Port optional integrations and finish Age creation and modifier lifecycle

ports/mc263/README.md

@@ -11,9 +11,11 @@ bodies and eclipses, biome/material completion, and random features/structures.
 Crystal portals and libraries are ported. Instability scoring/provider selection,
 status effects, colored decay, lightning, explosions, meteors, burning and erosion,
 ordered writing recovery, live material profiling and all six Link Modifier controls are now ported.
-Link Modifier seed editing/retirement, remaining discovery/configuration and optional
-integrations remain unfinished. The latest published beta is
-[1.0.1.129-beta.1](RELEASE_NOTES_1.0.1.129-beta.1.md).
+Seed editing, operator-confirmed Age retirement and creation rollback are included.
+JEI, TerraBlender/Biomes O' Plenty, Serene Seasons/GlitchCore and Ruins are optional
+integrations. Live previews, remaining discovery/configuration parity and the final
+multiplayer regression remain unfinished. The latest published beta is
+[1.0.1.136-beta.1](RELEASE_NOTES_1.0.1.136-beta.1.md).
 Use a test world and keep a backup; do not
 substitute this JAR for the 1.21.1 mod or import 1.21.1 saves.
 
@@ -2531,3 +2533,271 @@ new server run was performed; the previous 19 checks covered server actions, not
 client input. Please click each option with an inserted Linking Book and verify
 its selected shading and tooltip/book properties change, then repeat supported
 options with a Descriptive Book. No commit, push or publication.
+
+
+## .130 Link Modifier seed editing
+
+Ported the 1.21.1 station's seed field into the Legacy GUI. It is visible for a
+bound Descriptive Book whose Age is still indexed, including an unloaded Age.
+The complete signed 64-bit seed synchronizes through four 16-bit menu data words;
+zero and negative seeds are not treated as missing data. Linking Books and unbound
+or retired references do not expose an editable seed.
+
+Enter/keypad Enter or clicking outside the field applies the edit; Escape closes
+without applying unfinished text. Focused typing consumes inventory/hotbar shortcuts.
+Modern InputConstants are used rather than legacy numeric key values. The bounded
+payload validates the open menu ID and expected Age ID, plus menu owner, station
+identity and distance. Invalid/overflowing input and occupied Ages are refused.
+This matches 1.21.1's ordinary creative-acquired station editing permissions.
+
+Successful edits use RuntimeAgeBackend.reseed, not a display-only book component.
+Existing chunks and book identity remain intact, while newly generated chunks use
+the changed seed. Existing backend unload/save/catalog synchronization is reused;
+frozen written choices and instability history are not rerolled. Retirement UI
+remains a later port slice.
+
+Version 1.0.1.130-beta.1 builds. A temporary dedicated-server fixture passed 16 menu/
+backend checks plus two restart checks: bound/unbound visibility, malformed/overflow
+input, stale expected Age, occupied and remote refusal, retained old terrain,
+changed index/level seed, unloaded reseeding including Long.MIN_VALUE, retained
+book identity and full restart persistence. Future-chunk height fingerprints from
+the menu-reseeded Age matched a fresh new-seed control and differed from an old-seed
+control (new=-1541880620; retained origin=924831745). The initial flat-world fixture
+could not distinguish terrain seeds; the terrain comparison used a normal-world
+fixture. All temporary test worlds and fixture sources were removed and the server
+stopped. The production JAR was rebuilt without fixtures. Client field input,
+feedback and real travel validation are delegated to the player. No commit, push
+or publication.
+
+
+## .131 Link Modifier Age retirement
+
+The player passed .130 seed editing. Ported the remaining 1.21.1 station retirement
+control through the existing 26.3 lifecycle backend. A bound, active Descriptive
+Book exposes the control only to players with modern Gamemaster (OP level 2)
+permission. The first native button arms retirement; a separate red confirmation
+button performs it. The arm and confirm actions have distinct IDs so repeating the
+initial click cannot silently confirm. Normal book editing permissions are unchanged.
+
+Confirmation is server-owned and tied to the exact Age and book components.
+Replacing/removing the book, renaming, changing properties or applying a seed edit
+clears confirmation; reopening the menu starts unarmed. Invalid, stale, non-OP and
+remote actions cannot retire an Age. The target must be empty of players, including
+the operator. A failed attempt clears confirmation and reports refusal.
+
+Successful retirement uses RuntimeAgeBackend.retire: flush/unload the target,
+persist its tombstone, archive only its directory beside the active world and
+synchronize the runtime catalog. Other Ages are retained. The inserted book keeps
+its now-dead identity, cannot reopen the retired Age, and no longer exposes seed or
+retirement controls. Storage failures reuse backend rollback and display failure.
+This follows 1.21.1 archival behavior rather than permanently erasing the files.
+
+Version 1.0.1.131-beta.1 builds. Eighteen temporary dedicated-server checks plus four
+restart checks passed: permission boundary, arm/confirm order, edits and book swaps,
+occupied/remote refusal, successful retirement, exact archive and surviving control
+Age, retained dead-book identity, repeated confirmation refusal, persisted tombstone,
+and refusal to reload/recreate after restart. Test servers were stopped and all
+worlds, archives and fixture sources removed. Production JAR rebuilt without the
+fixture. Client button visibility, tooltip/feedback, occupied refusal and travel
+through an old book are delegated to the player. No commit, push or publication.
+
+
+## .132 failed Age-creation rollback (#99)
+
+The player passed .131 retirement. Wrapped new runtime Age setup in one rollback
+boundary: library writing, level construction/load event, weather and Accelerated
+settings, index/initial display name, instability record and initial SavedData save.
+The catalog is published only after those steps succeed. Book creation now supplies
+its initial name to this operation and no longer configures acceleration/name after
+commit. Operator/default callers retain the prior overloads.
+
+A failed attempt closes the level stores, dispatches unload cleanup, removes its
+new index/environment entries without leaving a retirement tombstone, restores the
+prior library/instability metadata and saves that restoration. It removes only the
+exact, newly allocated Age directory with a non-following tree walk. Existing Age
+storage, live levels, retired IDs and unsafe/symlink paths are refused before any
+setup. Pre-existing directories are never reused or erased. Cleanup failures are
+attached to the original exception; if stores cannot close, files are retained to
+avoid racing an active writer. Book failures are logged/reported and do not move
+the caller. This covers recoverable runtime exceptions, not arbitrary process death
+or a guarantee against persistent filesystem/I/O failure.
+
+Index entry cleanup is shared with retirement without removing the retained display
+name needed by retirement rollback. No existing Age scores, generation or settings
+are migrated. No production fault-injection command/hook was introduced.
+
+Version 1.0.1.132-beta.1 builds. A temporary dedicated fixture passed 36 checks plus
+seven restart checks. Injected failures during LevelEvent.Load, instability creation
+and late display-name validation left no live/indexed Age, restored prior writing,
+dispatched one unload and removed only the new directory. Clean retries of the same
+IDs succeeded. An existing directory marker survived refusal. A failed book-creation
+call returned no Age and left its caller in the original world. Restart confirmed
+failed metadata stayed absent while committed names/Accelerated settings persisted.
+Fixture source, worlds and servers were removed/stopped; production JAR rebuilt
+without the fixture. Client validation: create two Ages with distinct names, travel
+and restart, including a book with Accelerated pages, and confirm their names,
+settings and destinations remain independent. No commit, push or publication.
+
+
+## .133 optional JEI integration (#102)
+
+The player passed .132. Adapted the 1.21.1 JEI plugin to the current 26.3 API and
+render extraction path. At the player's request, the target is the newest published
+26.3 NeoForge build, 31.17.0.109 (JEI labels it beta), verified against its official
+Maven metadata and Modrinth release API. This supersedes the initially inspected
+installed 31.17.0.94. The latest release channel differs from the latest published
+build; this slice deliberately targets the newer 31.17.0.109 build.
+
+Added searchable component-aware Symbol Pages, all eight mixer Link Panel variants
+and category/volume Symbol Portfolios. Registered biome and eligible Block/Fluid
+pages use the same pools as Creative, including installed registry content. Runtime
+registration fills any missing world-dependent variants; Blank Pages and the empty
+base portfolio are removed from JEI's ingredient list. Future pages entering the
+shared category pools participate automatically. Shared link-panel variant creation
+now supplies both Creative and JEI.
+
+Reused the Writing and Ink Mixer recipe-guide categories, additive chance guides,
+and Ink Vial/Writing Desk/Book Binder/Ink Mixer catalysts. The port-specific mixer
+text correctly states one paper plus one ink per panel, 16 units per vial and reset
+of additives on output pickup. Added Link Modifier information, without a recipe.
+Wrapped guide text uses opaque, shadow-free rendering and extra Mixer guide height.
+These are explanatory guides; no auto-transfer handler or fictitious Blank Page
+crafting recipe is introduced.
+
+JEI is compile-only and isolated in its annotated scanner plugin. It is not bundled
+or a required runtime dependency; no common class loads its plugin. The developer
+`-PwithJei` option adds JEI locally, including its Maven dependencies. The current
+109 POM requires MezzConfig 0.6.10 (and its GUI module); the existing test instance's
+0.6.9 must be updated alongside JEI as required by the mod's distribution metadata.
+Maven repository filters include JEI and MezzConfig groups only.
+
+Version 1.0.1.133-beta.1 builds against the 109 API. A fresh dedicated server started
+without JEI or any optional mods and stopped normally; its world was removed. Client
+plugin discovery, ingredient counts/subtype uniqueness, guide rendering and category
+navigation await the player's check with JEI 31.17.0.109 and its dependencies. Other
+optional integrations remain unported; #102 is not complete. No commit, push or
+publication, and no user's instance files were replaced.
+
+
+## .134 optional TerraBlender regions (#102)
+
+The player passed .133 JEI. Ported the 1.21.1 optional TerraBlender region adapter
+to the current 26.3 API, compile-only at 26.3.0.0.9 (the latest published 26.3
+build checked on Modrinth). The core boundary never exposes TerraBlender types.
+Absent/broken optional API falls back to existing tags/native pools, with one
+warning for API failures. No content mod is required or bundled. A developer
+`-PwithTerraBlender` runtime option is available.
+
+Enumerates registered non-vanilla biome keys from Overworld and Nether regions,
+excluding TerraBlender's deferred placeholder. Overworld additions extend random
+and seed-completed Standard/Amplified/Island/Flat pools. Nether-region membership
+extends Cave-compatible selection and Cave Page classification even without an
+is_nether tag. Registry-derived Creative and JEI page pools share that result.
+Runtime Age construction primes membership before biome validation/generation;
+Nether material-rule conditions also include recognized TerraBlender Nether keys.
+
+Region scans are cached per registry access with weak keys; hot generation queries
+use weak-holder membership rather than rescanning all regions. Tags updates refresh
+the relevant registry entry, and a lowest-priority server-about-to-start callback
+refreshes after TerraBlender loads data-driven regions. Frozen saved biome pools
+are not rerolled or migrated. No mod-specific biome names are hardcoded.
+
+Both 1.21.1 and 26.3 APIs expose OVERWORLD/NETHER, but no CAVE or END region type.
+This distinction and the need for cave tags/metadata were posted and verified in
+#111 (comment 605), including Nether precedence for overlapping Cave/Nether tags,
+explicit authoring, and the planned Native Nether/End pages. This slice retains
+current Native Cave eligibility: excluding Nether from its default pool and adding
+those new pages remain #111, for both version tracks. No 1.21.1 code was changed.
+
+Version 1.0.1.134-beta.1 builds. A clean dedicated server without TerraBlender
+starts normally. A fresh server with TerraBlender 26.3.0.0.9, BOP 26.3.0.0.16 and
+GlitchCore 26.3.0.0.5 passed nine focused checks: 59 Overworld additions, five Nether
+additions, placeholder exclusion, completion pools, Cave Page placement, an injected
+Nether region referencing an untagged biome, cache removal after region removal,
+and Cave Age acceptance/reload with a modded Nether biome. No bulk generation or
+client rendering was claimed. Test servers stopped, worlds and fixture sources
+removed; production JAR rebuilt without fixtures. Client Creative/JEI placement,
+actual BOP surface/Cave terrain materials and decoration remain player checks.
+No commit, push or publication. Other #102 integrations remain incomplete.
+
+
+## .135 optional Serene Seasons per-Age policies (#102)
+
+The player passed .134. Ported 1.21.1's six modes: No Seasons, cycling Seasons,
+Eternal Winter/Summer/Fall/Spring. Uses the latest published 26.3 Serene build
+26.1.2.0.7 (QnvW5HPm) and GlitchCore 26.3.0.0.5 (pQgy3bfh), matching the test
+instance. Both APIs are compile-only behind a guarded adapter, never bundled or
+required. The developer -PwithSereneSeasons flag adds them to the local runtime.
+
+New Ages freeze an authored or seed-selected policy in separate SavedData. Omitted
+choices randomize only when Serene is installed, matching root Legacy ranks:
+Seasons weight 6, No Seasons 5 and each Eternal 1. Cave terrain always disables
+seasons. Existing Ages without a stored policy retain legacy cycling behavior
+when integration/auto-whitelisting is enabled; they are not randomly reassigned.
+No Seasons is usable without the optional mod; other seasonal pages require it.
+Singular page recovery keeps the last seasonal controller with existing penalties.
+
+The guarded adapter writes only the target Age's whitelist entry and persists it
+through Serene/GlitchCore's config API. Connected-client updates and login replay
+apply the same entries without a restart. Existing unrelated entries are retained.
+Eternal policies hold the middle sub-season in a bounded mid-season window, avoiding
+per-tick dirty data and leaving the Overworld calendar unchanged. Server config
+serene_seasons.auto_whitelist_ages defaults true, matching 1.21.1: explicit policies
+still apply when disabled, while existing whitelist entries are not removed merely
+by disabling automatic behavior.
+
+Policy selection participates in creation rollback before catalog publication;
+optional whitelist changes happen only after successful creation. Reload/reseed
+reuse the frozen policy. Retirement removes its whitelist entry only after backend
+retirement succeeds, while policy history can remain in global metadata. Client
+messages are limited to Rivencraft Age IDs. Compatibility failures log once rather
+than flood every level tick. No Ecliptic Seasons support is added.
+
+Version 1.0.1.135-beta.1 builds. A clean dedicated server starts without optional
+mods. With Serene/GlitchCore, 25 checks passed on creation and 22 after full restart:
+all six saved modes/whitelist policies, each eternal mid-season and recovery from a
+changed cycle value, unchanged Overworld season data, unrelated whitelist entries,
+deterministic omitted choices, no random choice when the mod is absent, and Cave
+suppression. The initial restart assertion was corrected to allow the deliberate
+mid-season hold window inherited from 1.21.1. Test worlds/fixtures were removed and
+servers stopped; production JAR rebuilt without fixtures. Client visual effects,
+reconnect/live whitelist synchronization, normal season progression, authoring and
+retirement with a real connected client remain player validation. No commit, push
+or publication; other #102 integrations remain open.
+
+
+### Optional Ruins template pages — 1.0.1.136-beta.1
+
+The preceding Serene Seasons slice passed the player's in-game check. Ruins now
+uses the 1.21.1 exact-template bridge: each unambiguous installed `.tml` filename
+gets a dynamic glyph page in a Ruins creative tab, portfolios, and JEI's page pool.
+Names preserve case and Unicode through reversible IDs. Discovery reads Ruins'
+active `config/ruins_config` directory, with its bundled archive as the first-launch
+fallback. Duplicate basenames disable the bridge because Ruins' event cannot
+identify which directory supplied the template.
+
+Authored template choices and all duplicate counts are frozen in the Age's terrain
+feature plan and restored before its load event. Only selected templates pass the
+Age dimension and pre-spawn gates; other worlds retain Ruins' own behavior. Ruins'
+biome/surface/distance requirements remain applicable. Copies multiply template
+weight and increase attempts by one per extra page, capped at 32 attempts without
+lowering an explicitly higher Ruins configuration. The first three copies are free;
+each later copy adds 100 instability, including copies beyond the attempt cap.
+Material pages do not modify Ruins structures. Unloading clears bridge state and
+reloading restores it; optional Ruins classes are not loaded when the mod is absent.
+
+The reproducible compile-only baseline is Ruins 26.3.1NF (CurseForge file 8962119);
+the installed Ruins 26.3.2NF was used for integration validation. For development,
+`-PwithRuins` adds the baseline runtime, or combine it with
+`-PruinsJar=/absolute/path/to/ruins-26.3.2NF.jar` to run a local current build.
+Neither dependency is bundled or required to run Rivencraft.
+
+Build and clean dedicated-server startup without Ruins passed. With Ruins 26.3.2NF,
+21 checks passed on creation and 10 after restart, covering 25 discovered templates,
+creative/JEI pool parity, readable/case-sensitive IDs, authoring, codec roundtrip,
+50 retained copies, attempt limits, 4,700 excess-page instability, exact template
+filtering, both dimension gates, spawn-event veto, and a real Tiki Head placement
+(149 non-air blocks counted in the checked volume). Restart, unload, and reload
+retained the counts. Temporary fixtures and test worlds were removed; test servers
+were stopped. Client glyph/GUI checks and natural spawning while exploring an Age
+remain player validation. No commit, push, or publication; #102 remains open.

ports/mc263/RELEASE_NOTES_1.0.1.136-beta.1.md

@@ -0,0 +1,60 @@
+# Rivencraft 26.3 beta 1.0.1.136-beta.1
+
+Collects the player-validated .130–.136 port slices since 1.0.1.129-beta.1.
+For Minecraft 26.3, NeoForge 26.3.0.99 and Java 25. The Minecraft 1.21.1
+release and its Dynamic Dimensions backend are unchanged. This remains an
+incomplete beta port; use matching client/server builds and separate saves.
+
+## Link Modifier and Age creation
+
+- Edit a Descriptive Book Age's full signed 64-bit seed. Existing chunks remain;
+  newly generated terrain uses the new seed. Occupied Ages and stale/remote menu
+  requests are refused. Seed input supports Enter or focus loss without game keys
+  taking over while typing.
+- Operators can retire an unoccupied Age through a separate confirmation action.
+  Its exact dimension directory is archived under `world-retired-ages`; the Age
+  is tombstoned and cannot reload after restart. Other Age data remains intact.
+- Failed Age creation now rolls back the new level, index, initial name, library
+  writing, instability and season policy before publishing the catalog. Cleanup
+  removes only the newly created directory; pre-existing storage is protected.
+  Persistent filesystem failures or process crashes are not transactional guarantees.
+
+## Optional integrations
+
+All integrations remain optional and are never bundled.
+
+- **JEI:** searchable symbol pages, Link Panel variants and portfolios, with Ink
+  Mixer/Writing Desk/Book Binder guidance. Internal Blank Pages and empty portfolios
+  remain hidden. Tested with JEI 31.17.0.109 and MezzConfig 0.7.1.
+- **TerraBlender:** recognizes registered Overworld and Nether region biomes from
+  installed biome mods, including Biomes O' Plenty. Nether-region biomes join the
+  Cave-compatible authoring pool and use Nether material rules. Tested with
+  TerraBlender 26.3.0.0.9 and Biomes O' Plenty 26.3.0.0.16. The requested Native Cave
+  pool changes and Native Nether/End pages remain separate work in #111.
+- **Serene Seasons:** No Seasons, Seasons and all four Eternal modes operate per
+  Age. Missing policies are seed-selected only when Serene is installed; Cave Ages
+  disable seasons. Dynamic whitelist updates synchronize without restarting, while
+  eternal policies leave the Overworld calendar unchanged. Tested with Serene
+  Seasons 26.1.2.0.7 and GlitchCore 26.3.0.0.5.
+- **Ruins:** exact-template pages appear in creative and JEI. Authored Ages permit
+  only their selected templates; Ruins' surface, biome and distance checks remain.
+  Duplicate pages increase selection weight and attempts (32-attempt cap, without
+  lowering higher Ruins settings). The first three copies are free; each later
+  copy adds 100 instability, even beyond the attempt cap. Tested with Ruins
+  26.3.2NF. Duplicate template basenames disable the bridge to prevent ambiguity.
+
+## Validation and remaining work
+
+Both Minecraft builds pass. Every included slice passed player in-game checks;
+the latest client log confirms JEI, TerraBlender/BOP, Serene/GlitchCore and Ruins
+loaded together. Disposable dedicated-server checks covered seed changes with
+unchanged old chunks, retirement/archive isolation, injected creation failures,
+optional-mod absence, region discovery, season policies, Ruins template placement
+and restart/unload/reload persistence. Test fixtures/worlds were removed and test
+servers stopped. No permanent game tests were added.
+
+Books and crystal portals still use animated fallback previews. Live destination
+renderers, remaining discovery/configuration parity and random-Age glyph descriptions
+remain unfinished. The current expanded-catalog dedicated two-client regression
+and full parity/release gates remain open. Shared 1.21.1/26.3 follow-up issues are
+not complete merely because one version's implementation works.

ports/mc263/build.gradle

@@ -3,6 +3,39 @@ plugins {
     id 'net.neoforged.moddev' version '2.0.148'
 }
 
+repositories {
+    maven { url = 'https://www.cursemaven.com'; content { includeGroup 'curse.maven' } }
+    maven { url = 'https://api.modrinth.com/maven'; content { includeGroup 'maven.modrinth' } }
+    maven {
+        name = 'TerraBlenderMaven'
+        url = 'https://maven.minecraftforge.net/releases/'
+        content { includeGroup 'com.github.glitchfiend' }
+    }
+    maven {
+        name = 'JaredsMaven'
+        url = 'https://maven.blamejared.com'
+        content { includeGroup 'mezz.jei'; includeGroup 'net.mezzdev.config' }
+    }
+}
+dependencies {
+    // Compile against the 26.3 baseline API; a local current Ruins JAR can override it.
+    def ruinsDependency = project.hasProperty('ruinsJar') ? files(project.property('ruinsJar'))
+            : 'curse.maven:ruins-227873:8962119'
+    compileOnly ruinsDependency
+    if (project.hasProperty('withRuins')) localRuntime ruinsDependency
+    compileOnly "maven.modrinth:e0bNACJD:${serene_seasons_version_id}"
+    compileOnly "maven.modrinth:s3dmwKy5:${glitchcore_version_id}"
+    if (project.hasProperty('withSereneSeasons')) {
+        localRuntime "maven.modrinth:e0bNACJD:${serene_seasons_version_id}"
+        localRuntime "maven.modrinth:s3dmwKy5:${glitchcore_version_id}"
+    }
+    compileOnly "com.github.glitchfiend:TerraBlender-neoforge:${minecraft_version}-${terrablender_version}"
+    if (project.hasProperty('withTerraBlender')) localRuntime "com.github.glitchfiend:TerraBlender-neoforge:${minecraft_version}-${terrablender_version}"
+    // Plugin-only API dependency: JEI is never bundled or required at runtime.
+    compileOnly "mezz.jei:jei-${minecraft_version}-neoforge-api:${jei_version}"
+    if (project.hasProperty('withJei')) localRuntime "mezz.jei:jei-${minecraft_version}-neoforge:${jei_version}"
+}
+
 group = 'net.dnorberg.rivencraft'
 version = mod_version
 

ports/mc263/gradle.properties

@@ -7,4 +7,11 @@ neo_version=26.3.0.99
 mod_id=rivencraft
 mod_name=Rivencraft
 mod_license=LGPL-3.0-or-later
-mod_version=1.0.1.129-beta.1
+mod_version=1.0.1.136-beta.1
+
+jei_version=31.17.0.109
+
+terrablender_version=26.3.0.0.9
+
+serene_seasons_version_id=QnvW5HPm
+glitchcore_version_id=pQgy3bfh

ports/mc263/port_en_us.json

@@ -106,5 +106,9 @@
   "symbol.rivencraft.feature.ruined_portals.description": "Allow ruined portals in noise terrain, including Cave, regardless of normal biome eligibility.",
   "symbol.rivencraft.feature.nether_fossils.description": "Allow Nether fossils in Cave terrain; the authored page overrides biome eligibility.",
   "symbol.rivencraft.feature.ancient_cities.description": "Allow underground Ancient Cities in noise terrain, including Cave, regardless of biome eligibility.",
-  "symbol.rivencraft.feature.trail_ruins.description": "Allow Trail Ruins in surface noise terrain, including outside their usual biomes."
+  "symbol.rivencraft.feature.trail_ruins.description": "Allow Trail Ruins in surface noise terrain, including outside their usual biomes.",
+  "jei.rivencraft.ink_mixer.usage": "Paper + ink makes a Link Panel. Each panel uses one paper and one ink. A vial supplies 16 ink and returns a glass bottle; additives reset when a panel is taken.",
+  "jei.rivencraft.link_modifier": "Creative-only tool; no crafting recipe. Insert a book to rename it and edit link properties. Bound Descriptive Books also allow seed editing while their Age is empty. Age retirement requires OP permission and a separate confirmation; its data is archived.",
+  "symbol.rivencraft.ruins.description": "Generates this Ruins template. Repeated pages increase its selection weight and spawn attempts.",
+  "itemGroup.rivencraft.pages.ruins": "Rivencraft Ruins Pages"
 }

ports/mc263/src/main/java/net/dnorberg/rivencraft/PortConfig.java

@@ -8,6 +8,7 @@ public final class PortConfig {
     public static final ModConfigSpec.EnumValue<LibraryLootMode> LIBRARY_LOOT_MODE;
     public enum ReturnLinkMode { ON_CREATION, ALWAYS, DISABLED }
     public static final ModConfigSpec SPEC;
+    public static final ModConfigSpec.BooleanValue AUTO_WHITELIST_SERENE_AGES;
     public static final ModConfigSpec.IntValue SYMBOL_INK_COST;
     public static final ModConfigSpec.IntValue LINK_PANEL_INK_COST;
     public static final ModConfigSpec.EnumValue<ReturnLinkMode> RETURN_LINK_MODE;
@@ -16,6 +17,10 @@ public final class PortConfig {
 
     static {
         var builder = new ModConfigSpec.Builder();
+        builder.push("serene_seasons");
+        AUTO_WHITELIST_SERENE_AGES = builder.comment("Automatically whitelist Ages with seed-selected/legacy cycling seasons. Explicit pages still apply; existing entries are preserved when disabled.")
+                .define("auto_whitelist_ages", true);
+        builder.pop();
         builder.push("descriptive_books");
         RETURN_LINK_MODE = builder.comment("Controls automatic Return Links for successful Descriptive Book travel.",
                 "ON_CREATION issues one on the first arrival per Age/world; ALWAYS issues one each arrival; DISABLED issues none.")

ports/mc263/src/main/java/net/dnorberg/rivencraft/Rivencraft.java

@@ -248,6 +248,7 @@ public final class Rivencraft {
         MENUS.register(modEventBus);
         COMPONENTS.register(modEventBus);
         RECIPE_SERIALIZERS.register(modEventBus);
+        net.dnorberg.rivencraft.compat.RuinsCompatibility.register();
         ModCreativeTabs.register(modEventBus);
         PortBiomeSources.register(modEventBus);
         PortChunkGenerators.register(modEventBus);
@@ -255,8 +256,14 @@ public final class Rivencraft {
         NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.age.PortAgeWeather::onLevelTickPre);
         NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.age.PortAcceleratedTicks::onLevelTickPost);
         NeoForge.EVENT_BUS.addListener(PortAgeCommands::register);
+        NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.compat.TerraBlenderBiomes::onTagsUpdated);
+        NeoForge.EVENT_BUS.addListener(net.neoforged.bus.api.EventPriority.LOWEST,
+                net.dnorberg.rivencraft.compat.TerraBlenderBiomes::onServerAboutToStart);
         NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.event.BookStandConversionHandler::onRightClickBlock);
         NeoForge.EVENT_BUS.addListener(AgeCatalogSync::onLogin);
+        NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility::onLevelLoad);
+        NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility::onLogin);
+        NeoForge.EVENT_BUS.addListener(net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility::onLevelTickPost);
         NeoForge.EVENT_BUS.addListener(AgeCatalogSync::onLogout);
         NeoForge.EVENT_BUS.addListener(AgeCatalogSync::onServerStopped);
         modEventBus.addListener(AgeCatalogSync::registerPayloads);

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/AgeLevelIndex.java

@@ -182,8 +182,15 @@ final class AgeLevelIndex extends SavedData {
         setDirty();
     }
 
-    void retire(Identifier id) {
-        if (ages.remove(id) == null) throw new IllegalArgumentException("Age not indexed: " + id);
+    /** Failed creation is not retirement: release the new identity for a clean retry. */
+    void discardCreation(Identifier id) {
+        if (retired.contains(id)) throw new IllegalArgumentException("Cannot discard a retired Age: " + id);
+        removeActive(id);
+        displayNames.remove(id);
+        setDirty();
+    }
+    private void removeActive(Identifier id) {
+        ages.remove(id);
         biomeOverrides.remove(id);
         biomePlans.remove(id);
         terrain.remove(id);
@@ -196,6 +203,10 @@ final class AgeLevelIndex extends SavedData {
         sky.remove(id);
         colors.remove(id);
         dayCycles.remove(id);
+    }
+    void retire(Identifier id) {
+        if (!ages.containsKey(id)) throw new IllegalArgumentException("Age not indexed: " + id);
+        removeActive(id);
         retired.add(id);
         setDirty();
     }

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortAgeLevel.java

@@ -51,6 +51,8 @@ final class PortAgeLevel extends ServerLevel {
         return ageWeather == null ? super.getWeatherData() : ageWeather;
     }
 
+    boolean caveTerrain() { return cave; }
+
     PortWeatherMode weatherMode() { return cave ? PortWeatherMode.OFF : weatherSettings.mode(); }
 
     void configureWeather(PortWeatherMode mode) {

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortBiomeMaterialRules.java

@@ -16,12 +16,18 @@ final class PortBiomeMaterialRules {
     static Holder<NoiseGeneratorSettings> apply(HolderLookup.Provider registries, NoiseGeneratorSettings base) {
         var biomes = registries.lookupOrThrow(Registries.BIOME);
         var rules = registries.lookupOrThrow(Registries.MATERIAL_RULE);
+        var nether = java.util.stream.Stream.concat(java.util.stream.Stream.of(Biomes.NETHER_WASTES,
+                        Biomes.SOUL_SAND_VALLEY, Biomes.CRIMSON_FOREST, Biomes.WARPED_FOREST, Biomes.BASALT_DELTAS),
+                net.dnorberg.rivencraft.compat.TerraBlenderBiomes.nether(registries).stream()
+                        .map(id -> net.minecraft.resources.ResourceKey.create(Registries.BIOME, id)))
+                .distinct().toList();
+        @SuppressWarnings("unchecked")
+        net.minecraft.resources.ResourceKey<net.minecraft.world.level.biome.Biome>[] netherKeys = nether.toArray(net.minecraft.resources.ResourceKey[]::new);
         var materials = MaterialRules.sequence(
                 MaterialRules.ifTrue(MaterialRules.isBiome(biomes, Biomes.THE_END, Biomes.END_HIGHLANDS,
                         Biomes.END_MIDLANDS, Biomes.SMALL_END_ISLANDS, Biomes.END_BARRENS),
                         MaterialRules.getRule(rules, EndMaterialRules.END)),
-                MaterialRules.ifTrue(MaterialRules.isBiome(biomes, Biomes.NETHER_WASTES, Biomes.SOUL_SAND_VALLEY,
-                        Biomes.CRIMSON_FOREST, Biomes.WARPED_FOREST, Biomes.BASALT_DELTAS),
+                MaterialRules.ifTrue(MaterialRules.isBiome(biomes, netherKeys),
                         MaterialRules.getRule(rules, NetherMaterialRules.NETHER)),
                 base.materialRule().value());
         return Holder.direct(new NoiseGeneratorSettings(base.noiseSettings(), base.defaultBlock(), base.defaultFluid(),

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortInstabilityData.java

@@ -42,6 +42,11 @@ public final class PortInstabilityData extends SavedData {
     private final Map<Identifier, Age> ages = new HashMap<>();
     private PortInstabilityData(Map<Identifier, Age> values) { ages.putAll(values); }
     public static PortInstabilityData get(MinecraftServer server) { return server.overworld().getDataStorage().computeIfAbsent(TYPE); }
+    Age snapshot(Identifier id) { return ages.get(id); }
+    void restore(Identifier id, Age snapshot) {
+        if (snapshot == null) ages.remove(id); else ages.put(id, snapshot);
+        setDirty();
+    }
     public Age age(ServerLevel level) {
         Age age = ages.get(level.dimension().identifier());
         return age != null ? age : new Age(level.getSeed(),
@@ -90,6 +95,10 @@ public final class PortInstabilityData extends SavedData {
                     || PortDayCycle.isController(page) || PortDayCycle.isPeriod(page)
                     || PortDayCycle.isPhase(page) || PortDayCycle.isAngle(page) || PortDayCycle.isDirection(page)))
                 costs.add(new Contribution("cave_ignored_" + path.replace('/', '_'), i, 100));
+            if (net.dnorberg.rivencraft.compat.RuinsTemplatePages.isSymbol(page)) {
+                if (structures.merge(page, 1, Integer::sum) > 3)
+                    costs.add(new Contribution("excess_" + path, i, 100));
+            }
             if (PortStructurePages.supports(page)) {
                 int count = structures.merge(page, 1, Integer::sum);
                 if (count > 3) costs.add(new Contribution("excess_" + path, i, 100));

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortRandomAgeSelection.java

@@ -69,11 +69,16 @@ public final class PortRandomAgeSelection {
         }
         List<Identifier> surface = server.overworld().getChunkSource().getGenerator().getBiomeSource()
                 .possibleBiomes().stream().flatMap(holder -> holder.unwrapKey().stream())
-                .map(key -> key.identifier()).distinct().sorted(Comparator.naturalOrder()).toList();
+                .map(key -> key.identifier()).filter(id -> !id.equals(PortRegistryPages.DEFERRED_PLACEHOLDER))
+                .distinct().sorted(Comparator.naturalOrder()).toList();
+        surface = java.util.stream.Stream.concat(surface.stream(),
+                net.dnorberg.rivencraft.compat.TerraBlenderBiomes.overworld(server.registryAccess()).stream())
+                .distinct().sorted().toList();
         return surface.isEmpty() ? List.of(Identifier.withDefaultNamespace("plains")) : surface;
     }
 
     public static List<Identifier> caveBiomes(net.minecraft.core.HolderLookup.Provider registries) {
+        net.dnorberg.rivencraft.compat.TerraBlenderBiomes.nether(registries);
         var caves = registries.lookupOrThrow(Registries.BIOME).listElements()
                 .filter(PortRegistryPages::isCaveBiome).map(holder -> holder.key().identifier()).sorted().toList();
         return caves.isEmpty() ? List.of(Identifier.withDefaultNamespace("lush_caves")) : caves;

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortRandomFeatureSelection.java

@@ -19,7 +19,7 @@ public final class PortRandomFeatureSelection {
         var plan = base.terrain();
         plan = plan == null ? new PortTerrainFeaturePlan(List.of(), false, 0, false, structures.structures(), List.of(), true)
                     : new PortTerrainFeaturePlan(plan.choices(), plan.skylands(), plan.denseOres(), plan.starFissures(),
-                            structures.structures(), plan.carvers(), true);
+                            structures.structures(), plan.carvers(), true, plan.ruins());
         return new Selection(base.rocks(), base.lakes(), plan, structures.dungeons());
     }
 

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortSeasonPolicies.java

@@ -0,0 +1,57 @@
+package net.dnorberg.rivencraft.age;
+
+import java.util.*;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.level.saveddata.SavedData;
+import net.minecraft.world.level.saveddata.SavedDataType;
+
+/** Frozen per-Age season choice, separate from the backend's legacy index codec. */
+public final class PortSeasonPolicies extends SavedData {
+    public enum Mode {
+        NO_SEASONS, SEASONS, ETERNAL_WINTER, ETERNAL_SUMMER, ETERNAL_FALL, ETERNAL_SPRING;
+        public boolean eternal() { return this != NO_SEASONS && this != SEASONS; }
+    }
+    public record Policy(Mode mode, boolean authored) {
+        static final Codec<Policy> CODEC = RecordCodecBuilder.create(i -> i.group(
+                Codec.STRING.xmap(Mode::valueOf, Mode::name).fieldOf("mode").forGetter(Policy::mode),
+                Codec.BOOL.fieldOf("authored").forGetter(Policy::authored)).apply(i, Policy::new));
+    }
+    private static final SavedDataType<PortSeasonPolicies> TYPE = new SavedDataType<>(
+            Identifier.fromNamespaceAndPath("rivencraft", "season_policies"), () -> new PortSeasonPolicies(Map.of()),
+            Codec.unboundedMap(Identifier.CODEC, Policy.CODEC).fieldOf("ages").codec()
+                    .xmap(PortSeasonPolicies::new, data -> Map.copyOf(data.policies)));
+    private final Map<Identifier, Policy> policies = new HashMap<>();
+    private PortSeasonPolicies(Map<Identifier, Policy> values) { policies.putAll(values); }
+    public static PortSeasonPolicies get(MinecraftServer server) { return server.overworld().getDataStorage().computeIfAbsent(TYPE); }
+    Policy snapshot(Identifier id) { return policies.get(id); }
+    void put(Identifier id, Policy policy) { if (policy == null) policies.remove(id); else policies.put(id, policy); setDirty(); }
+    public Policy forLevel(ServerLevel level) {
+        if (level instanceof PortAgeLevel age && age.caveTerrain()) return new Policy(Mode.NO_SEASONS, true);
+        // Existing Ages retain cycling behavior when integration is installed later.
+        return policies.getOrDefault(level.dimension().identifier(), new Policy(Mode.SEASONS, false));
+    }
+    public static Mode forPage(Identifier id) {
+        if (!id.getNamespace().equals("rivencraft") || !id.getPath().startsWith("season/")) return null;
+        try { return Mode.valueOf(id.getPath().substring(7).toUpperCase(Locale.ROOT)); }
+        catch (IllegalArgumentException e) { return null; }
+    }
+    static Policy select(List<Identifier> pages, long seed, PortAgeTerrain terrain, boolean installed) {
+        if (terrain == PortAgeTerrain.CAVE) return new Policy(Mode.NO_SEASONS, true);
+        Mode written = null;
+        for (var page : pages) if (forPage(page) != null) written = forPage(page);
+        if (written != null) {
+            if (!installed && written != Mode.NO_SEASONS) throw new IllegalArgumentException("Seasonal pages require Serene Seasons");
+            return new Policy(written, true);
+        }
+        if (!installed) return null;
+        // 1.21.1 LegacyRankChoice ranks: Seasons=1, None=2, each Eternal=3.
+        int ticket = new Random(seed ^ 0x5E450A5E5EED21L).nextInt(15);
+        Mode mode = ticket < 6 ? Mode.SEASONS : ticket < 11 ? Mode.NO_SEASONS
+                : List.of(Mode.ETERNAL_WINTER, Mode.ETERNAL_SUMMER, Mode.ETERNAL_FALL, Mode.ETERNAL_SPRING).get(ticket - 11);
+        return new Policy(mode, false);
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/PortTerrainFeaturePlan.java

@@ -10,7 +10,7 @@ import net.minecraft.resources.Identifier;
 /** Frozen terrain filters and ordered solid/surface features for an Age. */
 public record PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int denseOres,
                                      boolean starFissures, List<Identifier> structures, List<Identifier> carvers,
-                                     boolean structureControl) {
+                                     boolean structureControl, List<Identifier> ruins) {
     public static final Identifier FLOATING_ISLANDS = Identifier.fromNamespaceAndPath(
             Rivencraft.MOD_ID, "feature/floating_islands");
     public static final Identifier TENDRILS = Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "feature/tendrils");
@@ -32,7 +32,8 @@ public record PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int
             Codec.BOOL.optionalFieldOf("star_fissures", false).forGetter(PortTerrainFeaturePlan::starFissures),
             Identifier.CODEC.listOf().optionalFieldOf("structures", List.of()).forGetter(PortTerrainFeaturePlan::structures),
             Identifier.CODEC.listOf().optionalFieldOf("carvers", List.of()).forGetter(PortTerrainFeaturePlan::carvers),
-            Codec.BOOL.optionalFieldOf("structure_control", false).forGetter(PortTerrainFeaturePlan::structureControl)
+            Codec.BOOL.optionalFieldOf("structure_control", false).forGetter(PortTerrainFeaturePlan::structureControl),
+            Identifier.CODEC.listOf().optionalFieldOf("ruins", List.of()).forGetter(PortTerrainFeaturePlan::ruins)
     ).apply(instance, PortTerrainFeaturePlan::new));
 
     public record Choice(Identifier page, Identifier material) {
@@ -50,6 +51,9 @@ public record PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int
     }
 
     public PortTerrainFeaturePlan {
+        ruins = List.copyOf(ruins);
+        if (ruins.size() > 252 || ruins.stream().anyMatch(id -> !net.dnorberg.rivencraft.compat.RuinsTemplatePages.isSymbol(id)))
+            throw new IllegalArgumentException("Invalid Ruins template pages");
         choices = List.copyOf(choices);
         structures = List.copyOf(structures);
         carvers = List.copyOf(carvers);
@@ -57,7 +61,7 @@ public record PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int
         PortCarverPages.validateCounts(carvers);
         if (denseOres < 0 || denseOres > MAX_PER_FEATURE)
             throw new IllegalArgumentException("Dense Ores permits at most 32 occurrences");
-        if (choices.isEmpty() && !skylands && denseOres == 0 && !starFissures && structures.isEmpty() && carvers.isEmpty() && !structureControl)
+        if (choices.isEmpty() && !skylands && denseOres == 0 && !starFissures && structures.isEmpty() && carvers.isEmpty() && !structureControl && ruins.isEmpty())
             throw new IllegalArgumentException("Terrain feature plan must not be empty");
         var counts = new HashMap<Identifier, Integer>();
         for (Choice choice : choices) {
@@ -66,6 +70,12 @@ public record PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int
         }
     }
 
+    public PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int denseOres,
+                                 boolean starFissures, List<Identifier> structures, List<Identifier> carvers,
+                                 boolean structureControl) {
+        this(choices, skylands, denseOres, starFissures, structures, carvers, structureControl, List.of());
+    }
+
     public PortTerrainFeaturePlan(List<Choice> choices, boolean skylands, int denseOres,
                                  boolean starFissures, List<Identifier> structures, List<Identifier> carvers) {
         this(choices, skylands, denseOres, starFissures, structures, carvers, false);

ports/mc263/src/main/java/net/dnorberg/rivencraft/age/RuntimeAgeBackend.java

@@ -159,24 +159,110 @@ public final class RuntimeAgeBackend {
                                      PortTerrainFeaturePlan terrainFeatures, PortWeatherMode weather,
                                      PortLighting lighting, PortSkyStyle sky, PortAgeColors colors, PortDayCycle dayCycle,
                                      List<Identifier> librarySymbols) {
+        return create(server, id, seed, biomePlan, terrain, rocks, vegetation, dungeons, lakes, terrainFeatures,
+                weather, lighting, sky, colors, dayCycle, librarySymbols, null);
+    }
+
+    public static ServerLevel create(MinecraftServer server, Identifier id, long seed,
+                                     PortBiomePlan biomePlan, PortAgeTerrain terrain, PortRockPlan rocks,
+                                     PortVegetationPlan vegetation, int dungeons, PortLakePlan lakes,
+                                     PortTerrainFeaturePlan terrainFeatures, PortWeatherMode weather,
+                                     PortLighting lighting, PortSkyStyle sky, PortAgeColors colors, PortDayCycle dayCycle,
+                                     List<Identifier> librarySymbols, String displayName) {
         checkServerThread(server);
-        ageName(id);
+        String name = ageName(id);
         AgeLevelIndex index = index(server);
-        if (index.contains(id)) throw new IllegalArgumentException("Age already exists: " + id);
-        PortLibraryWriting.get(server).put(id, librarySymbols);
-        ServerLevel level = load(server, id, seed, biomePlan, terrain, rocks, vegetation, dungeons, lakes,
-                terrainFeatures, lighting, sky, colors, dayCycle);
-        ((PortAgeLevel) level).configureWeather(weather);
-        index.add(id, seed, biomePlan, terrain, rocks, vegetation, dungeons, lakes, terrainFeatures, lighting, sky, colors, dayCycle);
-        PortInstabilityData.get(server).create(level, librarySymbols, terrain, lighting, dayCycle);
-        // A newly bound book may be used immediately. Persist its Age identity
-        // before publishing the catalog so a later crash cannot leave that
-        // book pointing at a world omitted from the on-disk index.
-        server.overworld().getDataStorage().saveAndJoin();
+        if (index.contains(id) || server.getLevel(dimensionKey(id)) != null)
+            throw new IllegalArgumentException("Age already exists: " + id);
+        Path directory = archivePaths(server, name).live();
+        if (Files.exists(directory, LinkOption.NOFOLLOW_LINKS))
+            throw new IllegalArgumentException("Age storage already exists: " + id);
+        PortLibraryWriting writing = PortLibraryWriting.get(server);
+        List<Identifier> priorWriting = writing.symbols(id);
+        PortInstabilityData instability = PortInstabilityData.get(server);
+        PortInstabilityData.Age priorInstability = instability.snapshot(id);
+        PortSeasonPolicies seasons = PortSeasonPolicies.get(server);
+        PortSeasonPolicies.Policy priorSeason = seasons.snapshot(id);
+        ServerLevel level = null;
+        try {
+            seasons.put(id, PortSeasonPolicies.select(librarySymbols, seed, terrain,
+                    net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility.available()));
+            writing.put(id, librarySymbols);
+            level = load(server, id, seed, biomePlan, terrain, rocks, vegetation, dungeons, lakes,
+                    terrainFeatures, lighting, sky, colors, dayCycle);
+            ((PortAgeLevel) level).configureWeather(weather);
+            int accelerated = PortAcceleratedTicks.pageCount(librarySymbols);
+            if (accelerated > 0) PortAcceleratedTicks.configure(level, accelerated);
+            index.add(id, seed, biomePlan, terrain, rocks, vegetation, dungeons, lakes, terrainFeatures, lighting, sky, colors, dayCycle);
+            instability.create(level, librarySymbols, terrain, lighting, dayCycle);
+            if (displayName != null) index.setDisplayName(id, displayName);
+            // Commit all initial metadata before announcing an enterable Age.
+            level.getDataStorage().saveAndJoin();
+            server.overworld().getDataStorage().saveAndJoin();
+        } catch (RuntimeException failure) {
+            boolean closed = !(failure instanceof FailedAgeCleanupException);
+            if (level != null) {
+                try { closeFailedCreation(server, level); }
+                catch (RuntimeException cleanup) { closed = false; failure.addSuppressed(cleanup); }
+            }
+            index.discardCreation(id);
+            writing.put(id, priorWriting);
+            instability.restore(id, priorInstability);
+            seasons.put(id, priorSeason);
+            try { server.overworld().getDataStorage().saveAndJoin(); }
+            catch (RuntimeException cleanup) { failure.addSuppressed(cleanup); }
+            // Only the exact, previously absent directory belongs to this attempt.
+            // If closing failed, leave its files in place rather than race a writer.
+            if (closed) {
+                try { removeFailedCreationDirectory(server, name, directory); }
+                catch (IOException | RuntimeException cleanup) { failure.addSuppressed(cleanup); }
+            }
+            throw failure;
+        }
+        net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility.apply(level);
         AgeCatalogSync.onCatalogChanged(server);
         return level;
     }
 
+    private static final class FailedAgeCleanupException extends IllegalStateException {
+        FailedAgeCleanupException(RuntimeException cause) { super("Failed Age stores could not close; files retained", cause); }
+    }
+
+    private static void closeFailedCreation(MinecraftServer server, ServerLevel level) {
+        if (!level.players().isEmpty()) throw new IllegalStateException("Failed Age contains players: " + level.dimension().identifier());
+        RuntimeException error = null;
+        try { level.getChunkSource().deactivateTicketsOnClosing(); }
+        catch (RuntimeException failure) { error = failure; }
+        try { level.close(); }
+        catch (IOException | RuntimeException failure) {
+            if (error == null) error = new IllegalStateException("Could not close failed Age", failure);
+            else error.addSuppressed(failure);
+        } finally {
+            server.levels.remove(level.dimension(), level);
+            try { NeoForge.EVENT_BUS.post(new LevelEvent.Unload(level)); }
+            catch (RuntimeException failure) {
+                if (error == null) error = failure; else error.addSuppressed(failure);
+            }
+        }
+        if (error != null) throw error;
+    }
+
+    private static void removeFailedCreationDirectory(MinecraftServer server, String name, Path directory) throws IOException {
+        if (!archivePaths(server, name).live().equals(directory)) throw new IOException("Age directory changed during rollback");
+        if (!Files.exists(directory, LinkOption.NOFOLLOW_LINKS)) return;
+        Files.walkFileTree(directory, new java.nio.file.SimpleFileVisitor<Path>() {
+            @Override public java.nio.file.FileVisitResult visitFile(Path file, java.nio.file.attribute.BasicFileAttributes attributes) throws IOException {
+                Files.delete(file);
+                return java.nio.file.FileVisitResult.CONTINUE;
+            }
+            @Override public java.nio.file.FileVisitResult postVisitDirectory(Path dir, IOException error) throws IOException {
+                if (error != null) throw error;
+                Files.delete(dir);
+                return java.nio.file.FileVisitResult.CONTINUE;
+            }
+        });
+    }
+
     /** Unloads an Age only when no player remains; save(true) flushes other entities. */
     public static void unload(MinecraftServer server, Identifier id) {
         checkServerThread(server);
@@ -278,6 +364,7 @@ public final class RuntimeAgeBackend {
             }
             throw new IllegalStateException("Could not archive Age " + id, exception);
         }
+        net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility.retired(server, id);
         AgeCatalogSync.onCatalogChanged(server);
         Rivencraft.LOGGER.info("Retired 26.3 prototype Age {} (archived at {})", id, paths.archive());
     }
@@ -420,6 +507,7 @@ public final class RuntimeAgeBackend {
                                     PortVegetationPlan vegetation, int dungeons, PortLakePlan lakes,
                                     PortTerrainFeaturePlan terrainFeatures, PortLighting lighting, PortSkyStyle sky,
                                     PortAgeColors colors, PortDayCycle dayCycle) {
+        net.dnorberg.rivencraft.compat.TerraBlenderBiomes.nether(server.registryAccess());
         ResourceKey<Level> key = ResourceKey.create(Registries.DIMENSION, id);
         if (server.getLevel(key) != null) throw new IllegalArgumentException("Level already loaded: " + id);
         if (biomePlan != null && biomePlan.distribution() == PortBiomePlan.Distribution.NATIVE
@@ -506,6 +594,7 @@ public final class RuntimeAgeBackend {
         // Publish only after the constructor succeeds. If the load event fails,
         // roll back the map and close the newly opened chunk/entity stores.
         try {
+            net.dnorberg.rivencraft.compat.RuinsCompatibility.registerAge(id, terrainFeatures);
             server.levels.put(key, level);
             level.getWorldBorder().setAbsoluteMaxSize(server.getAbsoluteMaxWorldSize());
             server.getPlayerList().addWorldborderListener(level);
@@ -518,11 +607,10 @@ public final class RuntimeAgeBackend {
             Rivencraft.LOGGER.info("Loaded 26.3 prototype Age {} with seed {}", id, seed);
             return level;
         } catch (RuntimeException exception) {
-            server.levels.remove(key);
-            try {
-                level.close();
-            } catch (IOException closeException) {
-                exception.addSuppressed(closeException);
+            try { closeFailedCreation(server, level); }
+            catch (RuntimeException cleanup) {
+                exception.addSuppressed(cleanup);
+                throw new FailedAgeCleanupException(exception);
             }
             throw exception;
         }

ports/mc263/src/main/java/net/dnorberg/rivencraft/client/AgeCatalogClient.java

@@ -27,6 +27,8 @@ public final class AgeCatalogClient {
     @SubscribeEvent
     public static void register(RegisterClientPayloadHandlersEvent event) {
         event.register(net.dnorberg.rivencraft.network.WritingDeskCatalogPayload.TYPE, ClientWritingDeskCatalog::handle);
+        event.register(net.dnorberg.rivencraft.network.SereneAgeWhitelistPayload.TYPE, (payload, context) ->
+                net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility.acceptClient(payload.dimensionId(), payload.enabled()));
         event.register(AgeCatalogPayload.TYPE, (payload, context) -> {
             if (!(context.listener() instanceof ClientPacketListener listener)) return;
             net.dnorberg.rivencraft.age.PortAgeColors.updateClient(payload.colors());

ports/mc263/src/main/java/net/dnorberg/rivencraft/client/LinkModifierScreen.java

@@ -4,6 +4,9 @@ import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.item.LinkProperties;
 import net.dnorberg.rivencraft.menu.LinkModifierMenu;
 import net.dnorberg.rivencraft.network.SetLinkModifierTitlePayload;
+import net.dnorberg.rivencraft.network.SetLinkModifierSeedPayload;
+import com.mojang.blaze3d.platform.InputConstants;
+import net.minecraft.client.input.MouseButtonEvent;
 import net.minecraft.client.gui.GuiGraphicsExtractor;
 import net.minecraft.client.gui.components.EditBox;
 import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen;
@@ -28,8 +31,13 @@ public final class LinkModifierScreen extends AbstractContainerScreen<LinkModifi
             LinkModifierMenu.TOGGLE_INTRA_ONLY, LinkModifierMenu.TOGGLE_MOMENTUM, LinkModifierMenu.TOGGLE_RELATIVE, LinkModifierMenu.TOGGLE_PLATFORM};
     private static final String[] NAMES = {"disarm", "intra_linking", "intra_linking_only", "maintain_momentum", "relative_link", "generate_platform"};
     private EditBox titleInput;
+    private EditBox seedInput;
+    private Identifier seedAge;
+    private long lastSeed = Long.MIN_VALUE;
     private ItemStack lastBook = ItemStack.EMPTY;
     private boolean refreshing;
+    private Button retireButton;
+    private Button confirmRetireButton;
     private final Button[] options = new Button[6];
 
     public LinkModifierScreen(LinkModifierMenu menu, Inventory inventory, Component title) {
@@ -46,6 +54,11 @@ public final class LinkModifierScreen extends AbstractContainerScreen<LinkModifi
             if (!refreshing) ClientPacketDistributor.sendToServer(new SetLinkModifierTitlePayload(menu.containerId, value));
         });
         addRenderableWidget(titleInput);
+        seedInput = new EditBox(font, leftPos + 80, topPos + 15, 87, 14,
+                Component.translatable("screen.rivencraft.link_modifier.seed"));
+        seedInput.setMaxLength(21);
+        seedInput.setTooltip(Tooltip.create(Component.translatable("screen.rivencraft.link_modifier.seed_warning")));
+        addRenderableWidget(seedInput);
         for (int index = 0; index < options.length; index++) {
             final int option = index;
             options[index] = addRenderableWidget(new Button(leftPos + 5 + (index / 3) * 20,
@@ -63,8 +76,28 @@ public final class LinkModifierScreen extends AbstractContainerScreen<LinkModifi
             });
             options[index].setTooltip(Tooltip.create(label(index)));
         }
+        retireButton = addRenderableWidget(new RetirementButton(120, LinkModifierMenu.RETIRE_AGE, "retire", false));
+        confirmRetireButton = addRenderableWidget(new RetirementButton(140, LinkModifierMenu.CONFIRM_RETIRE_AGE, "confirm", true));
         refreshControls();
     }
+    private final class RetirementButton extends Button {
+        private final boolean danger;
+        RetirementButton(int x, int action, String name, boolean danger) {
+            super(leftPos + x, topPos + 32, 18, 18,
+                    Component.translatable("screen.rivencraft.link_modifier." + name), button -> {
+                        if (minecraft != null && minecraft.gameMode != null)
+                            minecraft.gameMode.handleInventoryButtonClick(menu.containerId, action);
+                    }, DEFAULT_NARRATION);
+            this.danger = danger;
+            setTooltip(Tooltip.create(getMessage()));
+        }
+        @Override protected void extractContents(GuiGraphicsExtractor graphics, int mouseX, int mouseY, float partialTick) {
+            int x = getX(), y = getY();
+            graphics.fill(x, y, x + 18, y + 18, isHoveredOrFocused() ? 0xFFFFFFFF : 0xFFAAAAAA);
+            graphics.fill(x + 2, y + 2, x + 17, y + 17, danger ? 0xFFAA5555
+                    : menu.awaitingRetirementConfirmation() ? 0xFFBBBBBB : 0xFF777777);
+        }
+    }
     @Override protected void containerTick() { refreshControls(); }
     private void refreshControls() {
         ItemStack book = menu.book();
@@ -80,6 +113,28 @@ public final class LinkModifierScreen extends AbstractContainerScreen<LinkModifi
             }
         }
         titleInput.setEditable(!book.isEmpty());
+        boolean canRetire = minecraft != null && minecraft.player != null && menu.canRetire(minecraft.player);
+        if (retireButton != null) {
+            retireButton.visible = canRetire;
+            retireButton.active = canRetire && !menu.awaitingRetirementConfirmation();
+            confirmRetireButton.visible = canRetire && menu.awaitingRetirementConfirmation();
+            confirmRetireButton.active = confirmRetireButton.visible;
+        }
+        Identifier age = book.get(Rivencraft.AGE_BOOK_ID.get());
+        if (!java.util.Objects.equals(seedAge, age)) {
+            seedInput.setFocused(false);
+            seedAge = age;
+            seedInput.setValue(Long.toString(menu.seed()));
+            lastSeed = menu.seed();
+        }
+        seedInput.visible = menu.hasSeed();
+        seedInput.setEditable(seedInput.visible);
+        if (!seedInput.visible) seedInput.setFocused(false);
+        else if (!seedInput.isFocused() && (lastSeed != menu.seed()
+                || !seedInput.getValue().equals(Long.toString(menu.seed())))) {
+            lastSeed = menu.seed();
+            seedInput.setValue(Long.toString(lastSeed));
+        }
         for (int i = 0; i < options.length; i++) if (options[i] != null) {
             options[i].active = available(i);
             Component label = label(i);
@@ -97,7 +152,30 @@ public final class LinkModifierScreen extends AbstractContainerScreen<LinkModifi
         return name.copy().append(selected(index,
                 menu.book().getOrDefault(Rivencraft.LINK_PROPERTIES.get(), LinkProperties.NONE)) ? ": On" : ": Off");
     }
+    private void submitSeed() {
+        if (seedInput.visible && seedAge != null && !seedInput.getValue().equals(Long.toString(menu.seed())))
+            ClientPacketDistributor.sendToServer(new SetLinkModifierSeedPayload(menu.containerId, seedAge, seedInput.getValue()));
+    }
+    @Override public boolean mouseClicked(MouseButtonEvent event, boolean doubleClick) {
+        if (seedInput.isFocused() && !seedInput.isMouseOver(event.x(), event.y())) {
+            submitSeed();
+            seedInput.setFocused(false);
+        }
+        return super.mouseClicked(event, doubleClick);
+    }
     @Override public boolean keyPressed(KeyEvent event) {
+        if (seedInput != null && seedInput.isFocused()) {
+            if (event.key() == InputConstants.KEY_RETURN || event.key() == InputConstants.KEY_NUMPADENTER) {
+                submitSeed();
+                seedInput.setFocused(false);
+                setFocused(null);
+                return true;
+            }
+            if (!event.isEscape()) {
+                seedInput.keyPressed(event);
+                return true;
+            }
+        }
         if (titleInput != null && titleInput.isFocused() && !event.isEscape()) {
             titleInput.keyPressed(event);
             return true; // Character input must never activate inventory/hotbar shortcuts.

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/RuinsCompatibility.java

@@ -0,0 +1,84 @@
+package net.dnorberg.rivencraft.compat;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import net.dnorberg.rivencraft.age.PortTerrainFeaturePlan;
+import net.minecraft.resources.Identifier;
+import net.neoforged.fml.ModList;
+
+/** Small optional bridge between frozen Age pages and Ruins' dimension gate. */
+public final class RuinsCompatibility {
+    private static final Set<Identifier> KNOWN_AGES = ConcurrentHashMap.newKeySet();
+    private static final Map<Identifier, Map<Identifier, Integer>> AUTHORED_TEMPLATES =
+            new ConcurrentHashMap<>();
+
+    private RuinsCompatibility() {}
+
+    public static void register() {
+        if (ModList.get().isLoaded("ruins")) RuinsEventAdapter.register();
+        net.neoforged.neoforge.common.NeoForge.EVENT_BUS.addListener(RuinsCompatibility::onLevelUnload);
+        net.neoforged.neoforge.common.NeoForge.EVENT_BUS.addListener(
+                (net.neoforged.neoforge.event.server.ServerAboutToStartEvent event) -> RuinsTemplatePages.refresh());
+        net.neoforged.neoforge.common.NeoForge.EVENT_BUS.addListener(
+                (net.neoforged.neoforge.event.server.ServerStoppedEvent event) -> onServerStopping());
+    }
+
+    public static void registerAge(Identifier id, PortTerrainFeaturePlan plan) {
+        if (!ModList.get().isLoaded("ruins")) return;
+        Map<Identifier, Integer> selected = templateCounts(plan == null ? List.of() : plan.ruins());
+        if (selected.isEmpty()) AUTHORED_TEMPLATES.remove(id);
+        else AUTHORED_TEMPLATES.put(id, selected);
+        KNOWN_AGES.add(id);
+    }
+
+    public static void onLevelUnload(net.neoforged.neoforge.event.level.LevelEvent.Unload event) {
+        if (event.getLevel() instanceof net.minecraft.server.level.ServerLevel level) {
+            var id = level.dimension().identifier();
+            KNOWN_AGES.remove(id);
+            AUTHORED_TEMPLATES.remove(id);
+        }
+    }
+
+    /** Called only by the optional Ruins FileHandler mixin. */
+    public static boolean allowsAge(Identifier dimension) {
+        return AUTHORED_TEMPLATES.containsKey(dimension);
+    }
+
+    public static boolean isKnownAge(Identifier dimension) {
+        return KNOWN_AGES.contains(dimension);
+    }
+
+    public static boolean permits(Identifier dimension, Identifier template) {
+        return templateCount(dimension, template) > 0;
+    }
+
+    public static int templateCount(Identifier dimension, Identifier template) {
+        return AUTHORED_TEMPLATES.getOrDefault(dimension, Map.of()).getOrDefault(template, 0);
+    }
+
+    /** Extra pages increase attempts, without making distinct template choices denser. */
+    public static int attemptsPerChunk(Identifier dimension, int configuredAttempts) {
+        return attemptsPerChunk(configuredAttempts, AUTHORED_TEMPLATES.get(dimension));
+    }
+
+    static int attemptsPerChunk(int configuredAttempts, Map<Identifier, Integer> counts) {
+        if (counts == null || counts.isEmpty()) return configuredAttempts;
+        int duplicates = counts.values().stream().mapToInt(count -> count - 1).sum();
+        return (int) Math.min(Math.max(configuredAttempts, 32L), (long) configuredAttempts + duplicates);
+    }
+
+    static Map<Identifier, Integer> templateCounts(List<Identifier> choices) {
+        Map<Identifier, Integer> counts = new java.util.HashMap<>();
+        for (Identifier choice : choices) {
+            if (RuinsTemplatePages.contains(choice)) counts.merge(choice, 1, Integer::sum);
+        }
+        return Map.copyOf(counts);
+    }
+
+    public static void onServerStopping() {
+        KNOWN_AGES.clear();
+        AUTHORED_TEMPLATES.clear();
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/RuinsEventAdapter.java

@@ -0,0 +1,53 @@
+package net.dnorberg.rivencraft.compat;
+
+import atomicstryker.ruins.common.EventRuinTemplateSpawn;
+import atomicstryker.ruins.common.RuinTemplate;
+import java.util.Collection;
+import java.util.Comparator;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.util.RandomSource;
+import net.neoforged.neoforge.common.NeoForge;
+
+/** Loaded only when Ruins is present. Its pre-spawn event can veto exact templates. */
+public final class RuinsEventAdapter {
+    private RuinsEventAdapter() {}
+
+    static void register() {
+        NeoForge.EVENT_BUS.addListener(RuinsEventAdapter::onTemplateSpawn);
+    }
+
+    private static void onTemplateSpawn(EventRuinTemplateSpawn event) {
+        if (!event.isPrePhase || event.testingRuin
+                || !(event.getLevel() instanceof ServerLevel level)
+                || !RuinsCompatibility.isKnownAge(level.dimension().identifier())) return;
+
+        var template = RuinsTemplatePages.featureId(event.template.getName());
+        if (!RuinsTemplatePages.contains(template)
+                || !RuinsCompatibility.permits(level.dimension().identifier(), template)) event.setCancelled(true);
+    }
+
+    /** Preserve Ruins' weights and multiply each by its authored page count. */
+    public static Object chooseTemplate(net.minecraft.resources.Identifier dimension,
+                                        Collection<?> pool, RandomSource random) {
+        if (pool == null || pool.isEmpty()) return null;
+        var candidates = pool.stream().filter(RuinTemplate.class::isInstance)
+                .map(RuinTemplate.class::cast)
+                .filter(template -> RuinsCompatibility.permits(dimension,
+                        RuinsTemplatePages.featureId(template.getName())))
+                .sorted(Comparator.comparing(RuinTemplate::getName)).toList();
+        double total = candidates.stream().mapToDouble(template -> authoredWeight(dimension, template)).sum();
+        if (total <= 0.0) return null;
+        double roll = random.nextDouble() * total;
+        for (RuinTemplate candidate : candidates) {
+            roll -= authoredWeight(dimension, candidate);
+            if (roll < 0.0) return candidate;
+        }
+        return candidates.getLast();
+    }
+
+    private static double authoredWeight(net.minecraft.resources.Identifier dimension,
+                                         RuinTemplate template) {
+        return Math.max(0.0, template.getWeight()) * RuinsCompatibility.templateCount(dimension,
+                RuinsTemplatePages.featureId(template.getName()));
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/RuinsTemplatePages.java

@@ -0,0 +1,166 @@
+package net.dnorberg.rivencraft.compat;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.HexFormat;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.writing.PortSymbolPages;
+import net.minecraft.resources.Identifier;
+import net.neoforged.fml.ModList;
+import net.neoforged.fml.loading.FMLPaths;
+
+/** Discovers Ruins' template filenames without making its jar mandatory. */
+public final class RuinsTemplatePages {
+    public static final Identifier CATEGORY = Identifier.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "ruins");
+    private static final String PREFIX = "ruins/";
+    private static volatile Map<Identifier, String> names = Map.of();
+    private static volatile boolean initialized;
+
+    private RuinsTemplatePages() {}
+
+    public static void refresh() {
+        if (!ModList.get().isLoaded("ruins")) {
+            names = Map.of();
+            initialized = true;
+            return;
+        }
+        Map<Identifier, String> discovered = new HashMap<>();
+        Map<String, String> sources = new HashMap<>();
+        Set<String> duplicateNames = new HashSet<>();
+        // Ruins itself reads <gameDir>/config/ruins_config, not NeoForge's
+        // overrideable CONFIGDIR; mirror its active folder exactly.
+        Path configured = FMLPaths.GAMEDIR.get().resolve("config/ruins_config");
+        if (Files.isDirectory(configured)) {
+            try (var paths = Files.walk(configured)) {
+                paths.filter(Files::isRegularFile)
+                        .filter(path -> configured.relativize(path).getNameCount() == 2)
+                        .filter(path -> isTemplate(path.getFileName().toString()))
+                        .sorted().forEach(path -> add(discovered, sources, duplicateNames,
+                                path.getFileName().toString(), configured.relativize(path).toString()));
+            } catch (IOException exception) {
+                Rivencraft.LOGGER.warn("Could not read Ruins templates from {}", configured, exception);
+            }
+        }
+        // Ruins extracts this archive on first launch. It also supplies the creative
+        // pages before extraction has completed on a fresh installation.
+        if (discovered.isEmpty() && !Files.isDirectory(configured)) {
+            try (InputStream stream = RuinsTemplatePages.class.getClassLoader()
+                    .getResourceAsStream("assets/ruins_config.zip")) {
+                if (stream != null) {
+                    try (ZipInputStream zip = new ZipInputStream(stream)) {
+                        ZipEntry entry;
+                        while ((entry = zip.getNextEntry()) != null) {
+                            if (!entry.isDirectory()) {
+                                String name = entry.getName();
+                                name = name.substring(name.lastIndexOf('/') + 1);
+                                if (isTemplate(name)) add(discovered, sources, duplicateNames,
+                                        name, entry.getName());
+                            }
+                        }
+                    }
+                }
+            } catch (IOException exception) {
+                Rivencraft.LOGGER.warn("Could not read bundled Ruins templates", exception);
+            }
+        }
+        // Ruins' spawn event exposes only the basename. If two directories use
+        // that basename, Rivencraft cannot identify which structure was chosen.
+        // Disable the bridge instead of advertising pages with ambiguous effects.
+        if (!duplicateNames.isEmpty()) {
+            Rivencraft.LOGGER.error("Ruins compatibility disabled: duplicate template names {}. "
+                    + "Give every .tml file a unique basename.", duplicateNames);
+            names = Map.of();
+            initialized = true;
+            return;
+        }
+        names = Map.copyOf(discovered);
+        initialized = true;
+    }
+
+    public static List<String> templates() {
+        if (!initialized) refresh();
+        List<String> templates = new ArrayList<>(names.values());
+        templates.sort(Comparator.comparing(name -> name.toLowerCase(Locale.ROOT)));
+        return List.copyOf(templates);
+    }
+
+    public static boolean isSymbol(Identifier id) {
+        return id.getNamespace().equals(Rivencraft.MOD_ID) && id.getPath().startsWith(PREFIX);
+    }
+
+    public static boolean contains(Identifier id) {
+        if (!initialized) refresh();
+        return isSymbol(id) && names.containsKey(id);
+    }
+
+    public static Identifier symbolId(String templateName) {
+        if (templateName.isBlank()) throw new IllegalArgumentException("Ruins template has no usable name");
+        // Hex is reversible and collision-free even for case-sensitive or Unicode
+        // filenames; normalizing to lowercase would merge distinct templates.
+        String key = HexFormat.of().formatHex(templateName.getBytes(StandardCharsets.UTF_8));
+        return Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, PREFIX + "t_" + key);
+    }
+
+    public static Identifier featureId(String templateName) {
+        return symbolId(templateName);
+    }
+
+    public static String fallbackName(Identifier symbolId) {
+        String encoded = symbolId.getPath().substring(PREFIX.length());
+        if (!encoded.startsWith("t_")) return encoded + " Ruin";
+        String name;
+        try {
+            name = new String(HexFormat.of().parseHex(encoded.substring(2)), StandardCharsets.UTF_8);
+        } catch (IllegalArgumentException exception) {
+            name = encoded;
+        }
+        return stripExtension(name).replace('_', ' ') + " Ruin";
+    }
+
+    public static PortSymbolPages.Entry definition(String templateName) {
+        Identifier id = featureId(templateName);
+        return new PortSymbolPages.Entry(id, CATEGORY.toString(),
+                "symbol.rivencraft.ruins.template." + id.getPath().substring(PREFIX.length()),
+                "symbol.rivencraft.ruins.description", "", "feature");
+    }
+
+    public static PortSymbolPages.Entry find(Identifier id) {
+        if (!initialized) refresh();
+        String name = names.get(id);
+        return name == null ? null : definition(name);
+    }
+
+    private static boolean isTemplate(String name) {
+        return name.toLowerCase(Locale.ROOT).endsWith(".tml");
+    }
+
+    private static String stripExtension(String name) {
+        return isTemplate(name) ? name.substring(0, name.length() - 4) : name;
+    }
+
+    private static void add(Map<Identifier, String> templates, Map<String, String> sources,
+                            Set<String> duplicateNames, String name, String source) {
+        String previousSource = sources.putIfAbsent(name, source);
+        if (previousSource != null && !previousSource.equals(source)) duplicateNames.add(name);
+        Identifier id = symbolId(name);
+        String previous = templates.putIfAbsent(id, name);
+        if (previous != null && !previous.equals(name)) {
+            Rivencraft.LOGGER.warn("Ruins templates {} and {} share page ID {}; using {}",
+                    previous, name, id, previous);
+        }
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/SereneSeasonsAdapter.java

@@ -0,0 +1,63 @@
+package net.dnorberg.rivencraft.compat;
+
+import java.util.ArrayList;
+import java.util.List;
+import net.dnorberg.rivencraft.age.PortSeasonPolicies.Mode;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.level.ServerLevel;
+import sereneseasons.api.season.Season;
+import sereneseasons.config.SeasonsConfig;
+import sereneseasons.init.ModConfig;
+import sereneseasons.season.SeasonHandler;
+import sereneseasons.season.SeasonSavedData;
+import sereneseasons.season.SeasonTime;
+
+/** Isolates references to optional Serene Seasons and GlitchCore classes. */
+final class SereneSeasonsAdapter {
+    private static final String WHITELIST_KEY = "dimension_settings.whitelisted_dimensions";
+
+    private SereneSeasonsAdapter() {
+    }
+
+    static boolean setServerWhitelist(Identifier dimensionId, boolean enabled) {
+        SeasonsConfig config = ModConfig.seasons;
+        if (config == null || config.whitelistedDimensions.contains(dimensionId.toString()) == enabled) return false;
+        List<String> dimensions = new ArrayList<>(config.whitelistedDimensions);
+        if (enabled) dimensions.add(dimensionId.toString());
+        else dimensions.removeIf(dimensionId.toString()::equals);
+        // GlitchCore rereads this config from disk before synchronizing new clients.
+        config.set(WHITELIST_KEY, dimensions);
+        config.write();
+        config.whitelistedDimensions = dimensions;
+        return true;
+    }
+
+    static void setClientWhitelist(Identifier dimensionId, boolean enabled) {
+        SeasonsConfig config = ModConfig.seasons;
+        if (config == null || config.whitelistedDimensions.contains(dimensionId.toString()) == enabled) return;
+        List<String> dimensions = new ArrayList<>(config.whitelistedDimensions);
+        if (enabled) dimensions.add(dimensionId.toString());
+        else dimensions.removeIf(dimensionId.toString()::equals);
+        config.whitelistedDimensions = dimensions;
+    }
+
+    static void holdSeason(ServerLevel level, Mode mode) {
+        SeasonSavedData data = SeasonHandler.getSeasonSavedData(level);
+        Season.SubSeason target = switch (mode) {
+            case ETERNAL_SPRING -> Season.SubSeason.MID_SPRING;
+            case ETERNAL_SUMMER -> Season.SubSeason.MID_SUMMER;
+            case ETERNAL_FALL -> Season.SubSeason.MID_AUTUMN;
+            case ETERNAL_WINTER -> Season.SubSeason.MID_WINTER;
+            default -> throw new IllegalArgumentException("Not an eternal season: " + mode);
+        };
+        int duration = SeasonTime.ZERO.getSubSeasonDuration();
+        int midpoint = target.ordinal() * duration + duration / 2;
+        // Reset well before the end of MID_* so the client never observes a
+        // different sub-season; avoid marking saved data dirty every tick.
+        int current = data.seasonCycleTicks;
+        if (current >= midpoint && current < midpoint + duration / 4) return;
+        data.seasonCycleTicks = midpoint;
+        data.setDirty();
+        SeasonHandler.sendSeasonUpdate(level);
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/SereneSeasonsCompatibility.java

@@ -0,0 +1,80 @@
+package net.dnorberg.rivencraft.compat;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.PortConfig;
+import net.dnorberg.rivencraft.age.PortSeasonPolicies;
+import net.dnorberg.rivencraft.age.PortSeasonPolicies.Mode;
+import net.dnorberg.rivencraft.age.RuntimeAgeBackend;
+import net.dnorberg.rivencraft.network.SereneAgeWhitelistPayload;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.neoforged.fml.ModList;
+import net.neoforged.neoforge.network.PacketDistributor;
+import net.neoforged.neoforge.event.level.LevelEvent;
+import net.neoforged.neoforge.event.entity.player.PlayerEvent;
+import net.neoforged.neoforge.event.tick.LevelTickEvent;
+
+/** Common optional boundary: only its guarded adapter loads Serene/GlitchCore APIs. */
+public final class SereneSeasonsCompatibility {
+    private static final java.util.concurrent.atomic.AtomicBoolean WARNED = new java.util.concurrent.atomic.AtomicBoolean();
+    private SereneSeasonsCompatibility() {}
+    public static boolean available() { return ModList.get().isLoaded("sereneseasons"); }
+    private static boolean isAge(Identifier id) { return id.getNamespace().equals("rivencraft") && id.getPath().startsWith("age/"); }
+    private static Boolean enabled(ServerLevel level) {
+        var policy = PortSeasonPolicies.get(level.getServer()).forLevel(level);
+        if (policy.mode() != Mode.NO_SEASONS && !policy.authored() && !PortConfig.AUTO_WHITELIST_SERENE_AGES.get()) return null;
+        return policy.mode() != Mode.NO_SEASONS;
+    }
+    public static void apply(ServerLevel level) {
+        if (!available() || !isAge(level.dimension().identifier())) return;
+        try {
+            Boolean enabled = enabled(level);
+            if (enabled == null) return;
+            var id = level.dimension().identifier();
+            SereneSeasonsAdapter.setServerWhitelist(id, enabled);
+            if (enabled) {
+                var mode = PortSeasonPolicies.get(level.getServer()).forLevel(level).mode();
+                if (mode.eternal()) SereneSeasonsAdapter.holdSeason(level, mode);
+            }
+            for (var player : level.getServer().getPlayerList().getPlayers()) send(player, id, enabled);
+        } catch (RuntimeException | LinkageError e) { warn(e); }
+    }
+    public static void onLevelLoad(LevelEvent.Load event) {
+        if (event.getLevel() instanceof ServerLevel level && isAge(level.dimension().identifier())
+                && RuntimeAgeBackend.savedAges(level.getServer()).containsKey(level.dimension().identifier())) apply(level);
+    }
+    public static void onLogin(PlayerEvent.PlayerLoggedInEvent event) {
+        if (!available() || !(event.getEntity() instanceof ServerPlayer player)) return;
+        for (var level : player.level().getServer().getAllLevels()) if (isAge(level.dimension().identifier())) {
+            Boolean enabled = enabled(level);
+            if (enabled != null) send(player, level.dimension().identifier(), enabled);
+        }
+    }
+    public static void onLevelTickPost(LevelTickEvent.Post event) {
+        if (!available() || !(event.getLevel() instanceof ServerLevel level) || !isAge(level.dimension().identifier())) return;
+        var policy = PortSeasonPolicies.get(level.getServer()).forLevel(level);
+        if (!policy.mode().eternal() || !policy.authored() && !PortConfig.AUTO_WHITELIST_SERENE_AGES.get()) return;
+        try { SereneSeasonsAdapter.holdSeason(level, policy.mode()); }
+        catch (RuntimeException | LinkageError e) { warn(e); }
+    }
+    public static void retired(MinecraftServer server, Identifier id) {
+        if (!available()) return;
+        try {
+            SereneSeasonsAdapter.setServerWhitelist(id, false);
+            for (var player : server.getPlayerList().getPlayers()) send(player, id, false);
+        } catch (RuntimeException | LinkageError e) { warn(e); }
+    }
+    private static void send(ServerPlayer player, Identifier id, boolean enabled) {
+        PacketDistributor.sendToPlayer(player, new SereneAgeWhitelistPayload(id, enabled));
+    }
+    public static void acceptClient(Identifier id, boolean enabled) {
+        if (!available() || !isAge(id)) return;
+        try { SereneSeasonsAdapter.setClientWhitelist(id, enabled); }
+        catch (RuntimeException | LinkageError e) { warn(e); }
+    }
+    private static void warn(Throwable e) {
+        if (WARNED.compareAndSet(false, true)) Rivencraft.LOGGER.warn("Could not apply optional Serene Seasons policy", e);
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/TerraBlenderBiomes.java

@@ -0,0 +1,59 @@
+package net.dnorberg.rivencraft.compat;
+
+import java.util.List;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.Holder;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.Identifier;
+import net.minecraft.world.level.biome.Biome;
+import net.neoforged.fml.ModList;
+import net.neoforged.neoforge.event.TagsUpdatedEvent;
+
+/** Optional API boundary with registry-scoped pools and cheap worldgen membership queries. */
+public final class TerraBlenderBiomes {
+    private record Pools(List<Identifier> overworld, List<Identifier> nether) {}
+    private static final Pools EMPTY = new Pools(List.of(), List.of());
+    private static final Map<RegistryAccess, Pools> POOLS = new WeakHashMap<>();
+    private static final Map<Holder<Biome>, Boolean> NETHER_MEMBERSHIP = new WeakHashMap<>();
+    private static final AtomicBoolean WARNED = new AtomicBoolean();
+    private TerraBlenderBiomes() {}
+    public static List<Identifier> overworld(HolderLookup.Provider registries) { return prepare(registries).overworld(); }
+    public static List<Identifier> nether(HolderLookup.Provider registries) { return prepare(registries).nether(); }
+    public static synchronized boolean isNether(Holder<Biome> biome) {
+        return Boolean.TRUE.equals(NETHER_MEMBERSHIP.get(biome));
+    }
+    public static void onServerAboutToStart(net.neoforged.neoforge.event.server.ServerAboutToStartEvent event) {
+        // TerraBlender loads data-driven regions at normal priority in this event.
+        // Refresh after that, even if tags were seen before those regions existed.
+        synchronized (TerraBlenderBiomes.class) { POOLS.remove(event.getServer().registryAccess()); }
+        prepare(event.getServer().registryAccess());
+    }
+    public static void onTagsUpdated(TagsUpdatedEvent event) {
+        // Server/client registry objects have independent cache entries.
+        synchronized (TerraBlenderBiomes.class) { POOLS.remove(event.getRegistries()); }
+        prepare(event.getRegistries());
+    }
+    private static synchronized Pools prepare(HolderLookup.Provider provider) {
+        if (!ModList.get().isLoaded("terrablender") || !(provider instanceof RegistryAccess registries)) return EMPTY;
+        Pools cached = POOLS.get(registries);
+        if (cached != null) return cached;
+        Pools pools = EMPTY;
+        try {
+            pools = new Pools(TerraBlenderRegionAdapter.collect(registries, false),
+                    TerraBlenderRegionAdapter.collect(registries, true));
+        } catch (RuntimeException | LinkageError exception) {
+            if (WARNED.compareAndSet(false, true)) Rivencraft.LOGGER.warn(
+                    "TerraBlender biome regions could not be read; using registry tags and native biome pools", exception);
+        }
+        POOLS.put(registries, pools);
+        var nether = java.util.Set.copyOf(pools.nether());
+        registries.lookupOrThrow(Registries.BIOME).listElements().forEach(holder ->
+                NETHER_MEMBERSHIP.put(holder, nether.contains(holder.key().identifier())));
+        return pools;
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/TerraBlenderRegionAdapter.java

@@ -0,0 +1,35 @@
+package net.dnorberg.rivencraft.compat;
+
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.resources.Identifier;
+import net.minecraft.world.level.biome.Biome;
+import terrablender.api.Region;
+import terrablender.api.RegionType;
+import terrablender.api.Regions;
+
+/** Loaded only after the optional TerraBlender mod is confirmed present. */
+final class TerraBlenderRegionAdapter {
+    private TerraBlenderRegionAdapter() {}
+
+    static List<Identifier> collect(RegistryAccess registries, boolean nether) {
+        var biomes = registries.lookupOrThrow(Registries.BIOME);
+        RegionType type = nether ? RegionType.NETHER : RegionType.OVERWORLD;
+        Set<Identifier> ids = new LinkedHashSet<>();
+        for (Region region : Regions.get(type)) {
+            region.addBiomes(biomes, mapping -> {
+                ResourceKey<Biome> key = mapping.getSecond();
+                Identifier id = key.identifier();
+                // Vanilla's default region is always present. Only additions from
+                // other mods extend an Age's existing deterministic biome pool.
+                if (!id.getNamespace().equals("minecraft") && !id.equals(
+                        net.dnorberg.rivencraft.writing.PortRegistryPages.DEFERRED_PLACEHOLDER) && biomes.containsKey(id)) ids.add(id);
+            });
+        }
+        return ids.stream().sorted().toList();
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/compat/jei/RivencraftJeiPlugin.java

@@ -0,0 +1,234 @@
+package net.dnorberg.rivencraft.compat.jei;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Set;
+import java.util.stream.Collectors;
+import mezz.jei.api.IModPlugin;
+import mezz.jei.api.JeiPlugin;
+import mezz.jei.api.constants.VanillaTypes;
+import mezz.jei.api.gui.builder.IRecipeLayoutBuilder;
+import mezz.jei.api.gui.ingredient.IRecipeSlotsView;
+import mezz.jei.api.helpers.IGuiHelper;
+import mezz.jei.api.recipe.IFocusGroup;
+import mezz.jei.api.recipe.types.IRecipeType;
+import mezz.jei.api.recipe.category.AbstractRecipeCategory;
+import mezz.jei.api.registration.IRecipeCatalystRegistration;
+import mezz.jei.api.registration.IRecipeCategoryRegistration;
+import mezz.jei.api.registration.IRecipeRegistration;
+import mezz.jei.api.registration.ISubtypeRegistration;
+import mezz.jei.api.registration.IExtraIngredientRegistration;
+import mezz.jei.api.ingredients.subtypes.ISubtypeInterpreter;
+import mezz.jei.api.runtime.IJeiRuntime;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.item.LinkProperties;
+import net.dnorberg.rivencraft.writing.PortSymbolPages;
+import net.dnorberg.rivencraft.registry.ModCreativeTabs;
+import net.dnorberg.rivencraft.writing.InkModifierIngredients;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.GuiGraphicsExtractor;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.MutableComponent;
+import net.minecraft.resources.Identifier;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+/** Loaded by JEI's plugin scanner only when JEI is installed. No common mod class references this type. */
+@JeiPlugin
+public final class RivencraftJeiPlugin implements IModPlugin {
+    private static final IRecipeType<WritingGuide> WRITING =
+            IRecipeType.create(Rivencraft.MOD_ID, "writing", WritingGuide.class);
+    private static final IRecipeType<InkMixerGuide> INK_MIXER =
+            IRecipeType.create(Rivencraft.MOD_ID, "ink_mixer", InkMixerGuide.class);
+
+    @Override
+    public Identifier getPluginUid() {
+        return Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "jei_writing");
+    }
+
+    @Override
+    public void registerItemSubtypes(ISubtypeRegistration registration) {
+        registration.registerSubtypeInterpreter(Rivencraft.PAGE.get(),
+                (ISubtypeInterpreter<ItemStack>) (stack, context) -> {
+                    PageContent content = PageItem.content(stack);
+                    return switch (content.kind()) {
+                        case BLANK -> "blank";
+                        case LINK_PANEL -> "link_panel:" + stack.getOrDefault(
+                                Rivencraft.LINK_PROPERTIES.get(), LinkProperties.NONE).flags();
+                        case SYMBOL -> "symbol:" + content.symbol().orElseThrow().id();
+                        case UNRESOLVED_SYMBOL -> "unresolved:" + content.symbol().orElseThrow().id();
+                    };
+                });
+        registration.registerSubtypeInterpreter(Rivencraft.SYMBOL_PORTFOLIO.get(),
+                (ISubtypeInterpreter<ItemStack>) (stack, context) -> {
+                    Component name = stack.get(DataComponents.CUSTOM_NAME);
+                    return name == null ? "empty" : name.getString();
+                });
+    }
+
+    @Override
+    public void registerExtraIngredients(IExtraIngredientRegistration registration) {
+        List<ItemStack> pages = new ArrayList<>();
+        pages.addAll(PageItem.creativeLinkPanelPages());
+        var connection = Minecraft.getInstance().getConnection();
+        if (connection != null) {
+            pages.addAll(symbolPages(connection.registryAccess()));
+            pages.addAll(ModCreativeTabs.creativeSymbolPortfolios(connection.registryAccess()));
+        } else {
+            PortSymbolPages.sealedCandidateIds().stream().map(PageItem::createSymbolPage).forEach(pages::add);
+        }
+        registration.addExtraItemStacks(pages);
+    }
+
+    @Override
+    public void onRuntimeAvailable(IJeiRuntime runtime) {
+        // JEI discovers the base Page item as a blank stack; only authored pages belong in its list.
+        runtime.getIngredientManager().removeIngredientsAtRuntime(VanillaTypes.ITEM_STACK,
+                List.of(new ItemStack(Rivencraft.PAGE.get()), new ItemStack(Rivencraft.SYMBOL_PORTFOLIO.get())));
+        var connection = Minecraft.getInstance().getConnection();
+        if (connection == null) return;
+        Set<Identifier> known = runtime.getIngredientManager().getAllItemStacks().stream()
+                .filter(stack -> stack.is(Rivencraft.PAGE.get()))
+                .map(PageItem::content)
+                .filter(content -> content.kind() == PageContent.Kind.SYMBOL)
+                .map(content -> content.symbol().orElseThrow().id())
+                .collect(Collectors.toSet());
+        List<ItemStack> missing = symbolPages(connection.registryAccess()).stream()
+                .filter(stack -> !known.contains(PageItem.content(stack).symbol().orElseThrow().id()))
+                .toList();
+        if (!missing.isEmpty()) {
+            runtime.getIngredientManager().addIngredientsAtRuntime(VanillaTypes.ITEM_STACK, missing);
+        }
+        Set<String> knownPortfolios = runtime.getIngredientManager().getAllItemStacks().stream()
+                .filter(stack -> stack.is(Rivencraft.SYMBOL_PORTFOLIO.get()))
+                .map(stack -> stack.get(DataComponents.CUSTOM_NAME))
+                .filter(java.util.Objects::nonNull)
+                .map(Component::getString)
+                .collect(Collectors.toSet());
+        List<ItemStack> missingPortfolios = ModCreativeTabs.creativeSymbolPortfolios(connection.registryAccess())
+                .stream()
+                .filter(stack -> !knownPortfolios.contains(stack.getHoverName().getString()))
+                .toList();
+        if (!missingPortfolios.isEmpty()) {
+            runtime.getIngredientManager().addIngredientsAtRuntime(VanillaTypes.ITEM_STACK, missingPortfolios);
+        }
+    }
+
+    private static List<ItemStack> symbolPages(net.minecraft.core.HolderLookup.Provider registries) {
+        return PortSymbolPages.categories().stream().flatMap(category -> PortSymbolPages.pages(category, registries).stream()).toList();
+    }
+
+    @Override
+    public void registerCategories(IRecipeCategoryRegistration registration) {
+        IGuiHelper guiHelper = registration.getJeiHelpers().getGuiHelper();
+        registration.addRecipeCategories(new WritingCategory(guiHelper), new InkMixerCategory(guiHelper));
+    }
+
+    @Override
+    public void registerRecipes(IRecipeRegistration registration) {
+        registration.addItemStackInfo(new ItemStack(Rivencraft.LINK_MODIFIER_ITEM.get()),
+                Component.translatable("jei.rivencraft.link_modifier"));
+        ItemStack panel = PageItem.createLinkPanelPage();
+        ItemStack symbolPage = PageItem.createSymbolPage(new SymbolReference(
+                Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "terrain/standard")));
+        registration.addRecipes(WRITING, List.of(
+                new WritingGuide(List.of(new ItemStack(Items.PAPER), new ItemStack(Rivencraft.INK_VIAL.get())),
+                        panel, "jei.rivencraft.writing.link_panel_hand"),
+                new WritingGuide(List.of(symbolPage, new ItemStack(Items.PAPER), new ItemStack(Rivencraft.INK_VIAL.get())),
+                        symbolPage, "jei.rivencraft.writing.copy"),
+                new WritingGuide(List.of(new ItemStack(Items.LEATHER), panel),
+                        new ItemStack(Rivencraft.DESCRIPTIVE_BOOK.get()), "jei.rivencraft.writing.bind"),
+                new WritingGuide(List.of(panel, new ItemStack(Items.LEATHER)),
+                        new ItemStack(Rivencraft.LINKING_BOOK.get()), "jei.rivencraft.writing.linking_book")
+        ));
+        List<InkMixerGuide> mixerGuides = new ArrayList<>();
+        mixerGuides.add(new InkMixerGuide(panel, null));
+        InkModifierIngredients.builtIn().forEach(ingredient ->
+                mixerGuides.add(new InkMixerGuide(panel, ingredient)));
+        registration.addRecipes(INK_MIXER, mixerGuides);
+    }
+
+    @Override
+    public void registerRecipeCatalysts(IRecipeCatalystRegistration registration) {
+        registration.addCraftingStation(WRITING, Rivencraft.INK_VIAL.get(),
+                Rivencraft.WRITING_DESK_ITEM.get(), Rivencraft.BOOK_BINDER_ITEM.get());
+        registration.addCraftingStation(INK_MIXER, Rivencraft.INK_MIXER_ITEM.get());
+    }
+
+    private record WritingGuide(List<ItemStack> inputs, ItemStack output, String instructionKey) {}
+    private record InkMixerGuide(ItemStack panel, InkModifierIngredients.Ingredient additive) {}
+
+    private static final class InkMixerCategory extends AbstractRecipeCategory<InkMixerGuide> {
+        InkMixerCategory(IGuiHelper guiHelper) {
+            super(INK_MIXER, Component.translatable("jei.rivencraft.ink_mixer"),
+                    guiHelper.createDrawableIngredient(VanillaTypes.ITEM_STACK,
+                            new ItemStack(Rivencraft.INK_MIXER_ITEM.get())), 138, 110);
+        }
+
+        @Override
+        public void setRecipe(IRecipeLayoutBuilder builder, InkMixerGuide recipe, IFocusGroup focuses) {
+            builder.addInputSlot(2, 3).setStandardSlotBackground().add(new ItemStack(Items.PAPER));
+            builder.addInputSlot(23, 3).setStandardSlotBackground()
+                    .add(new ItemStack(Rivencraft.INK_VIAL.get()));
+            if (recipe.additive() != null)
+                builder.addInputSlot(44, 3).setStandardSlotBackground()
+                        .add(recipe.additive().item());
+            builder.addOutputSlot(112, 3).setOutputSlotBackground().add(recipe.panel());
+            builder.addOutputSlot(112, 46).setStandardSlotBackground()
+                    .add(new ItemStack(Items.GLASS_BOTTLE));
+        }
+
+        @Override
+        public void draw(InkMixerGuide recipe, IRecipeSlotsView slots, GuiGraphicsExtractor graphics,
+                         double mouseX, double mouseY) {
+            Component instructions = recipe.additive() == null
+                    ? Component.translatable("jei.rivencraft.ink_mixer.usage")
+                    : additiveInstructions(recipe.additive());
+            graphics.textWithWordWrap(Minecraft.getInstance().font, instructions, 2, 27, 104, 0xFF404040, false);
+        }
+
+        private static Component additiveInstructions(InkModifierIngredients.Ingredient additive) {
+            MutableComponent effects = Component.empty();
+            for (InkModifierIngredients.Effect effect : additive.effects()) {
+                if (!effects.getSiblings().isEmpty()) effects.append(", ");
+                effects.append(Component.translatable("jei.rivencraft.ink_mixer.effect",
+                        Component.translatable("item.rivencraft.link_property." + switch (effect.flag()) {
+                            case LinkProperties.DISARM -> "disarm";
+                            case LinkProperties.MAINTAIN_MOMENTUM -> "maintain_momentum";
+                            case LinkProperties.INTRA_LINKING -> "intra_linking";
+                            default -> throw new IllegalArgumentException("Unknown mixer modifier");
+                        }), Math.round(effect.chance() * 100)));
+            }
+            return Component.translatable("jei.rivencraft.ink_mixer.additive", effects);
+        }
+    }
+
+    private static final class WritingCategory extends AbstractRecipeCategory<WritingGuide> {
+        WritingCategory(IGuiHelper guiHelper) {
+            super(WRITING, Component.translatable("jei.rivencraft.writing"),
+                    guiHelper.createDrawableIngredient(VanillaTypes.ITEM_STACK,
+                            new ItemStack(Rivencraft.WRITING_DESK_ITEM.get())), 138, 80);
+        }
+
+        @Override
+        public void setRecipe(IRecipeLayoutBuilder builder, WritingGuide recipe, IFocusGroup focuses) {
+            for (int index = 0; index < recipe.inputs().size(); index++) {
+                builder.addInputSlot(2 + index * 21, 3).setStandardSlotBackground()
+                        .add(recipe.inputs().get(index));
+            }
+            builder.addOutputSlot(112, 3).setOutputSlotBackground().add(recipe.output());
+        }
+
+        @Override
+        public void draw(WritingGuide recipe, IRecipeSlotsView slots, GuiGraphicsExtractor graphics,
+                         double mouseX, double mouseY) {
+            graphics.textWithWordWrap(Minecraft.getInstance().font,
+                    Component.translatable(recipe.instructionKey()), 2, 27, 134, 0xFF404040, false);
+        }
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/item/PageItem.java

@@ -30,6 +30,17 @@ public final class PageItem extends Item {
         return stack;
     }
 
+    /** All eight mixer-produced variants, shared by Creative and optional JEI. */
+    public static java.util.List<ItemStack> creativeLinkPanelPages() {
+        int[] flags = {LinkProperties.DISARM, LinkProperties.MAINTAIN_MOMENTUM, LinkProperties.INTRA_LINKING};
+        var panels = new java.util.ArrayList<ItemStack>();
+        for (int combination = 0; combination < 8; combination++) {
+            int selected = 0;
+            for (int bit = 0; bit < flags.length; bit++) if ((combination & (1 << bit)) != 0) selected |= flags[bit];
+            panels.add(createLinkPanelPage(selected));
+        }
+        return java.util.List.copyOf(panels);
+    }
     public static boolean isLinkPanel(ItemStack stack) {
         return stack.is(Rivencraft.PAGE.get()) && stack.getOrDefault(Rivencraft.LINK_PANEL_PAGE.get(), false);
     }

ports/mc263/src/main/java/net/dnorberg/rivencraft/menu/LinkModifierMenu.java

@@ -12,15 +12,25 @@ 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.Slot;
+import net.minecraft.world.inventory.DataSlot;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.resources.Identifier;
+import net.dnorberg.rivencraft.age.RuntimeAgeBackend;
 import net.minecraft.world.item.ItemStack;
 
 /** 1.21.1's persistent single-book editing station, adapted to 26.3. */
 public final class LinkModifierMenu extends AbstractContainerMenu {
     public static final int TOGGLE_DISARM = 1, TOGGLE_MOMENTUM = 2, TOGGLE_INTRA = 3,
-            TOGGLE_INTRA_ONLY = 5, TOGGLE_RELATIVE = 6, TOGGLE_PLATFORM = 7;
+            TOGGLE_INTRA_ONLY = 5, TOGGLE_RELATIVE = 6, TOGGLE_PLATFORM = 7,
+            RETIRE_AGE = 4, CONFIRM_RETIRE_AGE = 8;
     private final LinkModifierBlockEntity modifier;
     private final Container books;
     private final Player owner;
+    private final int[] seedWords = new int[4];
+    private boolean clientHasSeed;
+    private boolean clientRetirementArmed;
+    private Identifier pendingAge;
+    private ItemStack pendingBook = ItemStack.EMPTY;
     public LinkModifierMenu(int id, Inventory inventory, RegistryFriendlyByteBuf data) {
         this(id, inventory, inventory.player.level().getBlockEntity(data.readBlockPos())
                 instanceof LinkModifierBlockEntity found ? found : null);
@@ -30,9 +40,25 @@ public final class LinkModifierMenu extends AbstractContainerMenu {
         this.modifier = modifier;
         books = modifier == null ? new SimpleContainer(1) : modifier;
         owner = inventory.player;
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return awaitingRetirementConfirmation() ? 1 : 0; }
+            @Override public void set(int value) { clientRetirementArmed = value != 0; }
+        });
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return hasSeed() ? 1 : 0; }
+            @Override public void set(int value) { clientHasSeed = value != 0; }
+        });
+        for (int i = 0; i < seedWords.length; i++) {
+            final int word = i;
+            addDataSlot(new DataSlot() {
+                @Override public int get() { return (int) ((seed() >>> (word * 16)) & 0xffffL); }
+                @Override public void set(int value) { seedWords[word] = value & 0xffff; }
+            });
+        }
         addSlot(new Slot(books, 0, 80, 35) {
             @Override public boolean mayPlace(ItemStack stack) { return isBook(stack); }
             @Override public int getMaxStackSize() { return 1; }
+            @Override public void setChanged() { super.setChanged(); resetRetirement(); }
         });
         for (int row = 0; row < 3; row++) for (int col = 0; col < 9; col++)
             addSlot(new Slot(inventory, col + row * 9 + 9, 8 + col * 18, 84 + row * 18));
@@ -42,9 +68,92 @@ public final class LinkModifierMenu extends AbstractContainerMenu {
         return stack.is(Rivencraft.LINKING_BOOK.get()) || stack.is(Rivencraft.DESCRIPTIVE_BOOK.get());
     }
     public ItemStack book() { return books.getItem(0); }
+    public boolean hasSeed() {
+        if (!book().is(Rivencraft.DESCRIPTIVE_BOOK.get()) || !book().has(Rivencraft.AGE_BOOK_ID.get())) return false;
+        return owner.level().isClientSide() ? clientHasSeed
+                : RuntimeAgeBackend.savedAges(((ServerPlayer) owner).level().getServer())
+                        .containsKey(book().get(Rivencraft.AGE_BOOK_ID.get()));
+    }
+    public long seed() {
+        if (owner.level().isClientSide()) {
+            long value = 0;
+            for (int i = 0; i < seedWords.length; i++) value |= (seedWords[i] & 0xffffL) << (i * 16);
+            return value;
+        }
+        return hasSeed() ? RuntimeAgeBackend.savedAges(((ServerPlayer) owner).level().getServer())
+                .get(book().get(Rivencraft.AGE_BOOK_ID.get())) : 0;
+    }
+    public boolean canRetire(Player player) {
+        return net.minecraft.commands.Commands.LEVEL_GAMEMASTERS.check(player.permissions()) && hasSeed();
+    }
+    public boolean awaitingRetirementConfirmation() {
+        return owner.level().isClientSide() ? clientRetirementArmed : pendingAge != null;
+    }
+    private void resetRetirement() { pendingAge = null; pendingBook = ItemStack.EMPTY; }
+    private boolean retireAge(Player player, boolean confirm) {
+        if (!(player instanceof ServerPlayer serverPlayer) || !canRetire(player)) { resetRetirement(); return false; }
+        Identifier age = book().get(Rivencraft.AGE_BOOK_ID.get());
+        if (!confirm) {
+            pendingAge = age;
+            pendingBook = book().copy();
+            broadcastChanges();
+            return true;
+        }
+        if (!age.equals(pendingAge) || !ItemStack.matches(book(), pendingBook)) {
+            resetRetirement();
+            broadcastChanges();
+            return false;
+        }
+        resetRetirement();
+        var server = serverPlayer.level().getServer();
+        var target = server.getLevel(net.minecraft.resources.ResourceKey.create(
+                net.minecraft.core.registries.Registries.DIMENSION, age));
+        String outcome;
+        boolean retired = false;
+        if (target != null && !target.players().isEmpty()) outcome = "occupied";
+        else {
+            try {
+                RuntimeAgeBackend.retire(server, age);
+                outcome = "retired";
+                retired = true;
+            } catch (RuntimeException exception) {
+                outcome = "storage_failed";
+                Rivencraft.LOGGER.warn("Could not retire Age {} from Link Modifier", age, exception);
+            }
+        }
+        player.sendSystemMessage(Component.translatable("message.rivencraft.link_modifier.delete." + outcome));
+        broadcastChanges();
+        return retired;
+    }
+    /** The expected Age prevents an in-flight edit from targeting a replacement book. */
+    public boolean setSeed(Player player, Identifier expectedAge, String text) {
+        if (player.level().isClientSide() || !stillValid(player) || !hasSeed()
+                || !(player instanceof ServerPlayer serverPlayer)) return false;
+        Identifier age = book().get(Rivencraft.AGE_BOOK_ID.get());
+        if (!age.equals(expectedAge)) return false;
+        resetRetirement();
+        boolean changed = false;
+        try {
+            if (text == null || text.length() > 21) throw new IllegalArgumentException("Invalid seed text");
+            long requested = Long.parseLong(text.strip());
+            var server = serverPlayer.level().getServer();
+            var level = server.getLevel(net.minecraft.resources.ResourceKey.create(
+                    net.minecraft.core.registries.Registries.DIMENSION, age));
+            if (level != null && !level.players().isEmpty()) throw new IllegalArgumentException("Age occupied");
+            RuntimeAgeBackend.reseed(server, age, requested);
+            changed = true;
+        } catch (IllegalArgumentException | IllegalStateException exception) {
+            // Invalid/occupied/missing Ages leave the existing book and seed intact.
+        }
+        player.sendSystemMessage(Component.translatable(changed ? "message.rivencraft.link_modifier.seed_changed"
+                : "message.rivencraft.link_modifier.seed_failed"));
+        broadcastChanges();
+        return changed;
+    }
     public boolean setTitle(Player player, String title) {
         if (player.level().isClientSide() || !stillValid(player) || !isBook(book())
                 || title == null || title.length() > 32) return false;
+        resetRetirement();
         String clean = title.strip();
         if (clean.isEmpty()) book().remove(DataComponents.CUSTOM_NAME);
         else book().set(DataComponents.CUSTOM_NAME, Component.literal(clean));
@@ -54,6 +163,7 @@ public final class LinkModifierMenu extends AbstractContainerMenu {
     }
     @Override public boolean clickMenuButton(Player player, int id) {
         if (player.level().isClientSide() || !stillValid(player) || !isBook(book())) return false;
+        if (id == RETIRE_AGE || id == CONFIRM_RETIRE_AGE) return retireAge(player, id == CONFIRM_RETIRE_AGE);
         int flag = switch (id) {
             case TOGGLE_DISARM -> LinkProperties.DISARM;
             case TOGGLE_MOMENTUM -> LinkProperties.MAINTAIN_MOMENTUM;
@@ -66,6 +176,7 @@ public final class LinkModifierMenu extends AbstractContainerMenu {
         };
         // Descriptive Books travel to an Age; Intra Linking is a Linking Book property.
         if (flag == 0 || (flag == LinkProperties.INTRA_LINKING || flag == LinkProperties.INTRA_LINKING_ONLY) && book().is(Rivencraft.DESCRIPTIVE_BOOK.get())) return false;
+        resetRetirement();
         int flags = book().getOrDefault(Rivencraft.LINK_PROPERTIES.get(), LinkProperties.NONE).flags();
         if (flag == LinkProperties.INTRA_LINKING_ONLY && (flags & LinkProperties.INTRA_LINKING_ONLY) == 0)
             flags |= LinkProperties.INTRA_LINKING;

ports/mc263/src/main/java/net/dnorberg/rivencraft/mixin/RuinsAttemptMixin.java

@@ -0,0 +1,25 @@
+package net.dnorberg.rivencraft.mixin;
+
+import com.llamalad7.mixinextras.injector.ModifyExpressionValue;
+import net.dnorberg.rivencraft.compat.RuinsCompatibility;
+import net.minecraft.world.level.Level;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Pseudo;
+import org.spongepowered.asm.mixin.injection.At;
+
+/** Increase Ruins' per-chunk attempt loop only for Ages with duplicated Ruins pages. */
+@Pseudo
+@Mixin(targets = "atomicstryker.ruins.common.RuinGenerator", remap = false)
+public abstract class RuinsAttemptMixin {
+    @ModifyExpressionValue(method = "generateNormal", at = @At(value = "FIELD",
+            target = "Latomicstryker/ruins/common/FileHandler;triesPerChunkNormal:I"), remap = false)
+    private int rivencraft$normalAttempts(int configured, Level level) {
+        return RuinsCompatibility.attemptsPerChunk(level.dimension().identifier(), configured);
+    }
+
+    @ModifyExpressionValue(method = "generateNether", at = @At(value = "FIELD",
+            target = "Latomicstryker/ruins/common/FileHandler;triesPerChunkNether:I"), remap = false)
+    private int rivencraft$netherAttempts(int configured, Level level) {
+        return RuinsCompatibility.attemptsPerChunk(level.dimension().identifier(), configured);
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/mixin/RuinsDimensionMixin.java

@@ -0,0 +1,38 @@
+package net.dnorberg.rivencraft.mixin;
+
+import net.dnorberg.rivencraft.compat.RuinsCompatibility;
+import net.dnorberg.rivencraft.compat.RuinsEventAdapter;
+import net.minecraft.resources.Identifier;
+import net.minecraft.util.RandomSource;
+import java.util.HashMap;
+import java.util.HashSet;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Pseudo;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+/** Ruins defaults to a fixed vanilla whitelist, so authored Ages need a narrow override. */
+@Pseudo
+@Mixin(targets = "atomicstryker.ruins.common.FileHandler", remap = false)
+public abstract class RuinsDimensionMixin {
+    @Shadow @Final private Identifier dimension;
+    @Shadow @Final private HashMap<String, HashSet<?>> templates;
+
+    @Inject(method = "allowsDimension", at = @At("HEAD"), cancellable = true, remap = false)
+    private void rivencraft$allowAuthoredAge(String path, CallbackInfoReturnable<Boolean> result) {
+        if (RuinsCompatibility.isKnownAge(dimension)) {
+            result.setReturnValue(RuinsCompatibility.allowsAge(dimension));
+        }
+    }
+
+    @Inject(method = "getTemplate", at = @At("HEAD"), cancellable = true, remap = false)
+    private void rivencraft$selectAuthoredTemplate(RandomSource random, String biome,
+                                                    CallbackInfoReturnable<Object> result) {
+        if (RuinsCompatibility.isKnownAge(dimension)) {
+            result.setReturnValue(RuinsEventAdapter.chooseTemplate(dimension, templates.get(biome), random));
+        }
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/mixin/RuinsTemplateDimensionMixin.java

@@ -0,0 +1,27 @@
+package net.dnorberg.rivencraft.mixin;
+
+import net.dnorberg.rivencraft.compat.RuinsCompatibility;
+import net.dnorberg.rivencraft.compat.RuinsTemplatePages;
+import net.minecraft.resources.Identifier;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Pseudo;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+/** An authored Ruins page overrides a template's vanilla-only dimension list for that Age. */
+@Pseudo
+@Mixin(targets = "atomicstryker.ruins.common.RuinTemplate", remap = false)
+public abstract class RuinsTemplateDimensionMixin {
+    @Shadow @Final private String name;
+
+    @Inject(method = "acceptsDimension", at = @At("HEAD"), cancellable = true, remap = false)
+    private void rivencraft$allowAuthoredAge(String dimensionPath, CallbackInfoReturnable<Boolean> result) {
+        Identifier dimension = Identifier.fromNamespaceAndPath("rivencraft", dimensionPath);
+        if (RuinsCompatibility.isKnownAge(dimension)) {
+            result.setReturnValue(RuinsCompatibility.permits(dimension, RuinsTemplatePages.featureId(name)));
+        }
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/network/PortBookNetworking.java

@@ -33,12 +33,19 @@ public final class PortBookNetworking {
 
     public static void registerPayloads(RegisterPayloadHandlersEvent event) {
         var registrar = event.registrar("1");
+        registrar.playToServer(SetLinkModifierSeedPayload.TYPE, SetLinkModifierSeedPayload.STREAM_CODEC,
+                (payload, context) -> {
+                    if (context.player() instanceof ServerPlayer player
+                            && player.containerMenu instanceof net.dnorberg.rivencraft.menu.LinkModifierMenu menu
+                            && menu.containerId == payload.containerId()) menu.setSeed(player, payload.age(), payload.seed());
+                });
         registrar.playToServer(SetLinkModifierTitlePayload.TYPE, SetLinkModifierTitlePayload.STREAM_CODEC,
                 (payload, context) -> {
                     if (context.player() instanceof ServerPlayer player
                             && player.containerMenu instanceof net.dnorberg.rivencraft.menu.LinkModifierMenu menu
                             && menu.containerId == payload.containerId()) menu.setTitle(player, payload.title());
                 });
+        registrar.playToClient(SereneAgeWhitelistPayload.TYPE, SereneAgeWhitelistPayload.STREAM_CODEC);
         registrar.playToClient(WritingDeskCatalogPayload.TYPE, WritingDeskCatalogPayload.STREAM_CODEC);
         registrar.playToServer(BindLinkingBookPayload.TYPE, BindLinkingBookPayload.STREAM_CODEC,
                 (payload, context) -> {
@@ -159,7 +166,7 @@ public final class PortBookNetworking {
             var environment = net.dnorberg.rivencraft.age.PortEnvironmentSelection.resolve(activePages, seed, terrain);
             var randomFeatures = pages.isEmpty()
                     ? net.dnorberg.rivencraft.age.PortRandomFeatureSelection.select(server, seed, terrain, biomePlan) : null;
-            var level = RuntimeAgeBackend.create(server, id, seed, biomePlan, terrain,
+            RuntimeAgeBackend.create(server, id, seed, biomePlan, terrain,
                     randomFeatures == null ? PortAuthoredWriting.rockPlan(generationPages, seed) : randomFeatures.rocks(),
                     PortAuthoredWriting.vegetationPlan(generationPages),
                     randomFeatures == null ? PortAuthoredWriting.dungeonCount(generationPages) : randomFeatures.dungeons(),
@@ -168,12 +175,11 @@ public final class PortBookNetworking {
                     environment.weather(), environment.lighting(), environment.sky(),
                     net.dnorberg.rivencraft.age.PortAgeColors.resolve(pages, seed),
                     net.dnorberg.rivencraft.age.PortDayCycle.resolve(pages, seed,
-                            net.dnorberg.rivencraft.age.PortDayCycle.nativeTicks(server.overworld())), pages);
-            net.dnorberg.rivencraft.age.PortAcceleratedTicks.configure(level,
-                    net.dnorberg.rivencraft.age.PortAcceleratedTicks.pageCount(pages));
-            RuntimeAgeBackend.setAgeDisplayName(server, id, title);
-        } catch (IllegalArgumentException | IllegalStateException exception) {
-            player.sendOverlayMessage(Component.literal("Age creation failed: " + exception.getMessage()));
+                            net.dnorberg.rivencraft.age.PortDayCycle.nativeTicks(server.overworld())), pages, title);
+        } catch (RuntimeException exception) {
+            Rivencraft.LOGGER.warn("Age creation failed for {}", id, exception);
+            player.sendOverlayMessage(Component.literal("Age creation failed: "
+                    + java.util.Objects.toString(exception.getMessage(), "internal error")));
             return null;
         }
         return id;

ports/mc263/src/main/java/net/dnorberg/rivencraft/network/SereneAgeWhitelistPayload.java

@@ -0,0 +1,25 @@
+package net.dnorberg.rivencraft.network;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.Identifier;
+
+/** Updates an already connected client's Serene whitelist for one Age. */
+public record SereneAgeWhitelistPayload(Identifier dimensionId, boolean enabled) implements CustomPacketPayload {
+    public static final Type<SereneAgeWhitelistPayload> TYPE = new Type<>(
+            Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "serene_age_whitelist"));
+    public static final StreamCodec<RegistryFriendlyByteBuf, SereneAgeWhitelistPayload> STREAM_CODEC =
+            StreamCodec.of(
+                    (buffer, payload) -> {
+                        buffer.writeIdentifier(payload.dimensionId());
+                        buffer.writeBoolean(payload.enabled());
+                    },
+                    buffer -> new SereneAgeWhitelistPayload(buffer.readIdentifier(), buffer.readBoolean()));
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/network/SetLinkModifierSeedPayload.java

@@ -0,0 +1,19 @@
+package net.dnorberg.rivencraft.network;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.Identifier;
+
+public record SetLinkModifierSeedPayload(int containerId, Identifier age, String seed) implements CustomPacketPayload {
+    public static final Type<SetLinkModifierSeedPayload> TYPE = new Type<>(
+            Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "set_link_modifier_seed"));
+    public static final StreamCodec<RegistryFriendlyByteBuf, SetLinkModifierSeedPayload> STREAM_CODEC =
+            StreamCodec.composite(ByteBufCodecs.VAR_INT, SetLinkModifierSeedPayload::containerId,
+                    Identifier.STREAM_CODEC, SetLinkModifierSeedPayload::age,
+                    ByteBufCodecs.stringUtf8(21), SetLinkModifierSeedPayload::seed,
+                    SetLinkModifierSeedPayload::new);
+    @Override public Type<SetLinkModifierSeedPayload> type() { return TYPE; }
+}

ports/mc263/src/main/java/net/dnorberg/rivencraft/registry/ModCreativeTabs.java

@@ -2,7 +2,6 @@ package net.dnorberg.rivencraft.registry;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.item.PageItem;
-import net.dnorberg.rivencraft.item.LinkProperties;
 import net.dnorberg.rivencraft.writing.PortSymbolPages;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.chat.Component;
@@ -45,14 +44,7 @@ public final class ModCreativeTabs {
                 .title(Component.translatable("itemGroup.rivencraft.pages.link"))
                 .icon(PageItem::createLinkPanelPage)
                 .displayItems((parameters, output) -> {
-                    int[] flags = {LinkProperties.DISARM, LinkProperties.MAINTAIN_MOMENTUM,
-                            LinkProperties.INTRA_LINKING};
-                    for (int combination = 0; combination < 8; combination++) {
-                        int selected = 0;
-                        for (int bit = 0; bit < flags.length; bit++)
-                            if ((combination & (1 << bit)) != 0) selected |= flags[bit];
-                        output.accept(PageItem.createLinkPanelPage(selected));
-                    }
+                    PageItem.creativeLinkPanelPages().forEach(output::accept);
                 })
                 .build());
         for (String category : PortSymbolPages.categories()) {

ports/mc263/src/main/java/net/dnorberg/rivencraft/writing/PortAuthoredWriting.java

@@ -55,6 +55,9 @@ public final class PortAuthoredWriting {
         if (page == null || !page.getNamespace().equals(Rivencraft.MOD_ID)) return false;
         var entry = PortSymbolPages.find(page);
         if (entry == null) return false;
+        var season = net.dnorberg.rivencraft.age.PortSeasonPolicies.forPage(page);
+        if (season != null) return season == net.dnorberg.rivencraft.age.PortSeasonPolicies.Mode.NO_SEASONS
+                || net.dnorberg.rivencraft.compat.SereneSeasonsCompatibility.available();
         if (net.dnorberg.rivencraft.age.PortAgeColors.isModifier(page)
                 || net.dnorberg.rivencraft.age.PortDayCycle.supports(page)) return true;
         if (page.equals(net.dnorberg.rivencraft.age.PortAcceleratedTicks.PAGE)
@@ -69,7 +72,8 @@ public final class PortAuthoredWriting {
                 || page.equals(PortTerrainFeaturePlan.SKYLANDS)
                 || page.equals(PortTerrainFeaturePlan.DENSE_ORES)
                 || page.equals(PortTerrainFeaturePlan.STAR_FISSURES)
-                || PortStructurePages.supports(page) || PortCarverPages.supports(page);
+                || PortStructurePages.supports(page) || PortCarverPages.supports(page)
+                || net.dnorberg.rivencraft.compat.RuinsTemplatePages.contains(page);
     }
 
     /** Recover known category defects; unimplemented pages and unsupported runtime combinations still block binding. */
@@ -121,7 +125,7 @@ public final class PortAuthoredWriting {
         int skylands = 0;
         int denseOres = 0;
         int starFissures = 0;
-        int weather = 0;
+        int weather = 0, season = 0;
         int lighting = 0;
         int sky = 0;
         Map<Identifier, Integer> terrainFeatures = new HashMap<>();
@@ -140,6 +144,8 @@ public final class PortAuthoredWriting {
                 // Every Accelerated page adds random-tick attempts; it is not a controller.
             } else if (isTerrain(page) && !terrain) {
                 terrain = true;
+            } else if (net.dnorberg.rivencraft.age.PortSeasonPolicies.forPage(page) != null && season++ == 0) {
+                // Per-Age optional season policy, independent of ordinary weather.
             } else if (PortSkyStyle.forPage(page) != null && sky++ == 0) {
                 // Sky presentation, independent of terrain and illumination.
             } else if (PortLighting.forPage(page) != null && lighting++ == 0) {
@@ -178,6 +184,8 @@ public final class PortAuthoredWriting {
             } else if (PortStructurePages.supports(page)
                     && structures.getOrDefault(page, 0) < PortTerrainFeaturePlan.MAX_PER_FEATURE) {
                 structures.merge(page, 1, Integer::sum);
+            } else if (net.dnorberg.rivencraft.compat.RuinsTemplatePages.contains(page)) {
+                // Each exact template page is retained, including copies beyond the attempt cap.
             } else if (PortVegetationPlan.isVegetation(page) && vegetation < MAX_VEGETATION) {
                 vegetation++;
             } else if (page.equals(DUNGEONS) && dungeons < MAX_DUNGEONS) {
@@ -281,8 +289,10 @@ public final class PortAuthoredWriting {
         boolean starFissures = pages.contains(PortTerrainFeaturePlan.STAR_FISSURES);
         List<Identifier> structures = pages.stream().filter(PortStructurePages::supports).toList();
         List<Identifier> carvers = pages.stream().filter(PortCarverPages::supports).toList();
-        return choices.isEmpty() && !skylands && denseOres == 0 && !starFissures && structures.isEmpty() && carvers.isEmpty() ? null
-                : new PortTerrainFeaturePlan(choices, skylands, denseOres, starFissures, structures, carvers);
+        List<Identifier> ruins = pages.stream().filter(net.dnorberg.rivencraft.compat.RuinsTemplatePages::contains).toList();
+        return choices.isEmpty() && !skylands && denseOres == 0 && !starFissures && structures.isEmpty()
+                && carvers.isEmpty() && ruins.isEmpty() ? null
+                : new PortTerrainFeaturePlan(choices, skylands, denseOres, starFissures, structures, carvers, false, ruins);
     }
 
     private static List<Identifier> solidMaterials(List<Identifier> pages, long seed, Identifier feature) {
@@ -373,6 +383,7 @@ public final class PortAuthoredWriting {
         PortStructurePages.validateRegistry(pages, registries);
         PortCarverPages.validateRegistry(pages, registries);
         PortBiomePlan.Distribution distribution = null;
+        net.dnorberg.rivencraft.compat.TerraBlenderBiomes.nether(registries);
         boolean caveTerrain = pages.contains(CAVE_TERRAIN);
         boolean hasSurfaceBiome = false;
         boolean hasOreBiome = false;

ports/mc263/src/main/java/net/dnorberg/rivencraft/writing/PortMaterialCompletion.java

@@ -51,7 +51,8 @@ public final class PortMaterialCompletion {
     }
 
     private static boolean isFeature(Identifier page) {
-        return PortTerrainFeaturePlan.isSupported(page) || PortLakePlan.isLake(page)
+        return net.dnorberg.rivencraft.compat.RuinsTemplatePages.contains(page)
+                || PortTerrainFeaturePlan.isSupported(page) || PortLakePlan.isLake(page)
                 || PortVegetationPlan.isVegetation(page) || PortStructurePages.supports(page)
                 || PortCarverPages.supports(page) || page.equals(id("feature/rocks"))
                 || page.equals(id("feature/dungeons")) || page.equals(PortTerrainFeaturePlan.SKYLANDS)

ports/mc263/src/main/java/net/dnorberg/rivencraft/writing/PortRegistryPages.java

@@ -22,7 +22,7 @@ import net.minecraft.world.level.block.EntityBlock;
 public final class PortRegistryPages {
     private static final TagKey<net.minecraft.world.level.biome.Biome> CAVE_BIOMES = TagKey.create(
             Registries.BIOME, Identifier.fromNamespaceAndPath(Rivencraft.MOD_ID, "cave_biomes"));
-    private static final Identifier DEFERRED_PLACEHOLDER = Identifier.fromNamespaceAndPath(
+    public static final Identifier DEFERRED_PLACEHOLDER = Identifier.fromNamespaceAndPath(
             "terrablender", "deferred_placeholder");
 
     private PortRegistryPages() {}
@@ -65,6 +65,7 @@ public final class PortRegistryPages {
     }
 
     public static List<ItemStack> biomePages(HolderLookup.Provider registries, boolean caves) {
+        net.dnorberg.rivencraft.compat.TerraBlenderBiomes.nether(registries);
         return registries.lookupOrThrow(Registries.BIOME).listElements()
                 .filter(holder -> !holder.key().identifier().equals(DEFERRED_PLACEHOLDER))
                 .filter(holder -> isCaveBiome(holder) == caves)
@@ -98,6 +99,7 @@ public final class PortRegistryPages {
     public static boolean isCaveBiome(net.minecraft.core.Holder<net.minecraft.world.level.biome.Biome> holder) {
         String path = holder.unwrapKey().map(key -> key.identifier().getPath()).orElse("");
         return holder.is(CAVE_BIOMES) || holder.is(BiomeTags.IS_NETHER)
+                || net.dnorberg.rivencraft.compat.TerraBlenderBiomes.isNether(holder)
                 || path.equals("deep_dark") || path.endsWith("_caves");
     }
 

ports/mc263/src/main/java/net/dnorberg/rivencraft/writing/PortSymbolPages.java

@@ -31,7 +31,9 @@ public final class PortSymbolPages {
 
     public static Entry find(Identifier id) {
         Entry bundled = ENTRIES.get(id);
-        return bundled != null ? bundled : PortRegistryPages.find(id);
+        if (bundled != null) return bundled;
+        var ruin = net.dnorberg.rivencraft.compat.RuinsTemplatePages.find(id);
+        return ruin != null ? ruin : PortRegistryPages.find(id);
     }
 
     public static List<String> categories() {
@@ -40,6 +42,7 @@ public final class PortSymbolPages {
         categories.add("rivencraft:cave_biome");
         categories.add("rivencraft:block");
         categories.add("rivencraft:fluid");
+        if (!net.dnorberg.rivencraft.compat.RuinsTemplatePages.templates().isEmpty()) categories.add("rivencraft:ruins");
         return List.copyOf(categories);
     }
 
@@ -58,6 +61,9 @@ public final class PortSymbolPages {
                 .filter(entry -> !category.equals("rivencraft:biome")
                         || !entry.id().getPath().startsWith("biome/"))
                 .forEach(entry -> pages.add(PageItem.createSymbolPage(entry.id())));
+        if (category.equals("rivencraft:ruins")) net.dnorberg.rivencraft.compat.RuinsTemplatePages.templates()
+                .forEach(name -> pages.add(PageItem.createSymbolPage(
+                        net.dnorberg.rivencraft.compat.RuinsTemplatePages.symbolId(name))));
         if (category.equals("rivencraft:biome")) pages.addAll(PortRegistryPages.biomePages(registries, false));
         if (category.equals("rivencraft:cave_biome")) pages.addAll(PortRegistryPages.biomePages(registries, true));
         if (category.equals("rivencraft:block")) pages.addAll(PortRegistryPages.materialPages(false));
@@ -66,6 +72,10 @@ public final class PortSymbolPages {
     }
 
     public static ItemStack icon(String category) {
+        if (category.equals("rivencraft:ruins")) return net.dnorberg.rivencraft.compat.RuinsTemplatePages.templates()
+                .stream().findFirst().map(name -> PageItem.createSymbolPage(
+                        net.dnorberg.rivencraft.compat.RuinsTemplatePages.symbolId(name)))
+                .orElseGet(PageItem::createLinkPanelPage);
         if (category.equals("rivencraft:cave_biome"))
             return PageItem.createSymbolPage(PortRegistryPages.biomePageId(
                     Identifier.fromNamespaceAndPath("minecraft", "lush_caves")));
@@ -79,6 +89,8 @@ public final class PortSymbolPages {
     }
 
     public static String fallbackName(Identifier id) {
+        if (net.dnorberg.rivencraft.compat.RuinsTemplatePages.isSymbol(id))
+            return net.dnorberg.rivencraft.compat.RuinsTemplatePages.fallbackName(id);
         if (id.getPath().startsWith("biome/") || id.getPath().startsWith("block/"))
             return PortRegistryPages.fallbackName(id);
         String path = id.getPath();

ports/mc263/src/main/resources/rivencraft.mixins.json

@@ -3,7 +3,22 @@
   "minVersion": "0.8",
   "package": "net.dnorberg.rivencraft.mixin",
   "compatibilityLevel": "JAVA_25",
-  "mixins": ["StructurePlacementAccessor", "AgeStructureBiomeMixin", "AgeCarversMixin", "AgeAmbientLightMixin", "AgeColorAttributesMixin", "AgeDayTimelineMixin"],
-  "client": ["StaticSkyStateMixin", "StaticSkyRendererMixin"],
-  "injectors": {"defaultRequire": 1}
+  "mixins": [
+    "StructurePlacementAccessor",
+    "AgeStructureBiomeMixin",
+    "AgeCarversMixin",
+    "AgeAmbientLightMixin",
+    "AgeColorAttributesMixin",
+    "AgeDayTimelineMixin",
+    "RuinsDimensionMixin",
+    "RuinsTemplateDimensionMixin",
+    "RuinsAttemptMixin"
+  ],
+  "client": [
+    "StaticSkyStateMixin",
+    "StaticSkyRendererMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
 }