;
+            int row = i / 5 - scrollRows;
+            DisplayPage entry = entries.get(i);
+            ItemStack page = entry.stack();
+            int x = leftPos + 58 + column * 31;
+            int y = topPos + 20 + row * 41;
+            drawPage(graphics, page, x, y);
+            if (page.isEmpty()) graphics.fill(x, y, x + 30, y + 40, 0xB8000000);
+            int active = selectedCollection >= 0 ? selectedCollection : menu.activeCollection();
+            if (entry.collection() == active && entry.index() == selectedPage && !page.isEmpty())
+                graphics.renderOutline(x, y, 30, 40, 0xFFFFD061);
+        }
+        int active = selectedCollection >= 0 ? selectedCollection : menu.activeCollection();
+        List<ItemStack> source = pages(active);
+        if (selectedPage >= source.size() || source.get(selectedPage).isEmpty()) return;
+        ItemStack selected = source.get(selectedPage);
+        drawPage(graphics, selected, leftPos + 265, topPos + 26);
+        String title = font.plainSubstrByWidth(selected.getHoverName().getString(), 95);
+        graphics.fill(leftPos + 261, topPos + 81, leftPos + 360, topPos + 95, 0xFF202020);
+        graphics.drawString(font, title, leftPos + 263, topPos + 84, 0xFFE0E0E0, false);
+    }
+
+    private void drawPage(GuiGraphics graphics, ItemStack page, int x, int y) {
+        graphics.blit(PAGE_ATLAS, x, y, 30, 40, 156, 0, 30, 40, 256, 256);
+        if (page.isEmpty()) return;
+        switch (PageItem.content(page).kind()) {
+            case BLANK -> { }
+            case LINK_PANEL -> graphics.fill(x + 5, y + 6, x + 25, y + 20, 0xFF000000);
+            case SYMBOL, UNRESOLVED_SYMBOL -> graphics.blit(NotebookScreen.symbolTexture(page), x + 1, y + 6,
+                    28, 28, 16, 16, 96, 96, 128, 128);
+        }
+    }
+
+    private DisplayPage pageAtMouse(double mouseX, double mouseY) {
+        int x = (int) Math.floor(mouseX - leftPos - 58);
+        int y = (int) Math.floor(mouseY - topPos - 20);
+        if (x < 0 || x >= 155 || y < 0 || y >= 164 || x % 31 >= 30 || y % 41 >= 40) return null;
+        int index = (y / 41 + scrollRows) * 5 + x / 31;
+        List<DisplayPage> entries = filteredPages();
+        return index < entries.size() ? entries.get(index) : null;
+    }
+
+    private boolean canMovePage(DisplayPage source, DisplayPage target) {
+        return !source.stack().isEmpty()
+                && (menu.getSlot(source.collection()).getItem().is(ModItems.NOTEBOOK.get())
+                    || menu.getSlot(source.collection()).getItem().is(ModItems.PAGE.get()))
+                && (menu.getSlot(target.collection()).getItem().is(ModItems.NOTEBOOK.get())
+                    || menu.getSlot(target.collection()).getItem().is(ModItems.PAGE.get()))
+                && (source.collection() != target.collection() || source.index() != target.index());
+    }
+
+    private int extractTargetSlot(double mouseX, double mouseY) {
+        for (Slot slot : menu.slots) {
+            int index = slot.index;
+            if (index >= WritingDeskBlockEntity.COLLECTIONS && index <= WritingDeskMenu.COPY_RESULT) continue;
+            if (!slot.isActive() || !isHovering(slot.x, slot.y, 16, 16, mouseX, mouseY)) continue;
+            ItemStack held = pageDragSource.stack();
+            if (!slot.mayPlace(held)) return -1;
+            ItemStack current = slot.getItem();
+            if (current.isEmpty()) return index;
+            if (index < WritingDeskBlockEntity.COLLECTIONS && current.is(ModItems.NOTEBOOK.get())) {
+                List<ItemStack> pages = current.getOrDefault(
+                        ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+                if (pages.size() < NotebookContents.MAX_PAGES || pages.stream().anyMatch(ItemStack::isEmpty))
+                    return index;
+            } else if (index > WritingDeskMenu.COPY_RESULT && ItemStack.isSameItemSameComponents(current, held)
+                    && current.getCount() < slot.getMaxStackSize(held)) return index;
+            return -1;
+        }
+        return -1;
+    }
+
+    @Override public boolean mouseClicked(double mouseX, double mouseY, int button) {
+        if (button == 0) {
+            pageDragSource = null;
+            draggingPage = false;
+        }
+        int surfaceX = (int) Math.floor(mouseX - leftPos - 58);
+        int surfaceY = (int) Math.floor(mouseY - topPos - 20);
+        if ((button == 0 || button == 1) && !menu.getCarried().isEmpty()
+                && surfaceX >= 0 && surfaceX < 155 && surfaceY >= 0 && surfaceY < 164) {
+            if (menu.getCarried().is(ModItems.PAGE.get()) && surfaceX % 31 < 30 && surfaceY % 41 < 40) {
+                int index = (surfaceY / 41 + scrollRows) * 5 + surfaceX / 31;
+                List<DisplayPage> entries = filteredPages();
+                // Only displayed positions are addressable. Filtering never turns
+                // empty screen space into additional storage for a loose-page tab.
+                int collection = index < entries.size() ? entries.get(index).collection() : menu.activeCollection();
+                int page = index < entries.size() ? entries.get(index).index() : index;
+                if (index < entries.size() && page < menu.pageCapacity(collection)
+                        && minecraft != null && minecraft.gameMode != null) {
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + collection * NotebookContents.MAX_PAGES + page);
+                }
+            }
+            return true;
+        }
+        if (button == 0) {
+            if (mouseX >= leftPos && mouseX < leftPos + 58) {
+                int y = (int) mouseY - topPos;
+                if (y >= 20 && y < 29 || y >= 177 && y < 186) {
+                    if (minecraft != null && minecraft.gameMode != null)
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                                y < 29 ? WritingDeskMenu.PREVIOUS_TABS : WritingDeskMenu.NEXT_TABS);
+                    return true;
+                }
+            }
+            if (mouseX >= leftPos + 213 && mouseX < leftPos + 233
+                    && mouseY >= topPos + 20 && mouseY < topPos + 186) {
+                draggingScrollbar = true;
+                setScrollFromMouse(mouseY);
+                return true;
+            }
+            int x = (int) Math.floor(mouseX - leftPos - 58);
+            int y = (int) Math.floor(mouseY - topPos - 20);
+            if (x >= 0 && x < 155 && y >= 0 && y < 164) {
+                DisplayPage entry = pageAtMouse(mouseX, mouseY);
+                if (entry != null && !entry.stack().isEmpty()) {
+                    selectedCollection = entry.collection();
+                    selectedPage = entry.index();
+                    if (menu.getCarried().isEmpty()) {
+                        pageDragSource = entry;
+                        pageDragStartX = mouseX;
+                        pageDragStartY = mouseY;
+                    }
+                    if (minecraft != null && minecraft.gameMode != null) {
+                        int id = WritingDeskMenu.ALL_PAGE_BUTTON_BASE
+                                + entry.collection() * NotebookContents.MAX_PAGES + entry.index();
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId, id);
+                    }
+                }
+                return true;
+            }
+        }
+        if (button == 0 && mouseX >= leftPos && mouseX < leftPos + 58) {
+            for (int i = 0; i < 4; i++) {
+                int top = topPos + 29 + i * 37;
+                boolean overSlot = mouseX >= leftPos + 36 && mouseX < leftPos + 54
+                        && mouseY >= top + 4 && mouseY < top + 22;
+                if (mouseY >= top && mouseY < top + 37 && !overSlot) {
+                    allMode = false;
+                    selectedCollection = -1;
+                    if (minecraft != null && minecraft.gameMode != null) {
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId, menu.firstVisibleTab() + i);
+                    }
+                    return true;
+                }
+            }
+        }
+        return super.mouseClicked(mouseX, mouseY, button);
+    }
+
+    @Override public boolean mouseScrolled(double mouseX, double mouseY, double scrollX, double scrollY) {
+        if (mouseX >= leftPos + 58 && mouseX < leftPos + 233
+                && mouseY >= topPos + 20 && mouseY < topPos + 186) {
+            int rows = (filteredPages().size() + 4) / 5;
+            scrollRows = Math.clamp(scrollRows - (int) Math.signum(scrollY), 0, Math.max(0, rows - 4));
+            return true;
+        }
+        return super.mouseScrolled(mouseX, mouseY, scrollX, scrollY);
+    }
+
+    private void setScrollFromMouse(double mouseY) {
+        int rows = (filteredPages().size() + 4) / 5;
+        int max = Math.max(0, rows - 4);
+        scrollRows = Math.clamp((int) Math.round((mouseY - topPos - 31.5) * max / 143.0), 0, max);
+    }
+
+    @Override public boolean mouseDragged(double mouseX, double mouseY, int button, double dragX, double dragY) {
+        if (button == 0 && pageDragSource != null) {
+            if (Math.abs(mouseX - pageDragStartX) >= 4 || Math.abs(mouseY - pageDragStartY) >= 4)
+                draggingPage = true;
+            return true;
+        }
+        if (button == 0 && draggingScrollbar) {
+            setScrollFromMouse(mouseY);
+            return true;
+        }
+        return super.mouseDragged(mouseX, mouseY, button, dragX, dragY);
+    }
+
+    @Override public boolean mouseReleased(double mouseX, double mouseY, int button) {
+        if (button == 0 && pageDragSource != null) {
+            if (draggingPage) {
+                DisplayPage target = pageAtMouse(mouseX, mouseY);
+                if (target != null && canMovePage(pageDragSource, target)
+                        && minecraft != null && minecraft.gameMode != null) {
+                    selectedCollection = target.collection();
+                    selectedPage = target.index();
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.movePageButtonId(pageDragSource.collection(), pageDragSource.index(),
+                                    target.collection(), target.index()));
+                } else if (target == null && minecraft != null && minecraft.gameMode != null) {
+                    int targetSlot = extractTargetSlot(mouseX, mouseY);
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.extractPageButtonId(pageDragSource.collection(), pageDragSource.index(),
+                                    targetSlot));
+                }
+            }
+            pageDragSource = null;
+            draggingPage = false;
+            return true;
+        }
+        if (button == 0 && draggingScrollbar) {
+            draggingScrollbar = false;
+            return true;
+        }
+        return super.mouseReleased(mouseX, mouseY, button);
+    }
+
+    @Override public boolean keyPressed(int keyCode, int scanCode, int modifiers) {
+        if (search != null && search.isFocused()) {
+            if (keyCode == 256) {
+                setFocused(null);
+                search.setFocused(false);
+            } else {
+                search.keyPressed(keyCode, scanCode, modifiers);
+            }
+            return true;
+        }
+        return super.keyPressed(keyCode, scanCode, modifiers);
+    }
+}

src/main/java/net/dnorberg/rivencraft/compat/PreviewBackendSelector.java

@@ -0,0 +1,30 @@
+package net.dnorberg.rivencraft.compat;
+
+import net.dnorberg.rivencraft.config.RivencraftClientConfig;
+
+/** Pure selection policy for optional destination preview integrations. */
+public final class PreviewBackendSelector {
+    public enum Backend {
+        IMMERSIVE_PORTALS,
+        PONDER,
+        LEGACY
+    }
+
+    private PreviewBackendSelector() {
+    }
+
+    public static Backend select(
+            RivencraftClientConfig.PreviewMode mode,
+            boolean immersivePortalsAvailable,
+            boolean ponderAvailable
+    ) {
+        return switch (mode) {
+            case AUTO -> immersivePortalsAvailable
+                    ? Backend.IMMERSIVE_PORTALS
+                    : ponderAvailable ? Backend.PONDER : Backend.LEGACY;
+            case IMMERSIVE_PORTALS -> immersivePortalsAvailable ? Backend.IMMERSIVE_PORTALS : Backend.LEGACY;
+            case PONDER -> ponderAvailable ? Backend.PONDER : Backend.LEGACY;
+            case LEGACY -> Backend.LEGACY;
+        };
+    }
+}

src/main/java/net/dnorberg/rivencraft/config/RivencraftConfig.java

@@ -15,6 +15,8 @@ public final class RivencraftConfig {
 
     public static final ModConfigSpec SPEC;
     private static final ModConfigSpec.EnumValue<ReturnLinkMode> RETURN_LINK_MODE;
+    private static final ModConfigSpec.IntValue SYMBOL_INK_COST;
+    private static final ModConfigSpec.IntValue LINK_PANEL_INK_COST;
 
     static {
         ModConfigSpec.Builder builder = new ModConfigSpec.Builder();
@@ -25,6 +27,12 @@ public final class RivencraftConfig {
                 )
                 .defineEnum("return_link_mode", ReturnLinkMode.ON_CREATION);
         builder.pop();
+        builder.push("writing");
+        SYMBOL_INK_COST = builder.comment("Ink units consumed when the Writing Desk copies one symbol page.")
+                .defineInRange("symbol_ink_cost", 1, 1, 16);
+        LINK_PANEL_INK_COST = builder.comment("Ink units consumed when preparing one baseline link-panel page.")
+                .defineInRange("link_panel_ink_cost", 2, 1, 16);
+        builder.pop();
         SPEC = builder.build();
     }
 
@@ -34,4 +42,12 @@ public final class RivencraftConfig {
     public static ReturnLinkMode returnLinkMode() {
         return RETURN_LINK_MODE.get();
     }
+
+    public static int symbolInkCost() {
+        return SYMBOL_INK_COST.get();
+    }
+
+    public static int linkPanelInkCost() {
+        return LINK_PANEL_INK_COST.get();
+    }
 }

src/main/java/net/dnorberg/rivencraft/gametest/LinkingGameTests.java

@@ -12,6 +12,8 @@ import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.LinkingService;
 import net.dnorberg.rivencraft.book.AgeVisitSavedData;
 import net.dnorberg.rivencraft.book.AgeTraits;
+import net.dnorberg.rivencraft.compat.PreviewBackendSelector;
+import net.dnorberg.rivencraft.config.RivencraftClientConfig;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
 import net.dnorberg.rivencraft.item.LinkingBookItem;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
@@ -40,6 +42,53 @@ public final class LinkingGameTests {
     private LinkingGameTests() {
     }
 
+    @GameTest(template = "empty")
+    public static void previewBackendSelectionCoversOptionalDependencyMatrix(GameTestHelper helper) {
+        assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.AUTO, true, true,
+                PreviewBackendSelector.Backend.IMMERSIVE_PORTALS);
+        assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.AUTO, true, false,
+                PreviewBackendSelector.Backend.IMMERSIVE_PORTALS);
+        assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.AUTO, false, true,
+                PreviewBackendSelector.Backend.PONDER);
+        assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.AUTO, false, false,
+                PreviewBackendSelector.Backend.LEGACY);
+
+        for (boolean ponderAvailable : new boolean[] {false, true}) {
+            assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.IMMERSIVE_PORTALS, true,
+                    ponderAvailable, PreviewBackendSelector.Backend.IMMERSIVE_PORTALS);
+            assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.IMMERSIVE_PORTALS, false,
+                    ponderAvailable, PreviewBackendSelector.Backend.LEGACY);
+        }
+        for (boolean immersivePortalsAvailable : new boolean[] {false, true}) {
+            assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.PONDER,
+                    immersivePortalsAvailable, true, PreviewBackendSelector.Backend.PONDER);
+            assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.PONDER,
+                    immersivePortalsAvailable, false, PreviewBackendSelector.Backend.LEGACY);
+        }
+        for (boolean immersivePortalsAvailable : new boolean[] {false, true}) {
+            for (boolean ponderAvailable : new boolean[] {false, true}) {
+                assertPreviewBackend(helper, RivencraftClientConfig.PreviewMode.LEGACY,
+                        immersivePortalsAvailable, ponderAvailable, PreviewBackendSelector.Backend.LEGACY);
+            }
+        }
+        helper.succeed();
+    }
+
+    private static void assertPreviewBackend(
+            GameTestHelper helper,
+            RivencraftClientConfig.PreviewMode mode,
+            boolean immersivePortalsAvailable,
+            boolean ponderAvailable,
+            PreviewBackendSelector.Backend expected
+    ) {
+        helper.assertValueEqual(
+                PreviewBackendSelector.select(mode, immersivePortalsAvailable, ponderAvailable),
+                expected,
+                mode + " selection with Immersive Portals=" + immersivePortalsAvailable
+                        + " and Ponder=" + ponderAvailable
+        );
+    }
+
     @GameTest(template = "empty")
     public static void dataPackAgeProfilesResolveRegisteredResources(GameTestHelper helper) {
         var registries = helper.getLevel().registryAccess();
@@ -192,6 +241,78 @@ public final class LinkingGameTests {
         });
     }
 
+    @GameTest(template = "empty", timeoutTicks = 400)
+    public static void everyTerrainProfileProvidesSafeArrivalAndReturnTravel(GameTestHelper helper) {
+        ServerPlayer player = helper.makeMockServerPlayerInLevel();
+        BlockPos returnPosition = player.blockPosition();
+        helper.getLevel().setBlock(returnPosition.below(), Blocks.STONE.defaultBlockState(), 2);
+        helper.getLevel().setBlock(returnPosition, Blocks.AIR.defaultBlockState(), 2);
+        helper.getLevel().setBlock(returnPosition.above(), Blocks.AIR.defaultBlockState(), 2);
+        LinkTarget returnTarget = new LinkTarget(
+                GlobalPos.of(helper.getLevel().dimension(), returnPosition),
+                player.getYRot(),
+                player.getXRot()
+        );
+        long worldSeed = helper.getLevel().getServer().overworld().getSeed();
+        runTerrainProfileTravel(helper, player, returnTarget, AgeGenerationProfiles.all(), 0, worldSeed);
+    }
+
+    private static void runTerrainProfileTravel(
+            GameTestHelper helper,
+            ServerPlayer player,
+            LinkTarget returnTarget,
+            java.util.List<net.minecraft.resources.ResourceLocation> profiles,
+            int index,
+            long worldSeed
+    ) {
+        if (index >= profiles.size()) {
+            helper.succeed();
+            return;
+        }
+        var profile = profiles.get(index);
+        AgeReference reference = referenceSelectingProfile(profile, worldSeed);
+        LinkTarget destination = AgeDimensionService.resolve(player, reference).orElse(null);
+        helper.assertTrue(destination != null, profile + " must create a destination");
+        if (destination == null) {
+            return;
+        }
+        helper.runAfterDelay(1, () -> {
+            AgeDefinition definition = AgeRegistrySavedData.get(helper.getLevel()).find(reference.id()).orElseThrow();
+            helper.assertValueEqual(definition.generationProfile(), profile,
+                    "The acceptance fixture must select " + profile);
+            var ageLevel = player.getServer().getLevel(destination.location().dimension());
+            helper.assertTrue(ageLevel != null, profile + " must create a loaded runtime dimension");
+            BlockPos spawn = destination.location().pos();
+            helper.assertTrue(ageLevel != null && ageLevel.getBlockState(spawn.below()).is(Blocks.COBBLESTONE),
+                    profile + " must create a solid arrival platform");
+            helper.assertTrue(ageLevel != null && ageLevel.getBlockState(spawn).isAir()
+                            && ageLevel.getBlockState(spawn.above()).isAir(),
+                    profile + " must create clear arrival headroom");
+            helper.assertValueEqual(LinkingService.travelWithFooting(player, destination),
+                    LinkingService.LinkResult.SUCCESS, profile + " must accept safe inbound travel");
+            helper.assertValueEqual(LinkingService.travel(player, returnTarget),
+                    LinkingService.LinkResult.SUCCESS, profile + " must permit return travel");
+            helper.runAfterDelay(1, () -> runTerrainProfileTravel(
+                    helper, player, returnTarget, profiles, index + 1, worldSeed));
+        });
+    }
+
+    private static AgeReference referenceSelectingProfile(
+            net.minecraft.resources.ResourceLocation profile,
+            long worldSeed
+    ) {
+        UUID id = UUID.randomUUID();
+        for (int candidate = 0; candidate < 100_000; candidate++) {
+            String name = "Profile Acceptance " + profile.getPath() + " " + id + " " + candidate;
+            var dimension = AgeDefinition.namedDimensionId(name);
+            long seed = worldSeed + dimension.hashCode();
+            if (AgeRuntimeProfiles.select(seed).equals(profile)) {
+                return new AgeReference(id, name);
+            }
+        }
+        throw new IllegalStateException("Could not select profile " + profile);
+    }
+
     @GameTest(template = "empty", timeoutTicks = 100)
     public static void unloadedAgeReloadsWithTheSameDefinition(GameTestHelper helper) {
         UUID id = UUID.randomUUID();
@@ -480,7 +601,9 @@ public final class LinkingGameTests {
         }
         helper.assertTrue(level.getChunkSource().getGenerator().getBiomeSource().possibleBiomes().stream().allMatch(holder -> holder.is(biome)),
                 "The material test Age must select " + biome.location());
-        // Sample away from the generated arrival platform around the Age spawn.
+        // Sample away from the generated arrival platform. Vanilla surface rules
+        // can place a shallow local patch such as gravel over the biome's base block.
+        boolean foundExpectedSurface = false;
         int sampleX = 64;
         int sampleZ = 64;
         level.getChunk(sampleX >> 4, sampleZ >> 4);
@@ -489,10 +612,15 @@ public final class LinkingGameTests {
                 sampleX,
                 sampleZ
         ) - 1;
-        var surfaceState = level.getBlockState(new BlockPos(sampleX, surfaceY, sampleZ));
+        for (int depth = 0; depth <= 8; depth++) {
-        helper.assertTrue(surfaceState.is(expectedBlock),
+            if (level.getBlockState(new BlockPos(sampleX, surfaceY - depth, sampleZ)).is(expectedBlock)) {
+                foundExpectedSurface = true;
+                break;
+            }
+        }
+        helper.assertTrue(foundExpectedSurface,
                 biome.location() + " terrain must expose " + expectedBlock.getDescriptionId()
-                        + " at the surface, found " + surfaceState);
+                        + " across the sampled surface");
     }
 
     @GameTest(template = "empty")

src/main/java/net/dnorberg/rivencraft/gametest/WritingDataGameTests.java

@@ -0,0 +1,321 @@
+package net.dnorberg.rivencraft.gametest;
+
+import com.mojang.serialization.JsonOps;
+import io.netty.buffer.Unpooled;
+import java.util.List;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.writing.OrderedWriting;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.dnorberg.rivencraft.writing.WritingEntry;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.item.InkVialItem;
+import net.dnorberg.rivencraft.writing.WritingInkService;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.menu.NotebookMenu;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.inventory.ClickType;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+/** Acceptance coverage for Milestone 4's persistent writing contracts. */
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class WritingDataGameTests {
+    private WritingDataGameTests() {
+    }
+
+    @GameTest(template = "empty")
+    public static void orderedWritingPreservesKnownUnknownAndLinkPanelEntries(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:removed_symbol");
+        OrderedWriting original = new OrderedWriting(List.of(
+                WritingEntry.symbol(known),
+                WritingEntry.symbol(unknown),
+                WritingEntry.linkPanel()
+        ));
+
+        var json = OrderedWriting.CODEC.encodeStart(JsonOps.INSTANCE, original).result().orElseThrow();
+        OrderedWriting persistentCopy = OrderedWriting.CODEC.parse(JsonOps.INSTANCE, json).result().orElseThrow();
+        helper.assertValueEqual(persistentCopy, original,
+                "Persistent writing codec must retain entry order and unknown symbol IDs");
+
+        FriendlyByteBuf buffer = new FriendlyByteBuf(Unpooled.buffer());
+        OrderedWriting.STREAM_CODEC.encode(buffer, original);
+        OrderedWriting networkCopy = OrderedWriting.STREAM_CODEC.decode(buffer);
+        helper.assertValueEqual(networkCopy, original,
+                "Network writing codec must retain entry order and unknown symbol IDs");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void serverCatalogResolvesBuiltinsAndKeepsUnknownReferencesReadable(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:removed_symbol");
+        helper.assertTrue(SymbolCatalog.symbols().size() >= 6,
+                "The built-in catalog must exercise every Milestone 4 writing workflow");
+        helper.assertTrue(SymbolCatalog.isKnown(known),
+                "The built-in Standard Terrain symbol must be server-authoritative");
+        helper.assertFalse(SymbolCatalog.isKnown(unknown),
+                "An absent data-pack symbol must remain unresolved");
+        var unresolved = SymbolCatalog.display(unknown);
+        helper.assertFalse(unresolved.resolved(),
+                "Unknown symbol display metadata must be marked unresolved");
+        helper.assertValueEqual(unresolved.id(), unknown.id(),
+                "Unresolved display metadata must preserve the original namespaced ID");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void pageStatesPersistAndNetworkRoundTrip(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference removed = reference("example:removed_symbol");
+        List<PageContent> states = List.of(
+                PageContent.BLANK,
+                PageContent.symbol(known),
+                PageContent.unresolved(removed),
+                PageContent.LINK_PANEL
+        );
+
+        for (PageContent state : states) {
+            var json = PageContent.CODEC.encodeStart(JsonOps.INSTANCE, state).result().orElseThrow();
+            PageContent persistentCopy = PageContent.CODEC.parse(JsonOps.INSTANCE, json).result().orElseThrow();
+            helper.assertValueEqual(persistentCopy, state, "Page content must persist exactly");
+
+            FriendlyByteBuf buffer = new FriendlyByteBuf(Unpooled.buffer());
+            PageContent.STREAM_CODEC.encode(buffer, state);
+            helper.assertValueEqual(PageContent.STREAM_CODEC.decode(buffer), state,
+                    "Page content must network-sync exactly");
+        }
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void pageItemPreservesContentAndRejectsForgedUnknownSymbols(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:forged_symbol");
+        ItemStack page = PageItem.createSymbolPage(known);
+        CompoundTag serialized = (CompoundTag) page.saveOptional(helper.getLevel().registryAccess());
+        ItemStack restored = ItemStack.parseOptional(helper.getLevel().registryAccess(), serialized);
+        helper.assertValueEqual(restored.get(ModDataComponents.PAGE_CONTENT.get()), PageContent.symbol(known),
+                "Symbol page content must survive an ItemStack save/load");
+        helper.assertValueEqual(
+                restored.get(ModDataComponents.PAGE_SYMBOL_DISPLAY.get()),
+                SymbolCatalog.display(known),
+                "Server-selected display metadata must survive for remote clients"
+        );
+
+        ItemStack recovered = PageItem.createRecoveredPage(unknown);
+        helper.assertFalse(PageItem.isUsableWriting(recovered),
+                "An unresolved page must remain recoverable without becoming valid writing");
+        try {
+            PageItem.createSymbolPage(unknown);
+            helper.fail("The server must reject new pages for unknown symbols");
+        } catch (IllegalArgumentException expected) {
+            helper.succeed();
+        }
+    }
+
+    @GameTest(template = "empty")
+    public static void notebookContentsPreserveOrderGapsNamesAndUnknownPages(GameTestHelper helper) {
+        ItemStack first = PageItem.createSymbolPage(reference("rivencraft:terrain/standard"));
+        first.set(net.minecraft.core.component.DataComponents.CUSTOM_NAME,
+                net.minecraft.network.chat.Component.literal("Foundation"));
+        ItemStack unknown = PageItem.createRecoveredPage(reference("example:removed_symbol"));
+        NotebookContents contents = new NotebookContents(List.of(first, ItemStack.EMPTY, unknown));
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), contents);
+
+        CompoundTag serialized = (CompoundTag)notebook.saveOptional(helper.getLevel().registryAccess());
+        ItemStack restored = ItemStack.parseOptional(helper.getLevel().registryAccess(), serialized);
+        NotebookContents restoredContents = restored.get(ModDataComponents.NOTEBOOK_CONTENTS.get());
+        helper.assertTrue(restoredContents != null, "Notebook contents must survive ItemStack persistence");
+        helper.assertValueEqual(restoredContents.pages().size(), 3,
+                "Notebook persistence must retain ordered positions");
+        helper.assertTrue(restoredContents.pages().get(1).isEmpty(),
+                "Notebook persistence must retain empty positions between pages");
+        helper.assertValueEqual(restoredContents.pages().get(0).getHoverName().getString(), "Foundation",
+                "Renamed contained pages must retain their names");
+        helper.assertValueEqual(PageItem.content(restoredContents.pages().get(2)).kind(),
+                PageContent.Kind.UNRESOLVED_SYMBOL,
+                "Unknown symbol pages must remain present and removable");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void notebookMenuValidatesInsertionAndPersistsReorder(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        player.setItemInHand(InteractionHand.MAIN_HAND, notebook);
+        NotebookMenu menu = new NotebookMenu(7, player.getInventory(), InteractionHand.MAIN_HAND);
+        ItemStack first = PageItem.createSymbolPage(reference("rivencraft:terrain/standard"));
+        first.set(net.minecraft.core.component.DataComponents.CUSTOM_NAME,
+                net.minecraft.network.chat.Component.literal("Terrain Base"));
+        ItemStack second = PageItem.createRecoveredPage(reference("example:removed_symbol"));
+
+        helper.assertFalse(menu.getSlot(0).mayPlace(new ItemStack(Items.DIRT)),
+                "Notebook slots must reject non-Page items");
+        menu.getSlot(0).set(first);
+        menu.getSlot(1).set(second);
+        helper.assertTrue(menu.clickMenuButton(player, NotebookMenu.MOVE_NEXT_BASE),
+                "The server menu must accept a valid adjacent reorder");
+
+        NotebookContents saved = notebook.get(ModDataComponents.NOTEBOOK_CONTENTS.get());
+        helper.assertTrue(saved != null, "Menu changes must persist immediately to the Notebook item");
+        helper.assertValueEqual(saved.pages().get(1).getHoverName().getString(), "Terrain Base",
+                "Reordering must preserve existing Page item data");
+        helper.assertValueEqual(PageItem.content(saved.pages().get(0)).kind(),
+                PageContent.Kind.UNRESOLVED_SYMBOL,
+                "Reordering must preserve unresolved pages");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void notebookMenuSurvivesInventoryStackReplacementAndClicks(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        player.setItemInHand(InteractionHand.MAIN_HAND, new ItemStack(ModItems.NOTEBOOK.get()));
+        NotebookMenu menu = new NotebookMenu(8, player.getInventory(), InteractionHand.MAIN_HAND);
+
+        // Slot synchronization may replace the ItemStack object while the Notebook remains held.
+        player.setItemInHand(InteractionHand.MAIN_HAND, player.getMainHandItem().copy());
+        helper.assertTrue(menu.stillValid(player),
+                "Replacing the held stack object must not close an open Notebook menu");
+        menu.getSlot(0).set(PageItem.createSymbolPage(reference("rivencraft:terrain/standard")));
+        helper.assertTrue(player.getMainHandItem().has(ModDataComponents.NOTEBOOK_CONTENTS.get()),
+                "Page edits must persist to the current held Notebook stack");
+
+        player.getInventory().setItem(9, new ItemStack(Items.DIRT));
+        menu.clicked(NotebookMenu.NOTEBOOK_SLOTS, 0, ClickType.PICKUP, player);
+        helper.assertTrue(menu.getCarried().is(Items.DIRT),
+                "Clicking a player inventory item must pick it up without closing the Notebook");
+        helper.assertTrue(menu.stillValid(player),
+                "Normal inventory clicks must leave the Notebook menu valid");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void notebookMenuPreservesSparsePagePositions(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        player.setItemInHand(InteractionHand.MAIN_HAND, new ItemStack(ModItems.NOTEBOOK.get()));
+        NotebookMenu menu = new NotebookMenu(9, player.getInventory(), InteractionHand.MAIN_HAND);
+        ItemStack page = PageItem.createSymbolPage(reference("rivencraft:terrain/standard"));
+        menu.setCarried(page);
+
+        menu.clicked(9, 0, ClickType.PICKUP, player);
+        helper.assertTrue(menu.getCarried().isEmpty(),
+                "Clicking a distant empty Notebook slot must place the carried Page");
+        NotebookContents saved = player.getMainHandItem().get(ModDataComponents.NOTEBOOK_CONTENTS.get());
+        helper.assertTrue(saved != null && saved.pages().size() > 9,
+                "Notebook persistence must extend through the highest occupied position");
+        for (int index = 0; index < 9; index++) {
+            helper.assertTrue(saved.pages().get(index).isEmpty(),
+                    "Earlier empty page positions must remain empty rather than being packed together");
+        }
+        helper.assertValueEqual(PageItem.content(saved.pages().get(9)).kind(), PageContent.Kind.SYMBOL,
+                "The Page must remain in the selected distant position");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void inkVialsPersistAndOnlyStackWithMatchingContents(GameTestHelper helper) {
+        ItemStack vial = new ItemStack(ModItems.INK_VIAL.get());
+        vial.set(ModDataComponents.INK_REMAINING.get(), 7);
+        CompoundTag serialized = (CompoundTag) vial.saveOptional(helper.getLevel().registryAccess());
+        ItemStack restored = ItemStack.parseOptional(helper.getLevel().registryAccess(), serialized);
+        helper.assertValueEqual(InkVialItem.remaining(restored), 7,
+                "Remaining ink must survive ItemStack persistence");
+        helper.assertTrue(ItemStack.isSameItemSameComponents(vial, restored),
+                "Vials with equal ink contents must be eligible to stack");
+        helper.assertFalse(ItemStack.isSameItemSameComponents(vial, new ItemStack(ModItems.INK_VIAL.get())),
+                "Vials with different ink contents must not stack");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void linkPanelPreparationConsumesOnePageAndConfiguredInkOnlyOnSuccess(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        ItemStack pages = new ItemStack(Items.PAPER, 2);
+        ItemStack vial = new ItemStack(ModItems.INK_VIAL.get());
+        player.setItemInHand(InteractionHand.MAIN_HAND, vial);
+        player.setItemInHand(InteractionHand.OFF_HAND, pages);
+
+        helper.assertTrue(WritingInkService.prepareLinkPanel(player, InteractionHand.MAIN_HAND),
+                "Paper and sufficient ink must prepare one link panel");
+        helper.assertValueEqual(pages.getCount(), 1, "Preparation must consume exactly one paper");
+        helper.assertValueEqual(InkVialItem.remaining(player.getMainHandItem()),
+                InkVialItem.CAPACITY - WritingInkService.linkPanelCost(),
+                "Preparation must consume exactly the server-configured ink cost");
+        long panels = player.getInventory().items.stream()
+                .filter(stack -> stack.is(ModItems.PAGE.get())
+                        && PageItem.content(stack).kind() == PageContent.Kind.LINK_PANEL)
+                .mapToInt(ItemStack::getCount).sum();
+        helper.assertValueEqual(panels, 1L, "Preparation must output exactly one link panel");
+
+        ItemStack written = PageItem.createSymbolPage(reference("rivencraft:terrain/standard"));
+        player.setItemInHand(InteractionHand.OFF_HAND, written);
+        int inkBefore = InkVialItem.remaining(player.getMainHandItem());
+        helper.assertFalse(WritingInkService.prepareLinkPanel(player, InteractionHand.MAIN_HAND),
+                "A written Page must not be overwritten as a link panel");
+        helper.assertValueEqual(InkVialItem.remaining(player.getMainHandItem()), inkBefore,
+                "Rejected writing must not consume ink");
+        helper.assertValueEqual(PageItem.content(written).kind(), PageContent.Kind.SYMBOL,
+                "Rejected writing must not modify the input Page");
+
+        ItemStack lowInk = new ItemStack(ModItems.INK_VIAL.get());
+        lowInk.set(ModDataComponents.INK_REMAINING.get(), WritingInkService.linkPanelCost() - 1);
+        player.setItemInHand(InteractionHand.MAIN_HAND, lowInk);
+        player.setItemInHand(InteractionHand.OFF_HAND, new ItemStack(Items.PAPER));
+        helper.assertFalse(WritingInkService.prepareLinkPanel(player, InteractionHand.MAIN_HAND),
+                "Insufficient ink must reject link-panel preparation");
+        helper.assertValueEqual(InkVialItem.remaining(player.getMainHandItem()),
+                WritingInkService.linkPanelCost() - 1,
+                "Insufficient ink must remain untouched");
+        helper.assertTrue(player.getOffhandItem().is(Items.PAPER),
+                "Insufficient ink must leave paper untouched");
+
+        lowInk.set(ModDataComponents.INK_REMAINING.get(), WritingInkService.linkPanelCost());
+        helper.assertTrue(WritingInkService.prepareLinkPanel(player, InteractionHand.MAIN_HAND),
+                "Exact remaining ink must be usable");
+        helper.assertTrue(player.getMainHandItem().is(Items.GLASS_BOTTLE),
+                "A depleted Ink Vial must return a reusable glass bottle");
+        helper.assertValueEqual(PageItem.content(player.getOffhandItem()).kind(),
+                PageContent.Kind.LINK_PANEL,
+                "A single paper must be replaced by one Link Panel Page");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void stackedInkVialsSplitWithoutChangingTheOtherVials(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        player.setItemInHand(InteractionHand.MAIN_HAND, new ItemStack(ModItems.INK_VIAL.get(), 2));
+        player.setItemInHand(InteractionHand.OFF_HAND, new ItemStack(Items.PAPER));
+
+        helper.assertTrue(WritingInkService.prepareLinkPanel(player, InteractionHand.MAIN_HAND),
+                "A stack of full vials must support preparing one panel");
+        helper.assertValueEqual(player.getMainHandItem().getCount(), 1,
+                "Using one vial must leave the other full vial in hand");
+        helper.assertValueEqual(InkVialItem.remaining(player.getMainHandItem()), InkVialItem.CAPACITY,
+                "The unconsumed vial must remain full");
+        long partialVials = player.getInventory().items.stream()
+                .filter(stack -> stack.is(ModItems.INK_VIAL.get())
+                        && InkVialItem.remaining(stack) == InkVialItem.CAPACITY - WritingInkService.linkPanelCost())
+                .mapToInt(ItemStack::getCount).sum();
+        helper.assertValueEqual(partialVials, 1L,
+                "The used vial must reappear with only its own ink reduced");
+        helper.succeed();
+    }
+
+    private static SymbolReference reference(String id) {
+        return new SymbolReference(ResourceLocation.parse(id));
+    }
+}

src/main/java/net/dnorberg/rivencraft/gametest/WritingDeskGameTests.java

@@ -0,0 +1,622 @@
+package net.dnorberg.rivencraft.gametest;
+
+import java.util.List;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.block.WritingDeskBlock;
+import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModBlocks;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.world.entity.item.ItemEntity;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.phys.AABB;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class WritingDeskGameTests {
+    private WritingDeskGameTests() {}
+
+    @GameTest(template = "empty")
+    public static void inventoryAndActiveCollectionPersist(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var original = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        original.setItem(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        original.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        original.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 12));
+        original.setActiveCollection(2);
+        var saved = original.saveWithoutMetadata(helper.getLevel().registryAccess());
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(saved, helper.getLevel().registryAccess());
+        helper.assertTrue(restored.getItem(0).is(ModItems.NOTEBOOK.get()), "Notebook lost on save/load");
+        helper.assertTrue(restored.getItem(WritingDeskBlockEntity.INK).is(ModItems.INK_VIAL.get()), "Ink lost on save/load");
+        helper.assertValueEqual(restored.getItem(WritingDeskBlockEntity.PAPER).getCount(), 12, "Pages lost on save/load");
+        helper.assertValueEqual(restored.activeCollection(), 2, "Active collection lost on save/load");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void breakingDeskDropsItsStoredItemsOnce(GameTestHelper helper) {
+        BlockPos relative = new BlockPos(1, 1, 1);
+        BlockPos pos = helper.absolutePos(relative);
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 12));
+        helper.getLevel().setBlock(pos, Blocks.AIR.defaultBlockState(), 3);
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(2));
+        int notebooks = drops.stream().filter(e -> e.getItem().is(ModItems.NOTEBOOK.get())).mapToInt(e -> e.getItem().getCount()).sum();
+        int bottles = drops.stream().filter(e -> e.getItem().is(Items.GLASS_BOTTLE)).mapToInt(e -> e.getItem().getCount()).sum();
+        int pages = drops.stream().filter(e -> e.getItem().is(Items.PAPER)).mapToInt(e -> e.getItem().getCount()).sum();
+        helper.assertValueEqual(notebooks, 1, "Notebook must drop exactly once");
+        helper.assertValueEqual(bottles, 1, "Consumed vial must return one glass bottle on break");
+        helper.assertValueEqual(pages, 12, "Pages must drop without loss");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void menuTransfersWithoutDuplicationAndClosesWhenReplaced(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        player.getInventory().setItem(9, new ItemStack(Items.PAPER, 12));
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertTrue(menu.stillValid(player), "Placed desk must keep its menu valid");
+        helper.assertTrue(menu.clickMenuButton(player, 3), "Active collection control must accept a valid tab");
+        helper.assertValueEqual(desk.activeCollection(), 3, "Selected tab must be stored on the desk");
+        menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT + 1);
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 12, "Shift-click must deposit all pages");
+        helper.assertTrue(player.getInventory().getItem(9).isEmpty(), "Shift-click must consume player source stack");
+        menu.quickMoveStack(player, WritingDeskBlockEntity.PAPER);
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.PAPER).isEmpty(), "Shift-click must empty desk source slot");
+        int total = player.getInventory().items.stream().filter(stack -> stack.is(Items.PAPER))
+                .mapToInt(ItemStack::getCount).sum();
+        helper.assertValueEqual(total, 12, "Round-trip must not lose or duplicate pages");
+        helper.getLevel().setBlock(pos, Blocks.AIR.defaultBlockState(), 3);
+        helper.assertFalse(menu.stillValid(player), "Removed desk must invalidate menu");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void takingCopySpendsPaperAndOneInkThenReturnsGlassBottle(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack source = PageItem.createLinkPanelPage();
+        desk.setItem(0, source.copy());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 2));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        menu.broadcastChanges();
+        helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().is(ModItems.PAGE.get()),
+                "A source page with paper and ink must preview one copy");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 2,
+                "Previewing must not consume paper");
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Inserting a vial must fill the empty bar before copying");
+        menu.clicked(WritingDeskMenu.COPY_RESULT, 0, ClickType.PICKUP, player);
+        helper.assertTrue(menu.getCarried().is(ModItems.PAGE.get()), "Taking result must give the copied page");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 1,
+                "Taking a copy must consume one paper");
+        helper.assertValueEqual(desk.inkRemaining(), 15, "First copy must consume one ink");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(), "Refill must consume one vial");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.RETURN).is(Items.GLASS_BOTTLE),
+                "Refill must return a vanilla glass bottle");
+        helper.assertTrue(desk.getItem(0).is(ModItems.PAGE.get()), "Source page must remain untouched");
+        helper.assertTrue(menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT).is(ModItems.PAGE.get()),
+                "A second copy must remain available from the same ink fill");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.PAPER).isEmpty(),
+                "Two copies must consume exactly two paper");
+        helper.assertValueEqual(desk.inkRemaining(), 14, "Two copies must spend exactly two of sixteen ink");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 1,
+                "A second copy must not consume another vial");
+        var saved = desk.saveWithoutMetadata(helper.getLevel().registryAccess());
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(saved, helper.getLevel().registryAccess());
+        helper.assertValueEqual(restored.inkRemaining(), 14, "Ink meter must persist across saves");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void emptyDeskInkBarRefillsWithoutCopying(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get(), 2));
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Inserting a vial must refill immediately");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.INK).getCount(), 1,
+                "Refill must consume exactly one vial");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.RETURN).is(Items.GLASS_BOTTLE),
+                "Refill must put a vanilla glass bottle in the return slot");
+        helper.runAfterDelay(2, () -> {
+            helper.assertValueEqual(desk.inkRemaining(), 16, "Full bar must not refill again");
+            helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.INK).getCount(), 1,
+                    "Full bar must leave the second vial untouched");
+            helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 1,
+                    "Full bar must not create another bottle");
+            helper.succeed();
+        });
+    }
+
+    @GameTest(template = "empty")
+    public static void emptyDeskInkBarWaitsForBottleSpace(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(WritingDeskBlockEntity.RETURN, new ItemStack(Items.GLASS_BOTTLE, 64));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        helper.assertValueEqual(desk.inkRemaining(), 0, "Full bottle slot must block automatic refill");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).is(ModItems.INK_VIAL.get()),
+                "Blocked refill must preserve the vial");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 64,
+                "Blocked refill must preserve the bottle stack");
+        desk.removeItem(WritingDeskBlockEntity.RETURN, 1);
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Removing a bottle must immediately permit refill");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(),
+                "Refill must consume the waiting vial");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 64,
+                "Refill must return one glass bottle to the available space");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void shiftClickCopiesOnlyWhenResourcesAndBottleSpaceExist(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(0, PageItem.createLinkPanelPage());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 2));
+        desk.setItem(WritingDeskBlockEntity.RETURN, new ItemStack(Items.GLASS_BOTTLE, 64));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertTrue(menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT).isEmpty(),
+                "Full bottle return must block refill without consuming supplies");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 2,
+                "Blocked copy must leave paper untouched");
+        desk.removeItem(WritingDeskBlockEntity.RETURN, 1);
+        ItemStack copied = menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT);
+        helper.assertTrue(copied.is(ModItems.PAGE.get()), "Shift-click must transfer one copy");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 1,
+                "Shift-click must consume one paper");
+        helper.assertValueEqual(desk.inkRemaining(), 15, "Shift-click must consume one ink");
+        int copies = player.getInventory().items.stream().filter(stack -> stack.is(ModItems.PAGE.get()))
+                .mapToInt(ItemStack::getCount).sum();
+        helper.assertValueEqual(copies, 1, "Shift-click must give exactly one page");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void selectedNotebookPageControlsCopyPreview(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(),
+                new NotebookContents(List.of(ItemStack.EMPTY, PageItem.createLinkPanelPage())));
+        desk.setItem(0, notebook);
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        menu.broadcastChanges();
+        helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().isEmpty(),
+                "An empty selected position must not create a copy");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.PAGE_BUTTON_BASE + 1), "Second page selection must be accepted");
+        menu.broadcastChanges();
+        helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().is(ModItems.PAGE.get()),
+                "Selecting the populated page must show a copy");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void twoViewersCannotTakeTheSameLastSheet(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(0, PageItem.createLinkPanelPage());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var first = helper.makeMockServerPlayerInLevel();
+        var second = helper.makeMockServerPlayerInLevel();
+        first.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        second.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu firstMenu = new WritingDeskMenu(1, first.getInventory(), desk);
+        WritingDeskMenu secondMenu = new WritingDeskMenu(2, second.getInventory(), desk);
+        firstMenu.broadcastChanges();
+        secondMenu.broadcastChanges();
+        helper.assertTrue(firstMenu.quickMoveStack(first, WritingDeskMenu.COPY_RESULT).is(ModItems.PAGE.get()),
+                "First viewer should take the last available copy");
+        helper.assertTrue(secondMenu.quickMoveStack(second, WritingDeskMenu.COPY_RESULT).isEmpty(),
+                "Second viewer must not copy the already-consumed paper");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.PAPER).isEmpty(),
+                "Shared desk must spend paper only once");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void catalogAggregatesKnownSymbolsAcrossCollections(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ResourceLocation known = ResourceLocation.parse("rivencraft:terrain/standard");
+        ItemStack page = PageItem.createSymbolPage(new SymbolReference(known));
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(List.of(page.copy())));
+        desk.setItem(0, page);
+        desk.setItem(1, notebook);
+        helper.assertValueEqual(WritingDeskCatalog.available(desk).size(), 1,
+                "Duplicate symbols across loose pages and notebooks must appear once");
+        helper.assertValueEqual(WritingDeskCatalog.available(desk).getFirst().id(), known,
+                "Catalog must retain the authoritative symbol ID");
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.CATALOG_BUTTON_BASE + 1), "Out-of-range catalog index must be rejected");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.CATALOG_BUTTON_BASE), "Known catalog symbol must be selectable");
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        menu.broadcastChanges();
+        helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().is(ModItems.PAGE.get()),
+                "Catalog selection must preview a copy of the known symbol");
+        desk.setItem(0, ItemStack.EMPTY);
+        desk.setItem(1, ItemStack.EMPTY);
+        menu.broadcastChanges();
+        helper.assertTrue(menu.catalog().isEmpty(), "Removed sources must invalidate catalog for the viewer");
+        helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().isEmpty(),
+                "Removed sources must invalidate the copy output");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void fullInventoryCannotConsumeCopyMaterials(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(0, PageItem.createLinkPanelPage());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        for (int i = 0; i < 36; i++) player.getInventory().setItem(i, new ItemStack(Items.COBBLESTONE, 64));
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertTrue(menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT).isEmpty(),
+                "Full inventory must reject shift-click copy");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 1,
+                "Rejected copy must preserve paper");
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Rejected copy must preserve the filled ink meter");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(),
+                "The vial should already have refilled the empty meter");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void twoBlockDeskSharesOneInventoryAndBreaksTogether(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var block = ModBlocks.WRITING_DESK.get();
+        var state = block.defaultBlockState().setValue(WritingDeskBlock.FACING, Direction.NORTH);
+        helper.getLevel().setBlock(pos, state, 3);
+        block.setPlacedBy(helper.getLevel(), pos, state, null, new ItemStack(block));
+        BlockPos extension = pos.relative(Direction.EAST);
+        helper.assertTrue(helper.getLevel().getBlockState(extension).is(block),
+                "Placing a desk must reserve the adjacent second block");
+        helper.assertTrue(helper.getLevel().getBlockState(extension).getValue(WritingDeskBlock.EXTENSION),
+                "Adjacent half must be marked as an extension");
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        helper.assertTrue(helper.getLevel().getBlockEntity(extension) == null,
+                "Extension must not duplicate the inventory");
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 7));
+        helper.getLevel().destroyBlock(extension, true);
+        helper.assertTrue(helper.getLevel().getBlockState(pos).isAir(),
+                "Breaking the extension must remove the controller");
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(3));
+        int desks = drops.stream().filter(e -> e.getItem().is(block.asItem()))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        int paper = drops.stream().filter(e -> e.getItem().is(Items.PAPER))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        helper.assertValueEqual(desks, 1, "Breaking either half must drop one desk");
+        helper.assertValueEqual(paper, 7, "Breaking either half must drop stored paper once");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void breakingControllerRemovesExtensionWithoutDuplicateDesk(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var block = ModBlocks.WRITING_DESK.get();
+        var state = block.defaultBlockState().setValue(WritingDeskBlock.FACING, Direction.NORTH);
+        helper.getLevel().setBlock(pos, state, 3);
+        block.setPlacedBy(helper.getLevel(), pos, state, null, new ItemStack(block));
+        BlockPos extension = pos.relative(Direction.EAST);
+        helper.getLevel().destroyBlock(pos, true);
+        helper.assertTrue(helper.getLevel().getBlockState(extension).isAir(),
+                "Breaking the controller must remove the extension");
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(3));
+        int desks = drops.stream().filter(e -> e.getItem().is(block.asItem()))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        helper.assertValueEqual(desks, 1, "Controller break must drop exactly one desk");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void openDeskDoesNotOccludeTerrain(GameTestHelper helper) {
+        helper.assertFalse(ModBlocks.WRITING_DESK.get().defaultBlockState().canOcclude(),
+                "Open shelves must not cull terrain behind the desk");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void allPagesSelectionUsesTheRequestedPhysicalTab(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack first = PageItem.createLinkPanelPage();
+        ItemStack second = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        desk.setItem(0, first);
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(),
+                new NotebookContents(List.of(ItemStack.EMPTY, second)));
+        desk.setItem(1, notebook);
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + 2 * NotebookContents.MAX_PAGES),
+                "ALL view must reject empty cross-tab positions");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + NotebookContents.MAX_PAGES + 1),
+                "ALL view must accept the populated second tab page");
+        helper.assertTrue(ItemStack.matches(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem(), second),
+                "Copy preview must match the physical page selected from the other tab");
+        helper.assertValueEqual(desk.activeCollection(), 0,
+                "Selecting from ALL must not silently change the active tab");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void tabGroupsCycleByFourAndProtectHiddenSlots(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        var otherViewer = new WritingDeskMenu(2, player.getInventory(), desk);
+        menu.clickMenuButton(player, WritingDeskMenu.PREVIOUS_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 0, "Previous must stop at tabs 1-4");
+        menu.clickMenuButton(player, WritingDeskMenu.NEXT_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 4, "Next must show tabs 5-8");
+        helper.assertValueEqual(otherViewer.firstVisibleTab(), 0, "Cycling must not move another viewer's slots");
+        helper.assertFalse(menu.getSlot(0).isActive(), "Earlier tab slots must be hidden");
+        helper.assertTrue(menu.getSlot(4).isActive(), "New group's slots must be interactive");
+        desk.setItem(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        menu.clicked(0, 0, ClickType.PICKUP, player);
+        helper.assertTrue(menu.getCarried().isEmpty(), "Hidden slot clicks must not take items");
+        helper.assertTrue(menu.quickMoveStack(player, 0).isEmpty(), "Hidden shift-click must be rejected");
+        player.getInventory().setItem(9, new ItemStack(ModItems.NOTEBOOK.get()));
+        menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT + 1);
+        helper.assertTrue(desk.getItem(4).is(ModItems.NOTEBOOK.get()), "Shift-click must use the visible group");
+        for (int i = 0; i < 30; i++) menu.clickMenuButton(player, WritingDeskMenu.NEXT_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 84, "Last group must be tabs 85-88");
+        helper.assertTrue(menu.clickMenuButton(player, 87), "Tab 88 must be selectable without page-ID collisions");
+        helper.assertValueEqual(desk.activeCollection(), 87, "Tab 88 must become active");
+        helper.assertFalse(menu.clickMenuButton(player, 88), "Tab 89 must not exist");
+        desk.setItem(87, PageItem.createLinkPanelPage());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + 87 * NotebookContents.MAX_PAGES),
+                "ALL must select a physical page from tab 88");
+        helper.assertTrue(menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT).is(ModItems.PAGE.get()),
+                "Tab 88's page must be copyable");
+        menu.clickMenuButton(player, WritingDeskMenu.PREVIOUS_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 80, "Previous must move back four tabs");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void oldDeskInventoryMigratesAndAll88TabsPersist(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var registries = helper.getLevel().registryAccess();
+        var oldItems = net.minecraft.core.NonNullList.withSize(8, ItemStack.EMPTY);
+        oldItems.set(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        oldItems.set(3, PageItem.createLinkPanelPage());
+        oldItems.set(4, new ItemStack(ModItems.INK_VIAL.get(), 2));
+        oldItems.set(5, new ItemStack(Items.GLASS_BOTTLE, 3));
+        oldItems.set(6, new ItemStack(Items.PAPER, 12));
+        oldItems.set(7, PageItem.createLinkPanelPage());
+        var oldTag = new net.minecraft.nbt.CompoundTag();
+        net.minecraft.world.ContainerHelper.saveAllItems(oldTag, oldItems, registries);
+        oldTag.putInt("InkRemaining", 7);
+        oldTag.putInt("ActiveCollection", 3);
+        var desk = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        desk.loadWithComponents(oldTag, registries);
+        for (int i = 0; i < 4; i++) {
+            helper.assertTrue(ItemStack.matches(desk.getItem(i), oldItems.get(i)), "Original tab must survive migration");
+            helper.assertTrue(ItemStack.matches(desk.getItem(WritingDeskBlockEntity.INK + i), oldItems.get(4 + i)),
+                    "Original supplies and legacy output must survive migration");
+            helper.assertTrue(desk.getItem(4 + i).isEmpty(), "Supplies must not be duplicated into new tabs");
+        }
+        helper.assertValueEqual(desk.inkRemaining(), 7, "Migration must preserve ink meter");
+        helper.assertValueEqual(desk.activeCollection(), 3, "Migration must preserve active tab");
+        for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++) desk.setItem(i, PageItem.createLinkPanelPage());
+        desk.setActiveCollection(87);
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(desk.saveWithoutMetadata(registries), registries);
+        for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++)
+            helper.assertTrue(restored.getItem(i).is(ModItems.PAGE.get()), "All 88 tab contents must survive save/load");
+        helper.assertValueEqual(restored.activeCollection(), 87, "Tab 88 selection must survive save/load");
+        helper.assertValueEqual(restored.getItem(WritingDeskBlockEntity.PAPER).getCount(), 12, "Reload must not repeat migration");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void surfacePlacesCarriedPagesWithoutLossOrOverwrite(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(87, new ItemStack(ModItems.NOTEBOOK.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        ItemStack held = PageItem.createLinkPanelPage().copyWithCount(3);
+        ItemStack expectedPage = held.copyWithCount(1);
+        player.getInventory().setItem(9, held);
+        menu.clicked(WritingDeskMenu.COPY_RESULT + 1, 0, ClickType.PICKUP, player);
+        int lastPosition = WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 87 * NotebookContents.MAX_PAGES + 26;
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition), "Surface must place into final notebook position");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Placing must consume exactly one held page");
+        var pages = desk.getItem(87).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertValueEqual(pages.size(), 27, "Placement must preserve addressed position");
+        helper.assertTrue(pages.get(0).isEmpty() && pages.get(25).isEmpty(), "Placement must preserve preceding gaps");
+        helper.assertTrue(ItemStack.matches(pages.get(26), expectedPage), "Stored page must preserve components");
+        helper.assertFalse(menu.clickMenuButton(player, lastPosition), "Occupied position must not be overwritten");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Rejected placement must preserve cursor");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 88 * NotebookContents.MAX_PAGES),
+                "Out-of-range placement must be rejected");
+        helper.assertValueEqual(menu.pageCapacity(87), NotebookContents.MAX_PAGES, "Notebook tab must expose normal notebook capacity");
+        helper.assertValueEqual(menu.pageCapacity(0), 0, "Empty tab has no page storage");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE), "Empty tab must require a collection first");
+        desk.setItem(0, PageItem.createLinkPanelPage());
+        helper.assertValueEqual(menu.pageCapacity(0), 1, "Loose page tab must expose exactly one position");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE), "Loose page must not be replaced");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 1), "Loose page tab must not grow extra positions");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Rejected placements must preserve cursor");
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition - 1), "A second empty notebook position must accept a page");
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition - 2), "A third empty notebook position must accept the last page");
+        helper.assertTrue(menu.getCarried().isEmpty(), "Final placement must clear cursor");
+        menu.setCarried(new ItemStack(Items.DIAMOND));
+        helper.assertFalse(menu.clickMenuButton(player, lastPosition - 3), "Non-page items must be rejected");
+        helper.assertTrue(menu.getCarried().is(Items.DIAMOND), "Rejected item must remain held");
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(desk.saveWithoutMetadata(helper.getLevel().registryAccess()), helper.getLevel().registryAccess());
+        helper.assertValueEqual(restored.getItem(87).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 3,
+                "Placed pages must persist in the notebook");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void deskSurfaceDragMovesAndSwapsNotebookPages(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack linkPanel = PageItem.createLinkPanelPage();
+        ItemStack terrain = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        ItemStack firstBook = new ItemStack(ModItems.NOTEBOOK.get());
+        firstBook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(List.of(linkPanel, terrain)));
+        desk.setItem(0, firstBook);
+        desk.setItem(1, new ItemStack(ModItems.NOTEBOOK.get()));
+        desk.setItem(2, PageItem.createLinkPanelPage());
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        int moveToEmpty = WritingDeskMenu.movePageButtonId(0, 0, 0, 26);
+        helper.assertTrue(menu.clickMenuButton(player, moveToEmpty), "Drag must move to a distant empty notebook position");
+        var pages = desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(pages.get(0).isEmpty(), "Moving must clear the source position");
+        helper.assertTrue(ItemStack.matches(pages.get(26), linkPanel), "Moving must preserve page components");
+        helper.assertValueEqual(desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 2,
+                "Moving must preserve total page count");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 26, 0, 1)),
+                "Drag onto an occupied position must swap pages");
+        pages = desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(pages.get(1), linkPanel) && ItemStack.matches(pages.get(26), terrain),
+                "Swap must preserve both pages");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 1, 1, 5)),
+                "Drag into another notebook must work");
+        var otherPages = desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(otherPages.get(5), linkPanel)
+                && desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(1).isEmpty(),
+                "Cross notebook move must have one destination and no old source");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 1, 1, 6)),
+                "Dragging an empty source must be rejected");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(2, 0, 1, 6)),
+                "A loose page should move into a notebook position");
+        helper.assertTrue(desk.getItem(2).isEmpty()
+                && desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(6).is(ModItems.PAGE.get()),
+                "Moving a loose page must empty its tab without losing the item");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(1, 5, 1, 5)),
+                "A no-op drag must be rejected");
+        menu.setCarried(new ItemStack(Items.DIAMOND));
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(1, 5, 1, 6)),
+                "Held inventory items must not be moved by a panel drag");
+        helper.assertTrue(ItemStack.matches(desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(5), linkPanel),
+                "Rejected drags must leave notebook data intact");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void deskSurfaceDragExtractsPagesToInventoryAndTabs(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack page = PageItem.createLinkPanelPage();
+        ItemStack source = new ItemStack(ModItems.NOTEBOOK.get());
+        source.set(ModDataComponents.NOTEBOOK_CONTENTS.get(),
+                new NotebookContents(List.of(page, page, page, page, page, page)));
+        desk.setItem(0, source);
+        ItemStack otherBook = new ItemStack(ModItems.NOTEBOOK.get());
+        ItemStack terrain = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        otherBook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(List.of(terrain)));
+        desk.setItem(2, otherBook);
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        player.getInventory().setItem(10, page.copyWithCount(2));
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        int inventoryStart = WritingDeskMenu.COPY_RESULT + 1;
+
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 0, -1)),
+                "Dropping away from a slot must return the page to the cursor");
+        helper.assertTrue(ItemStack.matches(menu.getCarried(), page), "Cursor must hold the original page item");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 1, inventoryStart)),
+                "Extraction must not replace an occupied cursor");
+        menu.setCarried(ItemStack.EMPTY);
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 1, inventoryStart)),
+                "Dropping on player inventory must transfer a page");
+        helper.assertTrue(ItemStack.matches(player.getInventory().getItem(9), page),
+                "Transferred page must retain its components");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 2, 1)),
+                "Dropping on an empty tab must store a loose page");
+        helper.assertTrue(ItemStack.matches(desk.getItem(1), page), "Tab must hold the extracted page");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 3, 2)),
+                "Dropping on a notebook tab must insert the page");
+        var otherPages = desk.getItem(2).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(otherPages.get(0), terrain)
+                && ItemStack.matches(otherPages.get(1), page), "Notebook drop must preserve existing pages");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 4, inventoryStart + 1)),
+                "Dropping on a matching inventory stack must merge one page");
+        helper.assertValueEqual(player.getInventory().getItem(10).getCount(), 3, "Merge must add exactly one page");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 5, 1)),
+                "Occupied loose-page tabs must reject a drop");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 5, WritingDeskBlockEntity.INK)),
+                "Ink slot must not accept an extracted page");
+        helper.assertValueEqual(desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 1,
+                "Rejected drops must leave the remaining source page in the notebook");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(1, 0, -1)),
+                "A loose page shown on the panel must be draggable back to the cursor");
+        helper.assertTrue(desk.getItem(1).isEmpty() && ItemStack.matches(menu.getCarried(), page),
+                "Extracting a loose page must empty its tab and return the same item");
+        helper.succeed();
+    }
+}

src/main/java/net/dnorberg/rivencraft/item/InkVialItem.java

@@ -0,0 +1,47 @@
+package net.dnorberg.rivencraft.item;
+
+import java.util.List;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.writing.WritingInkService;
+import net.minecraft.ChatFormatting;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.InteractionResultHolder;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.TooltipFlag;
+import net.minecraft.world.level.Level;
+
+/** A stackable vial; the ink component is per vial, not shared across a stack. */
+public final class InkVialItem extends Item {
+    public static final int CAPACITY = 16;
+
+    public InkVialItem(Properties properties) {
+        super(properties);
+    }
+
+    public static int remaining(ItemStack vial) {
+        return vial.getOrDefault(ModDataComponents.INK_REMAINING.get(), CAPACITY);
+    }
+
+    @Override
+    public InteractionResultHolder<ItemStack> use(Level level, Player player, InteractionHand hand) {
+        if (!WritingInkService.canPrepareLinkPanel(player, hand)) {
+            return InteractionResultHolder.pass(player.getItemInHand(hand));
+        }
+        if (!level.isClientSide) {
+            WritingInkService.prepareLinkPanel(player, hand);
+        }
+        return InteractionResultHolder.sidedSuccess(player.getItemInHand(hand), level.isClientSide);
+    }
+
+    @Override
+    public void appendHoverText(ItemStack stack, TooltipContext context,
+                                List<Component> tooltip, TooltipFlag flag) {
+        tooltip.add(Component.translatable("item.rivencraft.ink_vial.remaining",
+                remaining(stack), CAPACITY).withStyle(ChatFormatting.GRAY));
+        tooltip.add(Component.translatable("item.rivencraft.ink_vial.usage")
+                .withStyle(ChatFormatting.GRAY));
+    }
+}

src/main/java/net/dnorberg/rivencraft/item/NotebookItem.java

@@ -0,0 +1,48 @@
+package net.dnorberg.rivencraft.item;
+
+import java.util.List;
+import net.dnorberg.rivencraft.menu.NotebookMenu;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.minecraft.ChatFormatting;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.InteractionResultHolder;
+import net.minecraft.world.SimpleMenuProvider;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.TooltipFlag;
+import net.minecraft.world.level.Level;
+
+public final class NotebookItem extends Item {
+    public NotebookItem(Properties properties) {
+        super(properties);
+    }
+
+    @Override
+    public InteractionResultHolder<ItemStack> use(Level level, Player player, InteractionHand hand) {
+        ItemStack notebook = player.getItemInHand(hand);
+        if (!level.isClientSide && player instanceof ServerPlayer serverPlayer) {
+            serverPlayer.openMenu(new SimpleMenuProvider(
+                    (containerId, inventory, ignored) -> new NotebookMenu(containerId, inventory, hand),
+                    notebook.getHoverName()),
+                    buffer -> buffer.writeBoolean(hand == InteractionHand.OFF_HAND));
+        }
+        return InteractionResultHolder.sidedSuccess(notebook, level.isClientSide);
+    }
+
+    @Override
+    public void appendHoverText(ItemStack stack, TooltipContext context,
+                                List<Component> tooltip, TooltipFlag flag) {
+        NotebookContents contents = stack.getOrDefault(
+                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY);
+        tooltip.add(Component.translatable("item.rivencraft.notebook.pages",
+                contents.pageCount(), NotebookContents.MAX_PAGES).withStyle(ChatFormatting.GRAY));
+        if (contents.unresolvedCount() > 0) {
+            tooltip.add(Component.translatable("item.rivencraft.notebook.unresolved",
+                    contents.unresolvedCount()).withStyle(ChatFormatting.RED));
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/item/PageItem.java

@@ -0,0 +1,135 @@
+package net.dnorberg.rivencraft.item;
+
+import java.util.List;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.minecraft.ChatFormatting;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.item.component.CustomModelData;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.TooltipFlag;
+
+/** One stackable Page item whose server-owned component identifies its writing state. */
+public final class PageItem extends Item {
+    public PageItem(Properties properties) {
+        super(properties);
+    }
+
+    public static ItemStack createSymbolPage(SymbolReference reference) {
+        if (!SymbolCatalog.isKnown(reference)) {
+            throw new IllegalArgumentException("Cannot create a page for unknown symbol " + reference.id());
+        }
+        return create(PageContent.symbol(reference));
+    }
+
+    public static ItemStack createLinkPanelPage() {
+        return create(PageContent.LINK_PANEL);
+    }
+
+    /** Restores saved unknown references without granting them validity for new writing operations. */
+    public static ItemStack createRecoveredPage(SymbolReference reference) {
+        return create(PageContent.unresolved(reference));
+    }
+
+    public static PageContent content(ItemStack stack) {
+        PageContent content = stack.get(ModDataComponents.PAGE_CONTENT.get());
+        return content == null ? PageContent.BLANK : content;
+    }
+
+    /** Server-side gate for Desk and Binder inputs; unresolved pages remain removable but not usable. */
+    public static boolean isUsableWriting(ItemStack stack) {
+        if (!stack.is(ModItems.PAGE.get())) {
+            return false;
+        }
+        PageContent resolved = content(stack).resolve();
+        return resolved.kind() == PageContent.Kind.BLANK
+                || resolved.kind() == PageContent.Kind.LINK_PANEL
+                || resolved.isResolvedSymbol();
+    }
+
+    @Override
+    public Component getName(ItemStack stack) {
+        Component customName = stack.get(DataComponents.CUSTOM_NAME);
+        if (customName != null) {
+            return customName;
+        }
+        PageContent content = content(stack);
+        return switch (content.kind()) {
+            case BLANK -> Component.translatable("item.rivencraft.page.blank");
+            case LINK_PANEL -> Component.translatable("item.rivencraft.page.link_panel");
+            case UNRESOLVED_SYMBOL -> Component.translatable("item.rivencraft.page.unresolved");
+            case SYMBOL -> symbolName(stack, content.symbol().orElseThrow());
+        };
+    }
+
+    @Override
+    public void appendHoverText(ItemStack stack, TooltipContext context,
+                                List<Component> tooltipComponents, TooltipFlag tooltipFlag) {
+        PageContent content = content(stack);
+        if (content.kind() == PageContent.Kind.BLANK) {
+            tooltipComponents.add(Component.translatable("item.rivencraft.page.blank.description")
+                    .withStyle(ChatFormatting.GRAY));
+            return;
+        }
+        if (content.kind() == PageContent.Kind.LINK_PANEL) {
+            tooltipComponents.add(Component.translatable("item.rivencraft.page.link_panel.description")
+                    .withStyle(ChatFormatting.GRAY));
+            return;
+        }
+        SymbolReference reference = content.symbol().orElseThrow();
+        SymbolDisplayMetadata metadata = content.kind() == PageContent.Kind.SYMBOL
+                ? stack.getOrDefault(ModDataComponents.PAGE_SYMBOL_DISPLAY.get(), SymbolCatalog.display(reference))
+                : SymbolDisplayMetadata.unresolved(reference);
+        if (metadata.resolved()) {
+            tooltipComponents.add(Component.translatable(metadata.descriptionTranslationKey())
+                    .withStyle(ChatFormatting.GRAY));
+        } else {
+            tooltipComponents.add(Component.translatable(
+                    "symbol.rivencraft.unresolved.description", reference.unresolvedName())
+                    .withStyle(ChatFormatting.RED));
+        }
+        tooltipComponents.add(Component.literal(reference.id().toString()).withStyle(ChatFormatting.DARK_GRAY));
+    }
+
+    private static ItemStack create(PageContent content) {
+        ItemStack stack = new ItemStack(ModItems.PAGE.get());
+        stack.set(ModDataComponents.PAGE_CONTENT.get(), content);
+        stack.set(DataComponents.CUSTOM_MODEL_DATA, new CustomModelData(modelIndex(content)));
+        if (content.kind() == PageContent.Kind.SYMBOL) {
+            stack.set(ModDataComponents.PAGE_SYMBOL_DISPLAY.get(),
+                    SymbolCatalog.display(content.symbol().orElseThrow()));
+        }
+        return stack;
+    }
+
+    private static Component symbolName(ItemStack stack, SymbolReference reference) {
+        SymbolDisplayMetadata metadata = stack.getOrDefault(
+                ModDataComponents.PAGE_SYMBOL_DISPLAY.get(), SymbolCatalog.display(reference));
+        return metadata.resolved()
+                ? Component.translatable(metadata.nameTranslationKey())
+                : Component.translatable("item.rivencraft.page.unresolved");
+    }
+
+    private static int modelIndex(PageContent content) {
+        return switch (content.kind()) {
+            case BLANK -> 0;
+            case LINK_PANEL -> 1;
+            case UNRESOLVED_SYMBOL -> 2;
+            case SYMBOL -> switch (content.symbol().orElseThrow().id().toString()) {
+                case "rivencraft:terrain/standard" -> 100;
+                case "rivencraft:biome/native" -> 101;
+                case "rivencraft:lighting/normal" -> 102;
+                case "rivencraft:weather/normal" -> 103;
+                case "rivencraft:celestial/normal_time" -> 104;
+                case "rivencraft:feature/caves" -> 105;
+                default -> 3;
+            };
+        };
+    }
+}

src/main/java/net/dnorberg/rivencraft/menu/NotebookMenu.java

@@ -0,0 +1,194 @@
+package net.dnorberg.rivencraft.menu;
+
+import java.util.List;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.registry.ModMenus;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.minecraft.core.NonNullList;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.world.Container;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.SimpleContainer;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+
+public final class NotebookMenu extends AbstractContainerMenu {
+    public static final int NOTEBOOK_SLOTS = NotebookContents.MAX_PAGES;
+    public static final int MOVE_PREVIOUS_BASE = 0;
+    public static final int MOVE_NEXT_BASE = NOTEBOOK_SLOTS;
+    private static final int PLAYER_INVENTORY_START = NOTEBOOK_SLOTS;
+    private final Inventory playerInventory;
+    private final InteractionHand hand;
+    private final int openedHotbarSlot;
+    private final NotebookContainer contents;
+
+    public NotebookMenu(int containerId, Inventory inventory, RegistryFriendlyByteBuf data) {
+        this(containerId, inventory, data.readBoolean() ? InteractionHand.OFF_HAND : InteractionHand.MAIN_HAND);
+    }
+
+    public NotebookMenu(int containerId, Inventory inventory, InteractionHand hand) {
+        super(ModMenus.NOTEBOOK.get(), containerId);
+        this.playerInventory = inventory;
+        this.hand = hand;
+        this.openedHotbarSlot = inventory.selected;
+        this.contents = new NotebookContainer(inventory, hand);
+
+        for (int row = 0; row < 3; row++) {
+            for (int column = 0; column < 9; column++) {
+                // The client draws these pages on a filtered, scrollable surface instead.
+                addSlot(new PageSlot(contents, column + row * 9, -1000, -1000));
+            }
+        }
+        for (int row = 0; row < 3; row++) {
+            for (int column = 0; column < 9; column++) {
+                int inventoryIndex = column + row * 9 + 9;
+                addSlot(playerSlot(inventoryIndex, 8 + column * 18, 135 + row * 18));
+            }
+        }
+        for (int column = 0; column < 9; column++) {
+            addSlot(playerSlot(column, 8 + column * 18, 193));
+        }
+    }
+
+    private Slot playerSlot(int inventoryIndex, int x, int y) {
+        boolean locked = hand == InteractionHand.MAIN_HAND && inventoryIndex == openedHotbarSlot;
+        return locked ? new LockedSlot(playerInventory, inventoryIndex, x, y)
+                : new Slot(playerInventory, inventoryIndex, x, y);
+    }
+
+    @Override
+    public boolean stillValid(Player player) {
+        return player.isAlive()
+                && (hand == InteractionHand.OFF_HAND || player.getInventory().selected == openedHotbarSlot)
+                && player.getItemInHand(hand).is(ModItems.NOTEBOOK.get());
+    }
+
+    @Override
+    public ItemStack quickMoveStack(Player player, int index) {
+        Slot slot = slots.get(index);
+        if (!slot.hasItem()) {
+            return ItemStack.EMPTY;
+        }
+        ItemStack source = slot.getItem();
+        ItemStack original = source.copy();
+        if (index < PLAYER_INVENTORY_START) {
+            if (!moveItemStackTo(source, PLAYER_INVENTORY_START, slots.size(), true)) {
+                return ItemStack.EMPTY;
+            }
+        } else {
+            if (!source.is(ModItems.PAGE.get())
+                    || !moveItemStackTo(source, 0, PLAYER_INVENTORY_START, false)) {
+                return ItemStack.EMPTY;
+            }
+        }
+        if (source.isEmpty()) {
+            slot.setByPlayer(ItemStack.EMPTY);
+        } else {
+            slot.setChanged();
+        }
+        return original;
+    }
+
+    @Override
+    public boolean clickMenuButton(Player player, int id) {
+        int source;
+        int target;
+        if (id >= MOVE_PREVIOUS_BASE && id < MOVE_NEXT_BASE) {
+            source = id;
+            target = source - 1;
+        } else if (id >= MOVE_NEXT_BASE && id < MOVE_NEXT_BASE + NOTEBOOK_SLOTS) {
+            source = id - MOVE_NEXT_BASE;
+            target = source + 1;
+        } else {
+            return false;
+        }
+        if (source < 0 || source >= NOTEBOOK_SLOTS || target < 0 || target >= NOTEBOOK_SLOTS
+                || contents.getItem(source).isEmpty()) {
+            return false;
+        }
+        contents.swap(source, target);
+        broadcastChanges();
+        return true;
+    }
+
+    @Override
+    public void clicked(int slotId, int button, ClickType clickType, Player player) {
+        if (!stillValid(player)) {
+            player.closeContainer();
+            return;
+        }
+        if (clickType == ClickType.SWAP
+                && (button == openedHotbarSlot && hand == InteractionHand.MAIN_HAND
+                        || button == 40 && hand == InteractionHand.OFF_HAND)) {
+            return;
+        }
+        super.clicked(slotId, button, clickType, player);
+    }
+
+    private static final class PageSlot extends Slot {
+        private PageSlot(Container container, int slot, int x, int y) {
+            super(container, slot, x, y);
+        }
+
+        @Override public boolean mayPlace(ItemStack stack) { return stack.is(ModItems.PAGE.get()); }
+        @Override public int getMaxStackSize() { return 1; }
+    }
+
+    private static final class LockedSlot extends Slot {
+        private LockedSlot(Container container, int slot, int x, int y) {
+            super(container, slot, x, y);
+        }
+
+        @Override public boolean mayPickup(Player player) { return false; }
+        @Override public boolean mayPlace(ItemStack stack) { return false; }
+    }
+
+    private static final class NotebookContainer extends SimpleContainer {
+        private final Inventory inventory;
+        private final InteractionHand hand;
+        private boolean loading;
+
+        private NotebookContainer(Inventory inventory, InteractionHand hand) {
+            super(NOTEBOOK_SLOTS);
+            this.inventory = inventory;
+            this.hand = hand;
+            ItemStack notebook = inventory.player.getItemInHand(hand);
+            loading = true;
+            List<ItemStack> saved = notebook.getOrDefault(
+                    ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+            for (int index = 0; index < saved.size(); index++) {
+                super.setItem(index, saved.get(index).copy());
+            }
+            loading = false;
+        }
+
+        private void swap(int first, int second) {
+            loading = true;
+            ItemStack held = getItem(first);
+            setItem(first, getItem(second));
+            setItem(second, held);
+            loading = false;
+            setChanged();
+        }
+
+        @Override
+        public void setChanged() {
+            super.setChanged();
+            ItemStack notebook = inventory.player.getItemInHand(hand);
+            if (loading || !notebook.is(ModItems.NOTEBOOK.get())) {
+                return;
+            }
+            NonNullList<ItemStack> saved = NonNullList.withSize(NOTEBOOK_SLOTS, ItemStack.EMPTY);
+            for (int index = 0; index < NOTEBOOK_SLOTS; index++) {
+                ItemStack page = getItem(index);
+                saved.set(index, page.isEmpty() ? ItemStack.EMPTY : page.copyWithCount(1));
+            }
+            notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(saved));
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/menu/WritingDeskMenu.java

@@ -0,0 +1,447 @@
+package net.dnorberg.rivencraft.menu;
+
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.registry.ModMenus;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
+import net.dnorberg.rivencraft.network.WritingDeskCatalogPayload;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.level.ServerPlayer;
+import net.neoforged.neoforge.network.PacketDistributor;
+import java.util.List;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.world.Container;
+import net.minecraft.world.SimpleContainer;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.DataSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+public final class WritingDeskMenu extends AbstractContainerMenu {
+    public static final int COPY_RESULT = WritingDeskBlockEntity.SIZE;
+    public static final int VISIBLE_TABS = 4;
+    public static final int PREVIOUS_TABS = 90;
+    public static final int NEXT_TABS = 91;
+    public static final int PAGE_BUTTON_BASE = 128;
+    public static final int CATALOG_BUTTON_BASE = 512;
+    public static final int ALL_PAGE_BUTTON_BASE = 32768;
+    public static final int PLACE_PAGE_BUTTON_BASE = 65536;
+    private static final int PAGE_ADDRESS_COUNT = WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES;
+    public static final int MOVE_PAGE_BUTTON_BASE = PLACE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT;
+    private static final int PLAYER_START = COPY_RESULT + 1;
+    private static final int EXTRACT_TARGET_COUNT = PLAYER_START + 36 + 1;
+    public static final int EXTRACT_PAGE_BUTTON_BASE = MOVE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * PAGE_ADDRESS_COUNT;
+    private final Container desk;
+    private final WritingDeskBlockEntity blockEntity;
+    private final SimpleContainer result = new SimpleContainer(1);
+    private final boolean clientSide;
+    private int syncedActiveCollection;
+    private int syncedInkRemaining;
+    private int firstVisibleTab;
+    private int selectedPage;
+    private int selectedCollection = -1;
+    private ResourceLocation selectedSymbol;
+    private List<SymbolDisplayMetadata> catalog = List.of();
+    private final ServerPlayer serverViewer;
+
+    public WritingDeskMenu(int id, Inventory inventory, RegistryFriendlyByteBuf data) {
+        this(id, inventory, inventory.player.level().getBlockEntity(data.readBlockPos())
+                instanceof WritingDeskBlockEntity found ? found : null);
+        catalog = WritingDeskCatalog.read(data);
+    }
+
+    public WritingDeskMenu(int id, Inventory inventory, WritingDeskBlockEntity blockEntity) {
+        super(ModMenus.WRITING_DESK.get(), id);
+        this.blockEntity = blockEntity;
+        this.desk = blockEntity == null ? new SimpleContainer(WritingDeskBlockEntity.SIZE) : blockEntity;
+        this.clientSide = inventory.player.level().isClientSide;
+        this.serverViewer = inventory.player instanceof ServerPlayer serverPlayer ? serverPlayer : null;
+        if (blockEntity != null && !clientSide) catalog = WritingDeskCatalog.available(blockEntity);
+        firstVisibleTab = blockEntity == null ? 0 : blockEntity.activeCollection() / VISIBLE_TABS * VISIBLE_TABS;
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return firstVisibleTab; }
+            @Override public void set(int value) { firstVisibleTab = value; }
+        });
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return WritingDeskMenu.this.blockEntity == null
+                    ? syncedActiveCollection : WritingDeskMenu.this.blockEntity.activeCollection(); }
+            @Override public void set(int value) { syncedActiveCollection = value; }
+        });
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return WritingDeskMenu.this.blockEntity == null
+                    ? syncedInkRemaining : WritingDeskMenu.this.blockEntity.inkRemaining(); }
+            @Override public void set(int value) { syncedInkRemaining = value; }
+        });
+        for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++) {
+            addSlot(new DeskSlot(desk, i, 37, 34 + (i % VISIBLE_TABS) * 37, 1));
+        }
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.INK, 385, 28, 16));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.RETURN, 385, 80, 64));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.PAPER, 241, 28, 64));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.LEGACY_OUTPUT, -1000, -1000, 64));
+        addSlot(new CopySlot(result, 0, 241, 80));
+        for (int row = 0; row < 3; row++) {
+            for (int column = 0; column < 9; column++) {
+                addSlot(new Slot(inventory, column + row * 9 + 9, 241 + column * 18, 104 + row * 18));
+            }
+        }
+        for (int column = 0; column < 9; column++) {
+            addSlot(new Slot(inventory, column, 241 + column * 18, 162));
+        }
+    }
+
+    public int activeCollection() { return syncedActiveCollection; }
+    public int firstVisibleTab() { return firstVisibleTab; }
+    public int inkRemaining() { return syncedInkRemaining; }
+    public int pageCapacity(int collectionIndex) {
+        if (collectionIndex < 0 || collectionIndex >= WritingDeskBlockEntity.COLLECTIONS) return 0;
+        ItemStack collection = desk.getItem(collectionIndex);
+        return collection.is(ModItems.NOTEBOOK.get()) ? NotebookContents.MAX_PAGES
+                : collection.is(ModItems.PAGE.get()) ? 1 : 0;
+    }
+    public List<SymbolDisplayMetadata> catalog() { return catalog; }
+    public void setCatalog(List<SymbolDisplayMetadata> symbols) { catalog = List.copyOf(symbols); }
+
+    public static int movePageButtonId(int sourceCollection, int sourcePage, int targetCollection, int targetPage) {
+        int source = sourceCollection * NotebookContents.MAX_PAGES + sourcePage;
+        int target = targetCollection * NotebookContents.MAX_PAGES + targetPage;
+        return MOVE_PAGE_BUTTON_BASE + source * PAGE_ADDRESS_COUNT + target;
+    }
+
+    /** targetSlot is -1 for the cursor, otherwise a visible player or desk-tab slot. */
+    public static int extractPageButtonId(int sourceCollection, int sourcePage, int targetSlot) {
+        int source = sourceCollection * NotebookContents.MAX_PAGES + sourcePage;
+        return EXTRACT_PAGE_BUTTON_BASE + source * EXTRACT_TARGET_COUNT + targetSlot + 1;
+    }
+
+    @Override public boolean clickMenuButton(Player player, int id) {
+        if (blockEntity == null || !stillValid(player)) return false;
+        if (id == PREVIOUS_TABS || id == NEXT_TABS) {
+            firstVisibleTab = Math.clamp(firstVisibleTab + (id == NEXT_TABS ? VISIBLE_TABS : -VISIBLE_TABS),
+                    0, WritingDeskBlockEntity.COLLECTIONS - VISIBLE_TABS);
+            return true;
+        } else if (id >= 0 && id < WritingDeskBlockEntity.COLLECTIONS) {
+            if (id < firstVisibleTab || id >= firstVisibleTab + VISIBLE_TABS) return false;
+            blockEntity.setActiveCollection(id);
+            selectedPage = 0;
+            selectedCollection = -1;
+            selectedSymbol = null;
+        } else if (id >= EXTRACT_PAGE_BUTTON_BASE
+                && id < EXTRACT_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * EXTRACT_TARGET_COUNT) {
+            int offset = id - EXTRACT_PAGE_BUTTON_BASE;
+            int source = offset / EXTRACT_TARGET_COUNT;
+            int targetSlot = offset % EXTRACT_TARGET_COUNT - 1;
+            if (!extractPage(source / NotebookContents.MAX_PAGES, source % NotebookContents.MAX_PAGES,
+                    targetSlot)) return false;
+        } else if (id >= MOVE_PAGE_BUTTON_BASE && id < MOVE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * PAGE_ADDRESS_COUNT) {
+            int offset = id - MOVE_PAGE_BUTTON_BASE;
+            int source = offset / PAGE_ADDRESS_COUNT;
+            int target = offset % PAGE_ADDRESS_COUNT;
+            if (!movePage(source / NotebookContents.MAX_PAGES, source % NotebookContents.MAX_PAGES,
+                    target / NotebookContents.MAX_PAGES, target % NotebookContents.MAX_PAGES)) return false;
+        } else if (id >= PLACE_PAGE_BUTTON_BASE
+                && id < PLACE_PAGE_BUTTON_BASE + WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES) {
+            int offset = id - PLACE_PAGE_BUTTON_BASE;
+            if (!placeCarriedPage(offset / NotebookContents.MAX_PAGES, offset % NotebookContents.MAX_PAGES)) return false;
+        } else if (id >= PAGE_BUTTON_BASE && id < PAGE_BUTTON_BASE + NotebookContents.MAX_PAGES) {
+            selectedPage = id - PAGE_BUTTON_BASE;
+            selectedCollection = -1;
+            selectedSymbol = null;
+        } else if (id >= ALL_PAGE_BUTTON_BASE && id < ALL_PAGE_BUTTON_BASE + WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES) {
+            int offset = id - ALL_PAGE_BUTTON_BASE;
+            int collection = offset / NotebookContents.MAX_PAGES;
+            int page = offset % NotebookContents.MAX_PAGES;
+            if (pageAt(collection, page).isEmpty()) return false;
+            selectedCollection = collection;
+            selectedPage = page;
+            selectedSymbol = null;
+        } else if (id >= CATALOG_BUTTON_BASE && id < CATALOG_BUTTON_BASE + catalog.size()) {
+            if (!catalog.equals(WritingDeskCatalog.available(blockEntity))) {
+                refreshCatalog();
+                return false;
+            }
+            ResourceLocation requested = catalog.get(id - CATALOG_BUTTON_BASE).id();
+            if (!WritingDeskCatalog.available(blockEntity).stream().anyMatch(entry -> entry.id().equals(requested))) {
+                return false;
+            }
+            selectedSymbol = requested;
+        } else return false;
+        refreshOutput();
+        return true;
+    }
+
+    private boolean placeCarriedPage(int collectionIndex, int pageIndex) {
+        // Resolve the actual storage position on the server, never a filtered list index.
+        ItemStack carried = getCarried();
+        if (clientSide || !carried.is(ModItems.PAGE.get())) return false;
+        ItemStack collection = desk.getItem(collectionIndex);
+        if (collection.is(ModItems.NOTEBOOK.get())) {
+            var pages = new java.util.ArrayList<>(collection.getOrDefault(
+                    ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages());
+            while (pages.size() <= pageIndex) pages.add(ItemStack.EMPTY);
+            if (!pages.get(pageIndex).isEmpty()) return false;
+            pages.set(pageIndex, carried.copyWithCount(1));
+            ItemStack updated = collection.copy();
+            updated.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(pages));
+            desk.setItem(collectionIndex, updated);
+        } else return false;
+        carried.shrink(1);
+        setCarried(carried.isEmpty() ? ItemStack.EMPTY : carried);
+        selectedCollection = collectionIndex;
+        selectedPage = pageIndex;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
+    private boolean movePage(int sourceCollection, int sourcePage, int targetCollection, int targetPage) {
+        if (!getCarried().isEmpty() || sourceCollection == targetCollection && sourcePage == targetPage) return false;
+        ItemStack sourceBook = desk.getItem(sourceCollection);
+        ItemStack targetBook = desk.getItem(targetCollection);
+        boolean sourceNotebook = sourceBook.is(ModItems.NOTEBOOK.get());
+        boolean targetNotebook = targetBook.is(ModItems.NOTEBOOK.get());
+        if ((!sourceNotebook && (!sourceBook.is(ModItems.PAGE.get()) || sourcePage != 0))
+                || (!targetNotebook && (!targetBook.is(ModItems.PAGE.get()) || targetPage != 0))) return false;
+        var sourcePages = sourceNotebook ? new java.util.ArrayList<>(sourceBook.getOrDefault(
+                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (sourceNotebook && (sourcePage >= sourcePages.size() || sourcePages.get(sourcePage).isEmpty())) return false;
+        ItemStack moving = sourceNotebook ? sourcePages.get(sourcePage) : sourceBook;
+        if (moving.getCount() != 1) return false;
+        if (!targetNotebook && targetBook.getCount() != 1) return false;
+        var targetPages = targetNotebook ? sourceCollection == targetCollection ? sourcePages
+                : new java.util.ArrayList<>(targetBook.getOrDefault(
+                        ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (targetNotebook) while (targetPages.size() <= targetPage) targetPages.add(ItemStack.EMPTY);
+        ItemStack displaced = targetNotebook ? targetPages.get(targetPage) : targetBook;
+        if (targetNotebook) targetPages.set(targetPage, moving);
+        if (sourceNotebook) {
+            sourcePages.set(sourcePage, displaced);
+            ItemStack updatedSource = sourceBook.copy();
+            updatedSource.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(sourcePages));
+            desk.setItem(sourceCollection, updatedSource);
+        } else desk.setItem(sourceCollection, displaced.isEmpty() ? ItemStack.EMPTY : displaced.copyWithCount(1));
+        if (targetNotebook && sourceCollection != targetCollection) {
+            ItemStack updatedTarget = targetBook.copy();
+            updatedTarget.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(targetPages));
+            desk.setItem(targetCollection, updatedTarget);
+        } else if (!targetNotebook) desk.setItem(targetCollection, moving.copyWithCount(1));
+        selectedCollection = targetCollection;
+        selectedPage = targetPage;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
+    private boolean extractPage(int sourceCollection, int sourcePage, int targetSlot) {
+        if (!getCarried().isEmpty() || targetSlot < -1 || targetSlot >= slots.size()) return false;
+        ItemStack sourceBook = desk.getItem(sourceCollection);
+        boolean sourceNotebook = sourceBook.is(ModItems.NOTEBOOK.get());
+        if (!sourceNotebook && (!sourceBook.is(ModItems.PAGE.get()) || sourcePage != 0)) return false;
+        var sourcePages = sourceNotebook ? new java.util.ArrayList<>(sourceBook.getOrDefault(
+                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (sourceNotebook && (sourcePage >= sourcePages.size() || sourcePages.get(sourcePage).isEmpty())) return false;
+        ItemStack moving = sourceNotebook ? sourcePages.get(sourcePage).copyWithCount(1) : sourceBook.copyWithCount(1);
+        if (!sourceNotebook && sourceBook.getCount() != 1) return false;
+
+        if (targetSlot == -1) {
+            setCarried(moving);
+        } else {
+            if (targetSlot >= WritingDeskBlockEntity.COLLECTIONS && targetSlot < PLAYER_START) return false;
+            Slot target = slots.get(targetSlot);
+            if (!target.isActive() || !target.mayPlace(moving)) return false;
+            ItemStack current = target.getItem();
+            if (targetSlot < WritingDeskBlockEntity.COLLECTIONS && current.is(ModItems.NOTEBOOK.get())) {
+                var targetPages = targetSlot == sourceCollection ? sourcePages
+                        : new java.util.ArrayList<>(current.getOrDefault(
+                                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages());
+                int position = -1;
+                for (int i = 0; i < NotebookContents.MAX_PAGES; i++) {
+                    if (i >= targetPages.size() || targetPages.get(i).isEmpty()) {
+                        position = i;
+                        break;
+                    }
+                }
+                if (position < 0) return false;
+                while (targetPages.size() <= position) targetPages.add(ItemStack.EMPTY);
+                targetPages.set(position, moving);
+                if (targetSlot != sourceCollection) {
+                    ItemStack updatedTarget = current.copy();
+                    updatedTarget.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(targetPages));
+                    target.setByPlayer(updatedTarget);
+                }
+            } else if (current.isEmpty()) {
+                target.setByPlayer(moving);
+            } else if (targetSlot >= PLAYER_START && ItemStack.isSameItemSameComponents(current, moving)
+                    && current.getCount() < target.getMaxStackSize(moving)) {
+                target.setByPlayer(current.copyWithCount(current.getCount() + 1));
+            } else return false;
+        }
+
+        if (sourceNotebook) {
+            sourcePages.set(sourcePage, ItemStack.EMPTY);
+            ItemStack updatedSource = sourceBook.copy();
+            updatedSource.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(sourcePages));
+            desk.setItem(sourceCollection, updatedSource);
+        } else desk.setItem(sourceCollection, ItemStack.EMPTY);
+        selectedCollection = sourceCollection;
+        selectedPage = sourcePage;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
+    @Override public boolean stillValid(Player player) {
+        return blockEntity != null && blockEntity.stillValid(player);
+    }
+
+    @Override public ItemStack quickMoveStack(Player player, int index) {
+        if (!stillValid(player) || index < 0 || index >= slots.size()) return ItemStack.EMPTY;
+        if (index == COPY_RESULT) {
+            refreshOutput();
+            if (!canCopy()) return ItemStack.EMPTY;
+            ItemStack copy = selectedSource().copyWithCount(1);
+            ItemStack movingCopy = copy.copy();
+            if (!moveItemStackTo(movingCopy, PLAYER_START, slots.size(), true) || !movingCopy.isEmpty()) {
+                return ItemStack.EMPTY;
+            }
+            blockEntity.consumeCopyMaterials();
+            refreshOutput();
+            return copy;
+        }
+        Slot slot = slots.get(index);
+        if (!slot.isActive()) return ItemStack.EMPTY;
+        if (!slot.hasItem()) return ItemStack.EMPTY;
+        ItemStack moving = slot.getItem();
+        ItemStack original = moving.copy();
+        if (index < COPY_RESULT) {
+            if (!moveItemStackTo(moving, PLAYER_START, slots.size(), true)) return ItemStack.EMPTY;
+        } else if (!moveIntoDesk(moving)) {
+            return ItemStack.EMPTY;
+        }
+        if (moving.isEmpty()) slot.setByPlayer(ItemStack.EMPTY);
+        else slot.setChanged();
+        return original;
+    }
+
+    private boolean moveIntoDesk(ItemStack moving) {
+        if (moving.is(ModItems.INK_VIAL.get())) return moveItemStackTo(moving,
+                WritingDeskBlockEntity.INK, WritingDeskBlockEntity.INK + 1, false);
+        if (moving.is(ModItems.NOTEBOOK.get())) return moveItemStackTo(moving, firstVisibleTab, firstVisibleTab + VISIBLE_TABS, false);
+        if (moving.is(Items.PAPER))
+            return moveItemStackTo(moving, WritingDeskBlockEntity.PAPER,
+                    WritingDeskBlockEntity.PAPER + 1, false);
+        if (moving.is(ModItems.PAGE.get())) return moveItemStackTo(moving, firstVisibleTab, firstVisibleTab + VISIBLE_TABS, false);
+        return false;
+    }
+
+    private ItemStack selectedSource() {
+        if (selectedSymbol != null) {
+            SymbolReference reference = new SymbolReference(selectedSymbol);
+            return SymbolCatalog.isKnown(reference)
+                    && blockEntity != null
+                    && WritingDeskCatalog.available(blockEntity).stream()
+                    .anyMatch(entry -> entry.id().equals(selectedSymbol))
+                    ? PageItem.createSymbolPage(reference) : ItemStack.EMPTY;
+        }
+        int collectionIndex = selectedCollection >= 0 ? selectedCollection
+                : blockEntity == null ? syncedActiveCollection : blockEntity.activeCollection();
+        return pageAt(collectionIndex, selectedPage);
+    }
+
+    private ItemStack pageAt(int collectionIndex, int pageIndex) {
+        if (collectionIndex < 0 || collectionIndex >= WritingDeskBlockEntity.COLLECTIONS
+                || pageIndex < 0 || pageIndex >= NotebookContents.MAX_PAGES) return ItemStack.EMPTY;
+        ItemStack collection = desk.getItem(collectionIndex);
+        if (collection.is(ModItems.PAGE.get())) return pageIndex == 0 ? collection : ItemStack.EMPTY;
+        if (collection.is(ModItems.NOTEBOOK.get())) {
+            List<ItemStack> pages = collection.getOrDefault(
+                    ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+            return pageIndex < pages.size() ? pages.get(pageIndex) : ItemStack.EMPTY;
+        }
+        return ItemStack.EMPTY;
+    }
+
+    private boolean canCopy() {
+        ItemStack source = selectedSource();
+        return blockEntity != null && source.is(ModItems.PAGE.get())
+                && PageItem.content(source).kind() != PageContent.Kind.BLANK
+                && PageItem.isUsableWriting(source) && blockEntity.canConsumeCopyMaterials();
+    }
+
+    private void refreshOutput() {
+        if (clientSide) return;
+        if (blockEntity != null) blockEntity.setDisplayPage(selectedSource());
+        ItemStack preview = canCopy() ? selectedSource().copyWithCount(1) : ItemStack.EMPTY;
+        if (!ItemStack.matches(result.getItem(0), preview)) result.setItem(0, preview);
+    }
+
+    private void refreshCatalog() {
+        if (clientSide || blockEntity == null) return;
+        List<SymbolDisplayMetadata> current = WritingDeskCatalog.available(blockEntity);
+        if (!current.equals(catalog)) {
+            catalog = current;
+            if (serverViewer != null && serverViewer.containerMenu == this) {
+                PacketDistributor.sendToPlayer(serverViewer, new WritingDeskCatalogPayload(containerId, catalog));
+            }
+        }
+    }
+
+    @Override public void broadcastChanges() {
+        refreshCatalog();
+        refreshOutput();
+        super.broadcastChanges();
+    }
+
+    @Override public void clicked(int slotId, int button, net.minecraft.world.inventory.ClickType clickType,
+                                  Player player) {
+        if (!stillValid(player)) {
+            player.closeContainer();
+            return;
+        }
+        refreshCatalog();
+        refreshOutput();
+        if (slotId >= 0 && slotId < slots.size() && !slots.get(slotId).isActive()) return;
+        super.clicked(slotId, button, clickType, player);
+    }
+
+    private final class CopySlot extends Slot {
+        private CopySlot(Container container, int index, int x, int y) { super(container, index, x, y); }
+        @Override public boolean mayPlace(ItemStack stack) { return false; }
+        @Override public boolean mayPickup(Player player) {
+            return clientSide ? hasItem() : WritingDeskMenu.this.stillValid(player) && canCopy();
+        }
+        @Override public void onTake(Player player, ItemStack stack) {
+            if (!clientSide && blockEntity.consumeCopyMaterials()) refreshOutput();
+            super.onTake(player, stack);
+        }
+    }
+
+    private final class DeskSlot extends Slot {
+        private final int limit;
+        private DeskSlot(Container container, int index, int x, int y, int limit) {
+            super(container, index, x, y);
+            this.limit = limit;
+        }
+        @Override public boolean isActive() {
+            int slot = getContainerSlot();
+            return slot >= WritingDeskBlockEntity.COLLECTIONS
+                    || slot >= firstVisibleTab && slot < firstVisibleTab + VISIBLE_TABS;
+        }
+        @Override public boolean mayPickup(Player player) { return isActive(); }
+        @Override public boolean mayPlace(ItemStack stack) { return isActive() && container.canPlaceItem(getContainerSlot(), stack); }
+        @Override public int getMaxStackSize() { return limit; }
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/ClientLevelSoundMixin.java

@@ -0,0 +1,59 @@
+package net.dnorberg.rivencraft.mixin.client;
+
+import net.dnorberg.rivencraft.client.preview.ImmersivePortalsPreviewAudioGuard;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.core.Holder;
+import net.minecraft.sounds.SoundEvent;
+import net.minecraft.sounds.SoundSource;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.player.Player;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/** Mutes only the remote client world displayed by a Rivencraft book preview. */
+@Mixin(value = ClientLevel.class, priority = 2000)
+public abstract class ClientLevelSoundMixin {
+    @Inject(
+            method = "playSound(DDDLnet/minecraft/sounds/SoundEvent;Lnet/minecraft/sounds/SoundSource;FFZJ)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewPositionSound(
+            double x, double y, double z, SoundEvent sound, SoundSource source,
+            float volume, float pitch, boolean distanceDelay, long seed, CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    @Inject(
+            method = "playLocalSound(Lnet/minecraft/world/entity/Entity;Lnet/minecraft/sounds/SoundEvent;Lnet/minecraft/sounds/SoundSource;FF)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewLocalEntitySound(
+            Entity entity, SoundEvent sound, SoundSource source, float volume, float pitch,
+            CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    @Inject(
+            method = "playSeededSound(Lnet/minecraft/world/entity/player/Player;Lnet/minecraft/world/entity/Entity;Lnet/minecraft/core/Holder;Lnet/minecraft/sounds/SoundSource;FFJ)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewSeededEntitySound(
+            Player player, Entity entity, Holder<SoundEvent> sound, SoundSource source,
+            float volume, float pitch, long seed, CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    private void rivencraft$cancelPreviewSound(CallbackInfo callback) {
+        if (ImmersivePortalsPreviewAudioGuard.shouldMute((ClientLevel)(Object)this)) {
+            callback.cancel();
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/ImmersivePortalsGuiRenderingMixin.java

@@ -0,0 +1,18 @@
+package net.dnorberg.rivencraft.mixin.client;
+
+import net.dnorberg.rivencraft.client.preview.ImmersivePortalsPreviewAudioGuard;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Pseudo;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/** Restores the player camera after Immersive Portals finishes GUI-world rendering. */
+@Pseudo
+@Mixin(targets = "qouteall.imm_ptl.core.render.GuiPortalRendering", remap = false)
+public abstract class ImmersivePortalsGuiRenderingMixin {
+    @Inject(method = "_onGameRenderEnd", at = @At("RETURN"), remap = false)
+    private static void rivencraft$restorePlayerCamera(CallbackInfo callback) {
+        ImmersivePortalsPreviewAudioGuard.restorePlayerCamera();
+    }
+}

src/main/java/net/dnorberg/rivencraft/network/ModNetworking.java

@@ -9,6 +9,7 @@ import net.dnorberg.rivencraft.block.entity.BookStandBlockEntity;
 import net.dnorberg.rivencraft.client.ClientLinkPreviewHandler;
 import net.dnorberg.rivencraft.client.ClientBookInteractionHandler;
 import net.dnorberg.rivencraft.client.ClientAgeCelestialAngles;
+import net.dnorberg.rivencraft.client.ClientWritingDeskCatalog;
 import net.dnorberg.rivencraft.event.AgeCelestialAngleSync;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
 import net.dnorberg.rivencraft.item.LinkingBookItem;
@@ -48,7 +49,7 @@ public final class ModNetworking {
     }
 
     public static void register(RegisterPayloadHandlersEvent event) {
-        PayloadRegistrar registrar = event.registrar("9");
+        PayloadRegistrar registrar = event.registrar("11");
         registrar.playToServer(RequestDescriptiveBookScreenPayload.TYPE, RequestDescriptiveBookScreenPayload.STREAM_CODEC,
                 ModNetworking::requestDescriptiveBookScreen);
         registrar.playToClient(OpenDescriptiveBookScreenPayload.TYPE, OpenDescriptiveBookScreenPayload.STREAM_CODEC,
@@ -68,6 +69,8 @@ public final class ModNetworking {
                 ClientLinkPreviewHandler::handle);
         registrar.playToClient(AgeCelestialAnglePayload.TYPE, AgeCelestialAnglePayload.STREAM_CODEC,
                 ClientAgeCelestialAngles::handle);
+        registrar.playToClient(WritingDeskCatalogPayload.TYPE, WritingDeskCatalogPayload.STREAM_CODEC,
+                ClientWritingDeskCatalog::handle);
     }
 
     private static void requestDescriptiveBookScreen(RequestDescriptiveBookScreenPayload payload, IPayloadContext context) {

src/main/java/net/dnorberg/rivencraft/network/WritingDeskCatalogPayload.java

@@ -0,0 +1,26 @@
+package net.dnorberg.rivencraft.network;
+
+import java.util.List;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceLocation;
+
+/** Current server-approved symbols from this open Writing Desk menu. */
+public record WritingDeskCatalogPayload(int containerId, List<SymbolDisplayMetadata> symbols)
+        implements CustomPacketPayload {
+    public static final Type<WritingDeskCatalogPayload> TYPE = new Type<>(
+            ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "writing_desk_catalog"));
+    public static final StreamCodec<RegistryFriendlyByteBuf, WritingDeskCatalogPayload> STREAM_CODEC =
+            StreamCodec.of(
+                    (buffer, payload) -> {
+                        buffer.writeVarInt(payload.containerId());
+                        WritingDeskCatalog.write(buffer, payload.symbols());
+                    },
+                    buffer -> new WritingDeskCatalogPayload(buffer.readVarInt(), WritingDeskCatalog.read(buffer)));
+
+    @Override public Type<? extends CustomPacketPayload> type() { return TYPE; }
+}

src/main/java/net/dnorberg/rivencraft/registry/ModBlockEntities.java

@@ -2,6 +2,7 @@ package net.dnorberg.rivencraft.registry;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.block.entity.BookStandBlockEntity;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.neoforged.bus.api.IEventBus;
@@ -16,6 +17,9 @@ public final class ModBlockEntities {
             BLOCK_ENTITIES.register("book_stand", () -> BlockEntityType.Builder
                     .of(BookStandBlockEntity::new, ModBlocks.BOOK_STAND.get())
                     .build(null));
+    public static final DeferredHolder<BlockEntityType<?>, BlockEntityType<WritingDeskBlockEntity>> WRITING_DESK =
+            BLOCK_ENTITIES.register("writing_desk", () -> BlockEntityType.Builder
+                    .of(WritingDeskBlockEntity::new, ModBlocks.WRITING_DESK.get()).build(null));
 
     private ModBlockEntities() {
     }

src/main/java/net/dnorberg/rivencraft/registry/ModBlocks.java

@@ -2,6 +2,7 @@ package net.dnorberg.rivencraft.registry;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.block.BookStandBlock;
+import net.dnorberg.rivencraft.block.WritingDeskBlock;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.state.BlockBehaviour;
 import net.neoforged.bus.api.IEventBus;
@@ -16,6 +17,10 @@ public final class ModBlocks {
             BookStandBlock::new,
             BlockBehaviour.Properties.ofFullCopy(Blocks.LECTERN)
     );
+    public static final DeferredBlock<WritingDeskBlock> WRITING_DESK = BLOCKS.registerBlock(
+            "writing_desk", WritingDeskBlock::new,
+            BlockBehaviour.Properties.ofFullCopy(Blocks.CRAFTING_TABLE).noOcclusion()
+    );
 
     private ModBlocks() {
     }

src/main/java/net/dnorberg/rivencraft/registry/ModCreativeTabs.java

@@ -1,6 +1,7 @@
 package net.dnorberg.rivencraft.registry;
 
 import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.item.PageItem;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.item.CreativeModeTab;
@@ -19,6 +20,18 @@ public final class ModCreativeTabs {
                     .displayItems((parameters, output) -> {
                         output.accept(ModItems.DESCRIPTIVE_BOOK.get());
                         output.accept(ModItems.LINKING_BOOK.get());
+                        output.accept(ModItems.NOTEBOOK.get());
+                        output.accept(ModItems.INK_VIAL.get());
+                        output.accept(ModItems.WRITING_DESK.get());
+                    })
+                    .build());
+
+    public static final DeferredHolder<CreativeModeTab, CreativeModeTab> PAGES =
+            CREATIVE_TABS.register("rivencraft_pages", () -> CreativeModeTab.builder()
+                    .title(Component.translatable("itemGroup.rivencraft.pages"))
+                    .icon(PageItem::createLinkPanelPage)
+                    .displayItems((parameters, output) -> {
+                        output.accept(PageItem.createLinkPanelPage());
                     })
                     .build());
 

src/main/java/net/dnorberg/rivencraft/registry/ModDataComponents.java

@@ -3,6 +3,10 @@ package net.dnorberg.rivencraft.registry;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.AgeReference;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.NotebookContents;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import com.mojang.serialization.Codec;
 import net.minecraft.core.component.DataComponentType;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceLocation;
@@ -39,6 +43,30 @@ public final class ModDataComponents {
                     .networkSynchronized(ByteBufCodecs.STRING_UTF8)
                     .cacheEncoding()
                     .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<PageContent>> PAGE_CONTENT =
+            DATA_COMPONENTS.register("page_content", () -> DataComponentType.<PageContent>builder()
+                    .persistent(PageContent.CODEC)
+                    .networkSynchronized(PageContent.STREAM_CODEC)
+                    .cacheEncoding()
+                    .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<SymbolDisplayMetadata>> PAGE_SYMBOL_DISPLAY =
+            DATA_COMPONENTS.register("page_symbol_display", () -> DataComponentType.<SymbolDisplayMetadata>builder()
+                    .persistent(SymbolDisplayMetadata.CODEC)
+                    .networkSynchronized(SymbolDisplayMetadata.STREAM_CODEC)
+                    .cacheEncoding()
+                    .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<NotebookContents>> NOTEBOOK_CONTENTS =
+            DATA_COMPONENTS.register("notebook_contents", () -> DataComponentType.<NotebookContents>builder()
+                    .persistent(NotebookContents.CODEC)
+                    .networkSynchronized(NotebookContents.STREAM_CODEC)
+                    .cacheEncoding()
+                    .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<Integer>> INK_REMAINING =
+            DATA_COMPONENTS.register("ink_remaining", () -> DataComponentType.<Integer>builder()
+                    .persistent(Codec.intRange(0, 16))
+                    .networkSynchronized(ByteBufCodecs.VAR_INT)
+                    .cacheEncoding()
+                    .build());
 
     private ModDataComponents() {
     }

src/main/java/net/dnorberg/rivencraft/registry/ModItems.java

@@ -3,7 +3,11 @@ package net.dnorberg.rivencraft.registry;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
 import net.dnorberg.rivencraft.item.LinkingBookItem;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.item.NotebookItem;
+import net.dnorberg.rivencraft.item.InkVialItem;
 import net.minecraft.world.item.Item;
+import net.minecraft.world.item.BlockItem;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.neoforge.registries.DeferredItem;
 import net.neoforged.neoforge.registries.DeferredRegister;
@@ -21,6 +25,22 @@ public final class ModItems {
             LinkingBookItem::new,
             new Item.Properties().stacksTo(1)
     );
+    public static final DeferredItem<PageItem> PAGE = ITEMS.registerItem(
+            "page",
+            PageItem::new,
+            new Item.Properties().stacksTo(64)
+    );
+    public static final DeferredItem<NotebookItem> NOTEBOOK = ITEMS.registerItem(
+            "notebook",
+            NotebookItem::new,
+            new Item.Properties().stacksTo(1)
+    );
+    public static final DeferredItem<InkVialItem> INK_VIAL = ITEMS.registerItem(
+            "ink_vial",
+            InkVialItem::new,
+            new Item.Properties().stacksTo(16)
+    );
+    public static final DeferredItem<BlockItem> WRITING_DESK = ITEMS.registerSimpleBlockItem(ModBlocks.WRITING_DESK);
 
     private ModItems() {
     }

src/main/java/net/dnorberg/rivencraft/registry/ModMenus.java

@@ -0,0 +1,28 @@
+package net.dnorberg.rivencraft.registry;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.menu.NotebookMenu;
+import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.world.inventory.MenuType;
+import net.neoforged.bus.api.IEventBus;
+import net.neoforged.neoforge.common.extensions.IMenuTypeExtension;
+import net.neoforged.neoforge.registries.DeferredHolder;
+import net.neoforged.neoforge.registries.DeferredRegister;
+
+public final class ModMenus {
+    private static final DeferredRegister<MenuType<?>> MENUS =
+            DeferredRegister.create(Registries.MENU, Rivencraft.MOD_ID);
+
+    public static final DeferredHolder<MenuType<?>, MenuType<NotebookMenu>> NOTEBOOK =
+            MENUS.register("notebook", () -> IMenuTypeExtension.create(NotebookMenu::new));
+    public static final DeferredHolder<MenuType<?>, MenuType<WritingDeskMenu>> WRITING_DESK =
+            MENUS.register("writing_desk", () -> IMenuTypeExtension.create(WritingDeskMenu::new));
+
+    private ModMenus() {
+    }
+
+    public static void register(IEventBus modEventBus) {
+        MENUS.register(modEventBus);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/NotebookContents.java

@@ -0,0 +1,88 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import java.util.ArrayList;
+import java.util.List;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.world.item.ItemStack;
+
+/** A bounded, position-preserving collection of Page stacks stored on a Notebook item. */
+public record NotebookContents(List<ItemStack> pages) {
+    public static final int MAX_PAGES = 27;
+    public static final NotebookContents EMPTY = new NotebookContents(List.of());
+    public static final Codec<NotebookContents> CODEC = ItemStack.OPTIONAL_CODEC.listOf()
+            .validate(NotebookContents::validate)
+            .xmap(NotebookContents::new, NotebookContents::pages);
+    public static final StreamCodec<RegistryFriendlyByteBuf, NotebookContents> STREAM_CODEC = StreamCodec.of(
+            NotebookContents::encode, NotebookContents::decode);
+
+    public NotebookContents {
+        if (pages.size() > MAX_PAGES) {
+            throw new IllegalArgumentException("Notebook exceeds " + MAX_PAGES + " page positions");
+        }
+        List<ItemStack> copies = new ArrayList<>(pages.size());
+        for (ItemStack page : pages) {
+            validatePage(page).getOrThrow();
+            copies.add(page.copy());
+        }
+        pages = List.copyOf(copies);
+    }
+
+    public int pageCount() {
+        return (int)pages.stream().filter(page -> !page.isEmpty()).count();
+    }
+
+    public int unresolvedCount() {
+        return (int)pages.stream()
+                .filter(page -> !page.isEmpty()
+                        && PageContent.Kind.UNRESOLVED_SYMBOL == PageItem.content(page).kind())
+                .count();
+    }
+
+    private static DataResult<List<ItemStack>> validate(List<ItemStack> pages) {
+        if (pages.size() > MAX_PAGES) {
+            return DataResult.error(() -> "Notebook exceeds " + MAX_PAGES + " page positions");
+        }
+        for (ItemStack page : pages) {
+            DataResult<ItemStack> result = validatePage(page);
+            if (result.error().isPresent()) {
+                return DataResult.error(() -> result.error().orElseThrow().message());
+            }
+        }
+        return DataResult.success(pages);
+    }
+
+    private static DataResult<ItemStack> validatePage(ItemStack page) {
+        if (page.isEmpty()) {
+            return DataResult.success(page);
+        }
+        if (!page.is(ModItems.PAGE.get())) {
+            return DataResult.error(() -> "Notebook contains a non-Page item");
+        }
+        return page.getCount() == 1
+                ? DataResult.success(page)
+                : DataResult.error(() -> "Notebook Page stacks must contain exactly one item");
+    }
+
+    private static void encode(RegistryFriendlyByteBuf buffer, NotebookContents contents) {
+        ByteBufCodecs.VAR_INT.encode(buffer, contents.pages.size());
+        contents.pages.forEach(page -> ItemStack.OPTIONAL_STREAM_CODEC.encode(buffer, page));
+    }
+
+    private static NotebookContents decode(RegistryFriendlyByteBuf buffer) {
+        int size = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (size < 0 || size > MAX_PAGES) {
+            throw new IllegalArgumentException("Invalid Notebook page count " + size);
+        }
+        List<ItemStack> pages = new ArrayList<>(size);
+        for (int index = 0; index < size; index++) {
+            pages.add(ItemStack.OPTIONAL_STREAM_CODEC.decode(buffer));
+        }
+        return new NotebookContents(pages);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/OrderedWriting.java

@@ -0,0 +1,47 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import io.netty.buffer.ByteBuf;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** Immutable ordered writing shared by pages, notebooks, desks, and books. */
+public record OrderedWriting(List<WritingEntry> entries) {
+    public static final int MAX_ENTRIES = 256;
+    public static final OrderedWriting EMPTY = new OrderedWriting(List.of());
+    public static final Codec<OrderedWriting> CODEC = WritingEntry.CODEC.listOf()
+            .validate(entries -> entries.size() <= MAX_ENTRIES
+                    ? DataResult.success(entries)
+                    : DataResult.error(() -> "Writing exceeds " + MAX_ENTRIES + " entries"))
+            .xmap(OrderedWriting::new, OrderedWriting::entries);
+    public static final StreamCodec<ByteBuf, OrderedWriting> STREAM_CODEC = StreamCodec.of(
+            OrderedWriting::encode, OrderedWriting::decode);
+
+    public OrderedWriting {
+        entries = List.copyOf(Objects.requireNonNull(entries, "entries"));
+        if (entries.size() > MAX_ENTRIES) {
+            throw new IllegalArgumentException("Writing exceeds " + MAX_ENTRIES + " entries");
+        }
+    }
+
+    private static void encode(ByteBuf buffer, OrderedWriting writing) {
+        ByteBufCodecs.VAR_INT.encode(buffer, writing.entries.size());
+        writing.entries.forEach(entry -> WritingEntry.STREAM_CODEC.encode(buffer, entry));
+    }
+
+    private static OrderedWriting decode(ByteBuf buffer) {
+        int size = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (size < 0 || size > MAX_ENTRIES) {
+            throw new IllegalArgumentException("Invalid writing entry count " + size);
+        }
+        List<WritingEntry> entries = new ArrayList<>(size);
+        for (int index = 0; index < size; index++) {
+            entries.add(WritingEntry.STREAM_CODEC.decode(buffer));
+        }
+        return new OrderedWriting(entries);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/PageContent.java

@@ -0,0 +1,95 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import java.util.Locale;
+import java.util.Objects;
+import java.util.Optional;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** Persistent contents of a Page item. Unknown symbols remain explicit and recoverable. */
+public record PageContent(Kind kind, Optional<SymbolReference> symbol) {
+    public static final PageContent BLANK = new PageContent(Kind.BLANK, Optional.empty());
+    public static final PageContent LINK_PANEL = new PageContent(Kind.LINK_PANEL, Optional.empty());
+    private static final Codec<Kind> KIND_CODEC = Codec.STRING.comapFlatMap(
+            value -> {
+                try {
+                    return DataResult.success(Kind.valueOf(value.toUpperCase(Locale.ROOT)));
+                } catch (IllegalArgumentException exception) {
+                    return DataResult.error(() -> "Unknown page content kind: " + value);
+                }
+            },
+            value -> value.name().toLowerCase(Locale.ROOT)
+    );
+    private static final Codec<PageContent> RECORD_CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            KIND_CODEC.fieldOf("kind").forGetter(PageContent::kind),
+            SymbolReference.CODEC.optionalFieldOf("symbol").forGetter(PageContent::symbol)
+    ).apply(instance, PageContent::new));
+    public static final Codec<PageContent> CODEC = RECORD_CODEC.flatXmap(PageContent::validate, PageContent::validate);
+    public static final StreamCodec<ByteBuf, PageContent> STREAM_CODEC = StreamCodec.of(
+            PageContent::encode, PageContent::decode);
+
+    public PageContent {
+        Objects.requireNonNull(kind, "kind");
+        symbol = Objects.requireNonNull(symbol, "symbol");
+        boolean needsSymbol = kind == Kind.SYMBOL || kind == Kind.UNRESOLVED_SYMBOL;
+        if (needsSymbol != symbol.isPresent()) {
+            throw new IllegalArgumentException("Page contents do not match kind " + kind);
+        }
+    }
+
+    public static PageContent symbol(SymbolReference symbol) {
+        return new PageContent(Kind.SYMBOL, Optional.of(symbol));
+    }
+
+    public static PageContent unresolved(SymbolReference symbol) {
+        return new PageContent(Kind.UNRESOLVED_SYMBOL, Optional.of(symbol));
+    }
+
+    /** Re-resolves persisted data against the authoritative current server catalog. */
+    public PageContent resolve() {
+        if (kind != Kind.SYMBOL && kind != Kind.UNRESOLVED_SYMBOL) {
+            return this;
+        }
+        SymbolReference reference = symbol.orElseThrow();
+        return SymbolCatalog.isKnown(reference) ? symbol(reference) : unresolved(reference);
+    }
+
+    public boolean isResolvedSymbol() {
+        return kind == Kind.SYMBOL;
+    }
+
+    private static DataResult<PageContent> validate(PageContent content) {
+        boolean needsSymbol = content.kind == Kind.SYMBOL || content.kind == Kind.UNRESOLVED_SYMBOL;
+        return needsSymbol == content.symbol.isPresent()
+                ? DataResult.success(content)
+                : DataResult.error(() -> "Page contents do not match kind " + content.kind);
+    }
+
+    private static void encode(ByteBuf buffer, PageContent content) {
+        ByteBufCodecs.VAR_INT.encode(buffer, content.kind.ordinal());
+        content.symbol.ifPresent(reference -> SymbolReference.STREAM_CODEC.encode(buffer, reference));
+    }
+
+    private static PageContent decode(ByteBuf buffer) {
+        int ordinal = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (ordinal < 0 || ordinal >= Kind.values().length) {
+            throw new IllegalArgumentException("Unknown page content kind ordinal " + ordinal);
+        }
+        Kind kind = Kind.values()[ordinal];
+        Optional<SymbolReference> symbol = kind == Kind.SYMBOL || kind == Kind.UNRESOLVED_SYMBOL
+                ? Optional.of(SymbolReference.STREAM_CODEC.decode(buffer))
+                : Optional.empty();
+        return new PageContent(kind, symbol);
+    }
+
+    public enum Kind {
+        BLANK,
+        SYMBOL,
+        UNRESOLVED_SYMBOL,
+        LINK_PANEL
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolCatalog.java

@@ -0,0 +1,67 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import com.mojang.serialization.JsonOps;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.resources.ResourceManager;
+import net.minecraft.server.packs.resources.SimpleJsonResourceReloadListener;
+import net.minecraft.util.profiling.ProfilerFiller;
+import net.neoforged.neoforge.event.AddReloadListenerEvent;
+
+/** Authoritative server catalog loaded from data/<namespace>/rivencraft/symbols. */
+public final class SymbolCatalog {
+    private static final Gson GSON = new GsonBuilder().create();
+    private static final String DIRECTORY = "rivencraft/symbols";
+    private static volatile Map<ResourceLocation, SymbolDefinition> symbols = Map.of();
+
+    private SymbolCatalog() {
+    }
+
+    public static void register(AddReloadListenerEvent event) {
+        event.addListener(new Loader());
+    }
+
+    public static Optional<SymbolDefinition> find(SymbolReference reference) {
+        return Optional.ofNullable(symbols.get(reference.id()));
+    }
+
+    public static boolean isKnown(SymbolReference reference) {
+        return symbols.containsKey(reference.id());
+    }
+
+    public static SymbolDisplayMetadata display(SymbolReference reference) {
+        SymbolDefinition definition = symbols.get(reference.id());
+        return definition == null
+                ? SymbolDisplayMetadata.unresolved(reference)
+                : definition.display(reference.id());
+    }
+
+    public static Map<ResourceLocation, SymbolDefinition> symbols() {
+        return symbols;
+    }
+
+    private static final class Loader extends SimpleJsonResourceReloadListener {
+        private Loader() {
+            super(GSON, DIRECTORY);
+        }
+
+        @Override
+        protected void apply(Map<ResourceLocation, JsonElement> resources,
+                             ResourceManager resourceManager,
+                             ProfilerFiller profiler) {
+            Map<ResourceLocation, SymbolDefinition> loaded = new HashMap<>();
+            resources.forEach((id, json) -> SymbolDefinition.CODEC.parse(JsonOps.INSTANCE, json)
+                    .resultOrPartial(error -> Rivencraft.LOGGER.error(
+                            "Ignoring invalid writing symbol {}: {}", id, error))
+                    .ifPresent(definition -> loaded.put(id, definition)));
+            symbols = Map.copyOf(loaded);
+            Rivencraft.LOGGER.info("Loaded {} writing symbols", loaded.size());
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolDefinition.java

@@ -0,0 +1,47 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import java.util.Objects;
+import java.util.regex.Pattern;
+import net.minecraft.resources.ResourceLocation;
+
+/** Server-loaded, non-executable display metadata for a writing symbol. */
+public record SymbolDefinition(
+        int schemaVersion,
+        String nameTranslationKey,
+        String descriptionTranslationKey,
+        ResourceLocation category
+) {
+    public static final int CURRENT_SCHEMA_VERSION = 1;
+    private static final Pattern TRANSLATION_KEY = Pattern.compile("[a-z0-9_.-]+");
+    private static final Codec<String> TRANSLATION_KEY_CODEC = Codec.STRING.comapFlatMap(
+            value -> TRANSLATION_KEY.matcher(value).matches()
+                    ? DataResult.success(value)
+                    : DataResult.error(() -> "Invalid translation key: " + value),
+            value -> value
+    );
+    public static final Codec<SymbolDefinition> CODEC = RecordCodecBuilder.<SymbolDefinition>create(instance -> instance.group(
+            Codec.INT.fieldOf("schema_version").forGetter(SymbolDefinition::schemaVersion),
+            TRANSLATION_KEY_CODEC.fieldOf("name").forGetter(SymbolDefinition::nameTranslationKey),
+            TRANSLATION_KEY_CODEC.fieldOf("description").forGetter(SymbolDefinition::descriptionTranslationKey),
+            ResourceLocation.CODEC.fieldOf("category").forGetter(SymbolDefinition::category)
+    ).apply(instance, SymbolDefinition::new)).flatXmap(SymbolDefinition::validate, SymbolDefinition::validate);
+
+    public SymbolDefinition {
+        Objects.requireNonNull(nameTranslationKey, "nameTranslationKey");
+        Objects.requireNonNull(descriptionTranslationKey, "descriptionTranslationKey");
+        Objects.requireNonNull(category, "category");
+    }
+
+    public SymbolDisplayMetadata display(ResourceLocation id) {
+        return new SymbolDisplayMetadata(id, nameTranslationKey, descriptionTranslationKey, category, true);
+    }
+
+    private static DataResult<SymbolDefinition> validate(SymbolDefinition definition) {
+        return definition.schemaVersion == CURRENT_SCHEMA_VERSION
+                ? DataResult.success(definition)
+                : DataResult.error(() -> "Unsupported symbol schema_version " + definition.schemaVersion);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolDisplayMetadata.java

@@ -0,0 +1,44 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.resources.ResourceLocation;
+
+/** Client-safe symbol presentation selected by the authoritative server catalog. */
+public record SymbolDisplayMetadata(
+        ResourceLocation id,
+        String nameTranslationKey,
+        String descriptionTranslationKey,
+        ResourceLocation category,
+        boolean resolved
+) {
+    public static final Codec<SymbolDisplayMetadata> CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            ResourceLocation.CODEC.fieldOf("id").forGetter(SymbolDisplayMetadata::id),
+            Codec.STRING.fieldOf("name").forGetter(SymbolDisplayMetadata::nameTranslationKey),
+            Codec.STRING.fieldOf("description").forGetter(SymbolDisplayMetadata::descriptionTranslationKey),
+            ResourceLocation.CODEC.fieldOf("category").forGetter(SymbolDisplayMetadata::category),
+            Codec.BOOL.fieldOf("resolved").forGetter(SymbolDisplayMetadata::resolved)
+    ).apply(instance, SymbolDisplayMetadata::new));
+    public static final StreamCodec<ByteBuf, SymbolDisplayMetadata> STREAM_CODEC = StreamCodec.composite(
+            ResourceLocation.STREAM_CODEC, SymbolDisplayMetadata::id,
+            ByteBufCodecs.STRING_UTF8, SymbolDisplayMetadata::nameTranslationKey,
+            ByteBufCodecs.STRING_UTF8, SymbolDisplayMetadata::descriptionTranslationKey,
+            ResourceLocation.STREAM_CODEC, SymbolDisplayMetadata::category,
+            ByteBufCodecs.BOOL, SymbolDisplayMetadata::resolved,
+            SymbolDisplayMetadata::new
+    );
+
+    public static SymbolDisplayMetadata unresolved(SymbolReference reference) {
+        return new SymbolDisplayMetadata(
+                reference.id(),
+                "symbol.rivencraft.unresolved",
+                "symbol.rivencraft.unresolved.description",
+                ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "unresolved"),
+                false
+        );
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolReference.java

@@ -0,0 +1,24 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import io.netty.buffer.ByteBuf;
+import java.util.Objects;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.resources.ResourceLocation;
+
+/** Stable namespaced identity for one writing symbol. */
+public record SymbolReference(ResourceLocation id) {
+    public static final Codec<SymbolReference> CODEC = ResourceLocation.CODEC.xmap(
+            SymbolReference::new, SymbolReference::id);
+    public static final StreamCodec<ByteBuf, SymbolReference> STREAM_CODEC = ResourceLocation.STREAM_CODEC.map(
+            SymbolReference::new, SymbolReference::id);
+
+    public SymbolReference {
+        Objects.requireNonNull(id, "id");
+    }
+
+    /** Remains useful when the defining data pack has been removed. */
+    public String unresolvedName() {
+        return id.toString();
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/WritingDeskCatalog.java

@@ -0,0 +1,63 @@
+package net.dnorberg.rivencraft.writing;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.item.ItemStack;
+
+/** A bounded, server-derived view of symbols physically present in the desk. */
+public final class WritingDeskCatalog {
+    private static final int MAX_ENTRIES = WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES;
+
+    private WritingDeskCatalog() {}
+
+    public static List<SymbolDisplayMetadata> available(WritingDeskBlockEntity desk) {
+        Map<ResourceLocation, SymbolDisplayMetadata> unique = new TreeMap<>();
+        for (int slot = 0; slot < WritingDeskBlockEntity.COLLECTIONS; slot++) {
+            ItemStack collection = desk.getItem(slot);
+            if (collection.is(ModItems.PAGE.get())) add(unique, collection);
+            if (collection.is(ModItems.NOTEBOOK.get())) {
+                List<ItemStack> pages = collection.getOrDefault(
+                        ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+                pages.forEach(page -> add(unique, page));
+            }
+        }
+        return unique.values().stream()
+                .sorted(Comparator.comparing((SymbolDisplayMetadata symbol) -> symbol.category().toString())
+                        .thenComparing(symbol -> symbol.id().toString()))
+                .toList();
+    }
+
+    private static void add(Map<ResourceLocation, SymbolDisplayMetadata> unique, ItemStack page) {
+        if (!page.is(ModItems.PAGE.get())) return;
+        PageContent content = PageItem.content(page).resolve();
+        if (content.kind() != PageContent.Kind.SYMBOL) return;
+        SymbolReference reference = content.symbol().orElseThrow();
+        SymbolCatalog.find(reference).ifPresent(definition ->
+                unique.put(reference.id(), definition.display(reference.id())));
+    }
+
+    public static void write(RegistryFriendlyByteBuf buffer, List<SymbolDisplayMetadata> entries) {
+        if (entries.size() > MAX_ENTRIES) throw new IllegalArgumentException("Desk symbol catalog exceeds limit");
+        buffer.writeVarInt(entries.size());
+        entries.forEach(entry -> SymbolDisplayMetadata.STREAM_CODEC.encode(buffer, entry));
+    }
+
+    public static List<SymbolDisplayMetadata> read(RegistryFriendlyByteBuf buffer) {
+        int count = buffer.readVarInt();
+        if (count < 0 || count > MAX_ENTRIES) throw new IllegalArgumentException("Invalid desk symbol count " + count);
+        List<SymbolDisplayMetadata> entries = new ArrayList<>(count);
+        for (int index = 0; index < count; index++) {
+            entries.add(SymbolDisplayMetadata.STREAM_CODEC.decode(buffer));
+        }
+        return List.copyOf(entries);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/WritingEntry.java

@@ -0,0 +1,82 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import java.util.Locale;
+import java.util.Objects;
+import java.util.Optional;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** One ordered unit of book writing. Interpretation belongs to Milestone 5. */
+public record WritingEntry(Kind kind, Optional<SymbolReference> symbol) {
+    private static final Codec<Kind> KIND_CODEC = Codec.STRING.comapFlatMap(
+            value -> {
+                try {
+                    return DataResult.success(Kind.valueOf(value.toUpperCase(Locale.ROOT)));
+                } catch (IllegalArgumentException exception) {
+                    return DataResult.error(() -> "Unknown writing entry kind: " + value);
+                }
+            },
+            value -> value.name().toLowerCase(Locale.ROOT)
+    );
+    private static final Codec<WritingEntry> RECORD_CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            KIND_CODEC.fieldOf("kind").forGetter(WritingEntry::kind),
+            SymbolReference.CODEC.optionalFieldOf("symbol").forGetter(WritingEntry::symbol)
+    ).apply(instance, WritingEntry::new));
+    public static final Codec<WritingEntry> CODEC = RECORD_CODEC.flatXmap(
+            WritingEntry::validate, WritingEntry::validate);
+    public static final StreamCodec<ByteBuf, WritingEntry> STREAM_CODEC = StreamCodec.of(
+            WritingEntry::encode, WritingEntry::decode);
+
+    public WritingEntry {
+        Objects.requireNonNull(kind, "kind");
+        symbol = Objects.requireNonNull(symbol, "symbol");
+        if (kind == Kind.SYMBOL && symbol.isEmpty()) {
+            throw new IllegalArgumentException("Symbol writing entries require a symbol reference");
+        }
+        if (kind == Kind.LINK_PANEL && symbol.isPresent()) {
+            throw new IllegalArgumentException("Link-panel writing entries cannot contain a symbol reference");
+        }
+    }
+
+    public static WritingEntry symbol(SymbolReference symbol) {
+        return new WritingEntry(Kind.SYMBOL, Optional.of(symbol));
+    }
+
+    public static WritingEntry linkPanel() {
+        return new WritingEntry(Kind.LINK_PANEL, Optional.empty());
+    }
+
+    private static DataResult<WritingEntry> validate(WritingEntry entry) {
+        return entry.kind == Kind.SYMBOL && entry.symbol.isEmpty()
+                || entry.kind == Kind.LINK_PANEL && entry.symbol.isPresent()
+                ? DataResult.error(() -> "Writing entry contents do not match kind " + entry.kind)
+                : DataResult.success(entry);
+    }
+
+    private static void encode(ByteBuf buffer, WritingEntry entry) {
+        ByteBufCodecs.VAR_INT.encode(buffer, entry.kind.ordinal());
+        if (entry.kind == Kind.SYMBOL) {
+            SymbolReference.STREAM_CODEC.encode(buffer, entry.symbol.orElseThrow());
+        }
+    }
+
+    private static WritingEntry decode(ByteBuf buffer) {
+        int ordinal = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (ordinal < 0 || ordinal >= Kind.values().length) {
+            throw new IllegalArgumentException("Unknown writing entry kind ordinal " + ordinal);
+        }
+        Kind kind = Kind.values()[ordinal];
+        return kind == Kind.SYMBOL
+                ? symbol(SymbolReference.STREAM_CODEC.decode(buffer))
+                : linkPanel();
+    }
+
+    public enum Kind {
+        SYMBOL,
+        LINK_PANEL
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/WritingInkService.java

@@ -0,0 +1,77 @@
+package net.dnorberg.rivencraft.writing;
+
+import net.dnorberg.rivencraft.config.RivencraftConfig;
+import net.dnorberg.rivencraft.item.InkVialItem;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+/** Server-owned costs and the baseline blank-page-to-link-panel transaction. */
+public final class WritingInkService {
+    private WritingInkService() {
+    }
+
+    public static int symbolCopyCost() {
+        return RivencraftConfig.symbolInkCost();
+    }
+
+    public static int linkPanelCost() {
+        return RivencraftConfig.linkPanelInkCost();
+    }
+
+    public static boolean canPrepareLinkPanel(Player player, InteractionHand vialHand) {
+        ItemStack vial = player.getItemInHand(vialHand);
+        ItemStack page = player.getItemInHand(other(vialHand));
+        int remaining = InkVialItem.remaining(vial);
+        return vial.is(ModItems.INK_VIAL.get()) && remaining >= linkPanelCost()
+                && remaining <= InkVialItem.CAPACITY
+                && page.is(Items.PAPER);
+    }
+
+    public static boolean prepareLinkPanel(Player player, InteractionHand vialHand) {
+        if (player.level().isClientSide || !canPrepareLinkPanel(player, vialHand)) {
+            return false;
+        }
+
+        InteractionHand pageHand = other(vialHand);
+        ItemStack page = player.getItemInHand(pageHand);
+        ItemStack vial = player.getItemInHand(vialHand);
+        int newInk = InkVialItem.remaining(vial) - linkPanelCost();
+        ItemStack panel = PageItem.createLinkPanelPage();
+        ItemStack spentVial = newInk == 0
+                ? new ItemStack(Items.GLASS_BOTTLE)
+                : new ItemStack(ModItems.INK_VIAL.get());
+        if (newInk > 0) {
+            spentVial.set(ModDataComponents.INK_REMAINING.get(), newInk);
+        }
+
+        // All validation and output construction is complete before changing either input.
+        if (page.getCount() == 1) {
+            player.setItemInHand(pageHand, panel);
+        } else {
+            page.shrink(1);
+            giveOrDrop(player, panel);
+        }
+        if (vial.getCount() == 1) {
+            player.setItemInHand(vialHand, spentVial);
+        } else {
+            vial.shrink(1);
+            giveOrDrop(player, spentVial);
+        }
+        return true;
+    }
+
+    private static InteractionHand other(InteractionHand hand) {
+        return hand == InteractionHand.MAIN_HAND ? InteractionHand.OFF_HAND : InteractionHand.MAIN_HAND;
+    }
+
+    private static void giveOrDrop(Player player, ItemStack stack) {
+        if (!player.getInventory().add(stack)) {
+            player.drop(stack, false);
+        }
+    }
+}

src/main/resources/assets/rivencraft/blockstates/writing_desk.json

@@ -0,0 +1,12 @@
+{
+  "variants": {
+    "facing=north,extension=false": {"model":"rivencraft:block/writing_desk"},
+    "facing=east,extension=false": {"model":"rivencraft:block/writing_desk","y":90},
+    "facing=south,extension=false": {"model":"rivencraft:block/writing_desk","y":180},
+    "facing=west,extension=false": {"model":"rivencraft:block/writing_desk","y":270},
+    "facing=north,extension=true": {"model":"rivencraft:block/writing_desk_extension"},
+    "facing=east,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":90},
+    "facing=south,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":180},
+    "facing=west,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":270}
+  }
+}

src/main/resources/assets/rivencraft/lang/en_us.json

@@ -6,6 +6,26 @@
   "item.rivencraft.linking_book.unbound": "Unbound — sneak-use to bind",
   "item.rivencraft.linking_book.destination": "%s (%s, %s, %s)",
   "item.rivencraft.linking_book.return": "Return Link",
+  "item.rivencraft.page": "Page",
+  "item.rivencraft.page.blank": "Blank Page",
+  "item.rivencraft.page.blank.description": "Ready for writing at a Writing Desk.",
+  "item.rivencraft.page.link_panel": "Link Panel Page",
+  "item.rivencraft.page.link_panel.description": "The baseline panel required to assemble a Descriptive Book.",
+  "item.rivencraft.page.unresolved": "Unresolved Symbol Page",
+  "item.rivencraft.notebook": "Notebook",
+  "item.rivencraft.notebook.pages": "Pages: %s/%s",
+  "item.rivencraft.notebook.unresolved": "Unresolved pages: %s",
+  "item.rivencraft.ink_vial": "Ink Vial",
+  "block.rivencraft.writing_desk": "Writing Desk",
+  "container.rivencraft.writing_desk": "Writing Desk",
+  "screen.rivencraft.writing_desk.ink": "Ink: %s/%s",
+  "screen.rivencraft.writing_desk.search": "Search",
+  "screen.rivencraft.writing_desk.no_symbols": "No available symbols",
+  "item.rivencraft.ink_vial.remaining": "Ink: %s/%s",
+  "item.rivencraft.ink_vial.usage": "Use with paper in the other hand to prepare a Link Panel.",
+  "screen.rivencraft.notebook.search": "Search pages",
+  "screen.rivencraft.notebook.move_previous": "Move selected page left",
+  "screen.rivencraft.notebook.move_next": "Move selected page right",
   "message.rivencraft.linking_book.bind_hint": "Sneak-use to bind this book to your current location",
   "message.rivencraft.linking_book.unbound": "This Linking Book is unbound",
   "message.rivencraft.linking_book.bound": "Linking Book bound as %s",
@@ -57,6 +77,20 @@
   "trait.rivencraft.weather.snow": "Snow",
   "trait.rivencraft.weather.storm": "Storm",
   "trait.rivencraft.day_length.stopped": "Stopped",
+  "symbol.rivencraft.unresolved": "Unresolved Symbol",
+  "symbol.rivencraft.unresolved.description": "Missing symbol: %s",
+  "symbol.rivencraft.terrain.standard": "Standard Terrain",
+  "symbol.rivencraft.terrain.standard.description": "A familiar continental terrain foundation.",
+  "symbol.rivencraft.biome.native": "Native Biomes",
+  "symbol.rivencraft.biome.native.description": "Use the terrain profile's native biome climate.",
+  "symbol.rivencraft.lighting.normal": "Normal Lighting",
+  "symbol.rivencraft.lighting.normal.description": "Use normal skylight and ambient brightness.",
+  "symbol.rivencraft.weather.normal": "Normal Weather",
+  "symbol.rivencraft.weather.normal.description": "Use the normal weather cycle.",
+  "symbol.rivencraft.celestial.normal_time": "Normal Time",
+  "symbol.rivencraft.celestial.normal_time.description": "Use a normal-length celestial cycle.",
+  "symbol.rivencraft.feature.caves": "Caves",
+  "symbol.rivencraft.feature.caves.description": "Describe underground cave features.",
   "generator.rivencraft.standard": "Standard",
   "generator.rivencraft.amplified": "Amplified",
   "generator.rivencraft.island": "Island",
@@ -69,5 +103,6 @@
   "screen.rivencraft.book.explore": "Explore",
   "screen.rivencraft.book.exploring": "Exploring",
   "screen.rivencraft.book.return_from_explore": "Right-click to return",
-  "itemGroup.rivencraft": "Rivencraft"
+  "itemGroup.rivencraft": "Rivencraft",
+  "itemGroup.rivencraft.pages": "Rivencraft Pages"
 }

src/main/resources/assets/rivencraft/models/block/writing_desk.json

@@ -0,0 +1,62 @@
+{
+	"format_version": "26.3",
+	"credit": "Made with Blockbench",
+	"parent": "minecraft:block/block",
+	"textures": {
+		"2": "rivencraft:block/writing_desk",
+		"particle": "rivencraft:block/writing_desk"
+	},
+	"elements": [
+		{
+			"from": [0, 11, 0],
+			"to": [16, 12, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 3, 0]},
+			"faces": {
+				"north": {"uv": [1, 2, 2, 2.125], "texture": "#2"},
+				"east": {"uv": [2.82031, 4.01563, 3.82031, 4.125], "texture": "#2"},
+				"south": {"uv": [0, 2, 1, 2.125], "texture": "#2"},
+				"west": {"uv": [2.9375, 0.125, 3, 2.125], "rotation": 90, "texture": "#2"},
+				"up": {"uv": [1, 0, 2, 2], "texture": "#2"},
+				"down": {"uv": [3, 0, 3.9375, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 1],
+			"to": [1, 11, 15],
+			"faces": {
+				"north": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
+				"east": {"uv": [7.6875, 2.625, 6.6875, 4], "texture": "#2"},
+				"south": {"uv": [1.42188, 10.78125, 2.4375, 11.85938], "texture": "#2"},
+				"west": {"uv": [5.67969, 2.625, 6.6875, 4], "texture": "#2"},
+				"up": {"uv": [0.08594, 10.36719, 1.14063, 11.83594], "texture": "#2"},
+				"down": {"uv": [5.75, 5.25, 5.8125, 7.10938], "texture": "#2"}
+			}
+		},
+		{
+			"from": [1, 5, 1],
+			"to": [16, 6, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 2, 0]},
+			"faces": {
+				"north": {"uv": [3, 2, 3.9375, 2.125], "texture": "#2"},
+				"east": {"uv": [2.8125, 4, 3.75, 4.125], "texture": "#2"},
+				"south": {"uv": [1.35938, 11.71875, 2.44531, 12.71875], "texture": "#2"},
+				"west": {"uv": [0.03125, 11.66406, 0.99219, 12.66406], "texture": "#2"},
+				"up": {"uv": [1.875, 4, 2.8125, 2.125], "texture": "#2"},
+				"down": {"uv": [0.9375, 2.125, 1.875, 4], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 15],
+			"to": [16, 11, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, -9, 0]},
+			"faces": {
+				"north": {"uv": [8.0625, 0, 9.0625, 1.375], "texture": "#2"},
+				"east": {"uv": [6.625, 0.125, 6.6875, 1.5], "texture": "#2"},
+				"south": {"uv": [5.625, 2.625, 6.625, 4], "texture": "#2"},
+				"west": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
+				"up": {"uv": [0, 15, 16, 16], "texture": "#2"},
+				"down": {"uv": [0, 9.17969, 16, 10.17969], "texture": "#2"}
+			}
+		}
+	]
+}

src/main/resources/assets/rivencraft/models/block/writing_desk_extension.json

@@ -0,0 +1,88 @@
+{
+	"format_version": "26.3",
+	"credit": "Made with Blockbench",
+	"parent": "minecraft:block/block",
+	"textures": {
+		"2": "rivencraft:block/writing_desk",
+		"particle": "rivencraft:block/writing_desk"
+	},
+	"elements": [
+		{
+			"from": [1, 0, 1],
+			"to": [15, 1, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [1, 0, 0]},
+			"faces": {
+				"north": {"uv": [1.8125, 4.125, 2.8125, 4.25], "texture": "#2"},
+				"east": {"uv": [0.21875, 11.88281, 1.04688, 12.88281], "texture": "#2"},
+				"south": {"uv": [1.53906, 10.5625, 2.63281, 11.5625], "texture": "#2"},
+				"west": {"uv": [0.14063, 10.5625, 1.17969, 11.5625], "texture": "#2"},
+				"up": {"uv": [1.8125, 4.125, 2.8125, 2.125], "texture": "#2"},
+				"down": {"uv": [4, 0, 5, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 11, 0],
+			"to": [16, 12, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 3, 0]},
+			"faces": {
+				"north": {"uv": [2, 2, 3, 2.125], "texture": "#2"},
+				"east": {"uv": [1, 0, 1.0625, 2], "rotation": 90, "texture": "#2"},
+				"south": {"uv": [3, 2, 4, 2.125], "texture": "#2"},
+				"west": {"uv": [2.8125, 4, 3.8125, 4.125], "texture": "#2"},
+				"up": {"uv": [2, 0, 3, 2], "texture": "#2"},
+				"down": {"uv": [9, 0, 10, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [15, 0, 1],
+			"to": [16, 11, 15],
+			"faces": {
+				"north": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
+				"east": {"uv": [10.00156, 0.625, 11.00156, 2], "texture": "#2"},
+				"south": {"uv": [1.99219, 10.77344, 2.99219, 12.02344], "texture": "#2"},
+				"west": {"uv": [6.6875, 2.625, 7.6875, 4], "texture": "#2"},
+				"up": {"uv": [0.49219, 10.96094, 1.49219, 12.08594], "texture": "#2"},
+				"down": {"uv": [5.75313, 5.36719, 5.8125, 7.125], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 1],
+			"to": [1, 11, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [-15, 0, 0]},
+			"faces": {
+				"north": {"uv": [7.68828, 2.625, 7.75078, 4], "texture": "#2"},
+				"east": {"uv": [7.6875, 2.62539, 6.6875, 4.00039], "texture": "#2"},
+				"south": {"uv": [0.05469, 12.22656, 1.05469, 13.32031], "texture": "#2"},
+				"west": {"uv": [3, 0, 4, 1.375], "texture": "#2"},
+				"up": {"uv": [0.15625, 10.83594, 1.15625, 11.97656], "texture": "#2"},
+				"down": {"uv": [7, 4.60156, 7.0625, 6.375], "texture": "#2"}
+			}
+		},
+		{
+			"from": [1, 5, 1],
+			"to": [15, 6, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [1, 2, 0]},
+			"faces": {
+				"north": {"uv": [1.8125, 4.25, 2.8125, 4.125], "texture": "#2"},
+				"east": {"uv": [1.86719, 11.82813, 2.79688, 12.82813], "texture": "#2"},
+				"south": {"uv": [0.32813, 11.80469, 1.28906, 12.80469], "texture": "#2"},
+				"west": {"uv": [0.27344, 10.5625, 1.53125, 11.5625], "texture": "#2"},
+				"up": {"uv": [1.8125, 4.125, 2.8125, 2.125], "texture": "#2"},
+				"down": {"uv": [9, 0, 10, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 15],
+			"to": [16, 11, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, -9, 0]},
+			"faces": {
+				"north": {"uv": [9, 0.125, 10, 1.5], "texture": "#2"},
+				"east": {"uv": [10.8125, 0.625, 10.875, 2], "texture": "#2"},
+				"south": {"uv": [10.875, 0.625, 11.875, 2], "texture": "#2"},
+				"west": {"uv": [6.6875, 0.125, 6.75, 1.5], "texture": "#2"},
+				"up": {"uv": [0, 15, 16, 16], "texture": "#2"},
+				"down": {"uv": [2.8125, 4, 3.8125, 4.125], "texture": "#2"}
+			}
+		}
+	]
+}

src/main/resources/assets/rivencraft/models/item/ink_vial.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/ink_vial"
+  }
+}

src/main/resources/assets/rivencraft/models/item/linking_book.json

@@ -1,6 +1,14 @@
 {
   "parent": "minecraft:item/generated",
   "textures": {
-    "layer0": "rivencraft:item/linking_book"
+    "layer0": "rivencraft:item/linking_book_unwritten"
-  }
+  },
+  "overrides": [
+    {
+      "predicate": {
+        "rivencraft:bound": 1.0
+      },
+      "model": "rivencraft:item/linking_book_bound"
+    }
+  ]
 }

src/main/resources/assets/rivencraft/models/item/linking_book_bound.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/linking_book"
+  }
+}

src/main/resources/assets/rivencraft/models/item/notebook.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/notebook"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page.json

@@ -0,0 +1,17 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page"
+  },
+  "overrides": [
+    { "predicate": { "custom_model_data": 1 }, "model": "rivencraft:item/page_link_panel" },
+    { "predicate": { "custom_model_data": 2 }, "model": "rivencraft:item/page_unresolved" },
+    { "predicate": { "custom_model_data": 3 }, "model": "rivencraft:item/page_symbol" },
+    { "predicate": { "custom_model_data": 100 }, "model": "rivencraft:item/page_symbol_terrain_standard" },
+    { "predicate": { "custom_model_data": 101 }, "model": "rivencraft:item/page_symbol_biome_native" },
+    { "predicate": { "custom_model_data": 102 }, "model": "rivencraft:item/page_symbol_lighting_normal" },
+    { "predicate": { "custom_model_data": 103 }, "model": "rivencraft:item/page_symbol_weather_normal" },
+    { "predicate": { "custom_model_data": 104 }, "model": "rivencraft:item/page_symbol_celestial_normal_time" },
+    { "predicate": { "custom_model_data": 105 }, "model": "rivencraft:item/page_symbol_feature_caves" }
+  ]
+}

src/main/resources/assets/rivencraft/models/item/page_link_panel.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_link_panel"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_symbol"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_biome_native.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_biome_native" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_celestial_normal_time.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_celestial_normal_time" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_feature_caves.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_feature_caves" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_lighting_normal.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_lighting_normal" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_terrain_standard.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_terrain_standard" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_weather_normal.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_weather_normal" }
+}

src/main/resources/assets/rivencraft/models/item/page_unresolved.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_unresolved"
+  }
+}

src/main/resources/assets/rivencraft/models/item/writing_desk.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {"layer0": "rivencraft:item/writing_desk"}
+}

src/main/resources/assets/rivencraft/textures/item/ink_vial.png.mcmeta

@@ -0,0 +1,3 @@
+{
+  "animation": {}
+}

src/main/resources/data/rivencraft/loot_table/blocks/writing_desk.json

@@ -0,0 +1,4 @@
+{
+  "type": "minecraft:block",
+  "pools": [{ "rolls": 1, "entries": [{ "type": "minecraft:item", "name": "rivencraft:writing_desk" }] }]
+}

src/main/resources/data/rivencraft/recipe/ink_vial.json

@@ -0,0 +1,14 @@
+{
+  "type": "minecraft:crafting_shapeless",
+  "category": "misc",
+  "ingredients": [
+    { "item": "minecraft:black_dye" },
+    { "item": "minecraft:black_dye" },
+    { "item": "minecraft:glass_bottle" },
+    { "item": "minecraft:water_bucket" }
+  ],
+  "result": {
+    "count": 1,
+    "id": "rivencraft:ink_vial"
+  }
+}

src/main/resources/data/rivencraft/recipe/notebook.json

@@ -0,0 +1,21 @@
+{
+  "type": "minecraft:crafting_shaped",
+  "category": "misc",
+  "key": {
+    "L": {
+      "item": "minecraft:leather"
+    },
+    "S": {
+      "item": "minecraft:string"
+    }
+  },
+  "pattern": [
+    " L ",
+    "S  ",
+    " L "
+  ],
+  "result": {
+    "count": 1,
+    "id": "rivencraft:notebook"
+  }
+}

src/main/resources/data/rivencraft/recipe/writing_desk.json

@@ -0,0 +1,11 @@
+{
+  "type": "minecraft:crafting_shaped",
+  "category": "misc",
+  "pattern": ["V F", "PPP", "P P"],
+  "key": {
+    "V": { "item": "minecraft:glass_bottle" },
+    "F": { "item": "minecraft:feather" },
+    "P": { "tag": "minecraft:planks" }
+  },
+  "result": { "id": "rivencraft:writing_desk", "count": 1 }
+}

src/main/resources/data/rivencraft/rivencraft/symbols/biome/native.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.biome.native",
+  "description": "symbol.rivencraft.biome.native.description",
+  "category": "rivencraft:biome"
+}