Update optional Serene Seasons compatibility to 10.1.0.9

docs/LEGACY_M7_AUDIT.md

@@ -46,7 +46,7 @@ For a manual check, create a fresh surface Age and run `/rivencraft library near
 
 Issue #75's comment calls this a despawning drop. The code differs subtly: [`EntityLinkbook`](https://github.com/Mystcraft/Mystcraft-Legacy/blob/9bc8ddc061845df0cd5ea47f4fdef773cff786ae/src/main/java/com/xcompwiz/mystcraft/entity/EntityLinkbook.java#L190-L224) explicitly cannot despawn, but takes one starvation damage every 10,000 ticks and damage while wet. It can eventually be destroyed if left unattended; a vanilla item entity's fixed five-minute timeout is not parity. A modern equivalent should retain the visible book and avoid silently deleting its Age identity at that timeout.
 
-Legacy's travel path creates no automatic Return Link. Rivencraft now defaults to `DISABLED` in new server configs while retaining `ON_CREATION` and `ALWAYS` as opt-ins. Existing saved server configs keep their explicit value. Handheld-book drop is tracked in [#85](https://truenas-scale.tail180fb1.ts.net:8443/dnorberg/rivencraft/issues/85), not portal-frame logic.
+Legacy's travel path creates no automatic Return Link. Rivencraft now defaults to `DISABLED` in new server configs while retaining `ON_CREATION` and `ALWAYS` as opt-ins. Existing saved server configs keep their explicit value. Issue #85 adds the active-book drop only to hand-held Linking and Descriptive Book travel. On a successful link, the exact active stack becomes a dedicated `DroppedBookEntity` at the departure point, rendered with the same open `BookModel` and textures as the book stand; a rejected link restores it to the original hand. Stand and portal use leave their books in place. The entity has unlimited vanilla lifetime and loses one of its five item-health points every 10,000 loaded ticks, plus one per wet tick, matching Legacy's slow/wet decay. Unlike Legacy's custom entity, the modern book is picked up by ordinary contact, not sneaking with an empty hand, and remains subject to ordinary item hazards. Following is not yet a Rivencraft modifier, so no Following exception is exposed or silently simulated. Both hands can activate a book, whereas Legacy's explicit stack removal tested only its selected main-hand slot.
 
 ## Crafting, sounds, and progression
 

docs/MILESTONE_7_COMPATIBILITY_REVIEW.md

@@ -26,12 +26,12 @@ release V0.6.6.0.
 | --- | --- | --- | --- |
 | Dynamic Dimensions AR Edition (required) | 0.9.1 | 0.9.1 | No newer release found on [CurseForge](https://www.curseforge.com/minecraft/mc-mods/dynamicdimension-ar-edition/files/all). |
 | Bad Packets (required) | neo-0.8.2 | neo-0.8.2 | No newer matching [Modrinth](https://modrinth.com/mod/badpackets/versions) release found. |
-| JEI (optional) | 19.57.0.449 | 19.64.0.455 | Separate update issue; verify recipe categories and GUI discovery. |
+| JEI (optional) | 19.57.0.449 at #82 review | 19.69.0.457 beta | Updated in #86 after client and dedicated GameTest passes; see [JEI review](MILESTONE_7_JEI_REVIEW.md). |
 | Create (optional) | 6.0.10 | 6.0.10 | No newer matching [Modrinth](https://modrinth.com/mod/create/versions) release found. Its jar bundles Ponder 1.0.82. |
 | Ponder (bundled with Create) | 1.0.82 | 1.0.87 library artifact | [Maven](https://maven.createmod.net/net/createmod/ponder/ponder-neoforge/maven-metadata.xml) has a newer artifact, but Create 6.0.10 still bundles 1.0.82. Do not treat this as a separately installed Create update. |
 | Immersive Portals (optional) | 6.0.7 | 6.0.7 | No newer matching [Modrinth](https://modrinth.com/mod/immersive-portals-neoforge/versions) release found. |
 | TerraBlender (optional) | 4.1.0.8 | 4.1.0.8 | No newer matching [Modrinth](https://modrinth.com/mod/terrablender/versions) release found. |
-| Serene Seasons (optional) | 10.1.0.8 compile target | 10.1.0.9 | Separate update issue; the user's Prism instance already contains 10.1.0.9, but that is not a recorded compatibility pass. |
+| Serene Seasons (optional) | 10.1.0.8 at #82 review | 10.1.0.9 | Updated in #88 after the player's full seasonal matrix passed; see [Serene review](MILESTONE_7_SERENE_REVIEW.md). |
 | GlitchCore (Serene dependency) | 2.1.0.2 | 2.1.0.2 | No newer matching [Modrinth](https://modrinth.com/mod/glitchcore/versions) release found. |
 | Biomes O' Plenty (TerraBlender test addon) | 21.1.0.14 in user's Prism instance | 21.1.0.14 | No newer matching [Modrinth](https://modrinth.com/mod/biomes-o-plenty/versions) release found. |
 

docs/MILESTONE_7_JEI_REVIEW.md

@@ -0,0 +1,41 @@
+# JEI compatibility review (#86)
+
+Reviewed 2026-10-20 for Minecraft 1.21.1 and NeoForge 21.1.264. Rivencraft
+now targets JEI 19.69.0.457 after the client's in-game acceptance check. JEI
+remains a `compileOnly` API and an opt-in
+`localRuntime` dependency for development; the published mod has no required
+JEI dependency.
+
+The [official 1.21.1 NeoForge files](https://www.curseforge.com/minecraft/mc-mods/jei/files/all?page=1&pageSize=20&version=1.21.1)
+list 19.69.0.457 (beta, 2026-10-20) after 19.64.0.455 (release, 2026-10-16).
+The [19.69.0.457 Modrinth changelog](https://modrinth.com/mod/jei/versions?g=1.21.1&l=neoforge)
+has a published-jar bytecode compatibility check. Its preceding 19.69.0.456
+build changes ingredient search to Lucene and adds a runtime ingredient-search
+refresh API. This makes page search a required client check, even though the
+current Rivencraft plugin still compiles against the 457 API. The new Maven
+runtime artifact is much larger (about 7 MB versus 2.3 MB for 455); a successful
+compile alone is not evidence that its runtime plugin works.
+
+Checks performed before changing the pinned dependency:
+
+| Configuration | Result |
+| --- | --- |
+| `./gradlew -Pjei_version=19.69.0.457 -PwithJei=true build` | Passed; existing JEI API uses compile with four deprecation warnings and no errors. |
+| `./gradlew -Pjei_version=19.69.0.457 -PwithJei=true runGameTestServer` | Passed; dedicated GameTest server loaded JEI 19.69.0.457 and all 74 required tests passed. |
+| `./gradlew -Pjei_version=19.69.0.457 runGameTestServer` | Passed without JEI; all 74 required tests passed. |
+| Prism client with JEI 19.69.0.457 and Rivencraft 0.6.6.6 | Client joined an integrated world; JEI registered Rivencraft extra ingredients and started without a JEI-plugin exception. The player reported an in-game pass for guide display, page search, and recipe visibility. |
+
+On first 457 launch, JEI migrated its old `lowMemorySlowSearchEnabled` config
+key and saved a backup of the original `jei-client.ini`; that warning was
+handled by JEI and did not block startup. No Rivencraft config was changed.
+
+The in-game acceptance report covers the visible JEI integration. A dedicated
+GameTest server proves no server-side startup failure but does not exercise the
+JEI GUI; keep page search, recipes, blank-Page hiding, and the Ink Mixer,
+Writing Desk, and Book Binder guides in future upgrade checks. JEI is not
+bundled into or required by the published Rivencraft jar.
+
+The final pinned `0.6.6.7` build passed. A repeat GameTest run from the pinned
+configuration stalled during test-world preparation before running any cases;
+it was stopped. The two successful pre-pin runs above used the same JEI version
+and code, with the dependency supplied by a Gradle property override.

docs/MILESTONE_7_SERENE_REVIEW.md

@@ -0,0 +1,31 @@
+# Serene Seasons 10.1.0.9 compatibility review (#88)
+
+Reviewed 2026-10-20 for Minecraft 1.21.1 and NeoForge 21.1.264. Rivencraft
+now compiles against [Serene Seasons 10.1.0.9](https://modrinth.com/mod/serene-seasons/version/pHEgQQUE)
+with [GlitchCore 2.1.0.2](https://modrinth.com/mod/glitchcore/version/S2TfWrZR).
+Both remain optional. The Serene update fixes a precipitation-mixin recursion;
+it does not introduce a new dynamic-dimension API.
+
+The 10.1.0.8 and 10.1.0.9 bytecode for Rivencraft's version-sensitive
+`SeasonsConfig`, `SeasonHandler`, `SeasonSavedData`, and `SeasonTime` integration
+classes is identical. In particular, the dimension whitelist field, per-level
+saved season clock, and season update method have unchanged signatures and
+implementations. The adapter still writes the whitelist through GlitchCore's
+config API and sends Rivencraft's whitelist update to already connected clients.
+
+Verification:
+
+| Check | Result |
+| --- | --- |
+| Build against 10.1.0.9 and GlitchCore 2.1.0.2 | Passed. |
+| Real Prism client with Serene 10.1.0.9, GlitchCore 2.1.0.2, and Rivencraft 0.6.6.7 | Both mods loaded and the player joined an Age. |
+| No Seasons, normal Seasons, and all four Eternal modes in new and saved Ages | Player reported the full in-game matrix passed. |
+| Reconnect, restart, and Overworld independence | Player reported the full in-game matrix passed. |
+| Isolated dedicated-server startup without Serene/GlitchCore | Reached `Done` on port 25568 with only required runtime mods, then saved and stopped. |
+| Isolated dedicated-server startup with Serene/GlitchCore | Reached `Done` on port 25569 with 10.1.0.9/2.1.0.2, then saved and stopped. |
+
+Serene's sync packet is incompatible with GameTest mock players, so its
+in-game behavior must be checked with a real client and server. The seasonal
+test path in [SERENE_SEASONS_COMPATIBILITY.md](SERENE_SEASONS_COMPATIBILITY.md)
+remains the regression checklist for future upgrades. Rivencraft does not
+bundle or require Serene Seasons or GlitchCore.

gradle.properties

@@ -22,7 +22,7 @@ neo_version=21.1.264
 ponder_version=1.0.82
 dynamic_dimensions_file_id=7707789
 badpackets_version=0.8.2
-jei_version=19.57.0.449
+jei_version=19.69.0.457
 # The loader version range can only use the major version of FML as bounds
 loader_version_range=[1,)
 
@@ -36,10 +36,10 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. Rivencraft uses the x.y.z.b policy documented in README.md.
-mod_version=0.6.6.2
+mod_version=0.6.6.8
 immersive_portals_version=6.0.7
 terrablender_version=4.1.0.8
-serene_seasons_version_id=B6nTjh4b
+serene_seasons_version_id=pHEgQQUE
 glitchcore_version_id=S2TfWrZR
 # The group ID for the mod. It is only important when publishing as an artifact to a Maven repository.
 # This should match the base package used for the mod sources.

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

@@ -54,6 +54,7 @@ public final class Rivencraft {
         ModBiomeSources.register(modEventBus);
         ModChunkGenerators.register(modEventBus);
         ModBlocks.register(modEventBus);
+        net.dnorberg.rivencraft.registry.ModEntities.register(modEventBus);
         ModBlockEntities.register(modEventBus);
         ModItems.register(modEventBus);
         ModMenus.register(modEventBus);

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

@@ -0,0 +1,127 @@
+package net.dnorberg.rivencraft.book;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.entity.DroppedBookEntity;
+import net.dnorberg.rivencraft.registry.ModEntities;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.GlobalPos;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.entity.item.ItemEntity;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.phys.AABB;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class HandheldBookTravelGameTests {
+    private HandheldBookTravelGameTests() {
+    }
+
+    @GameTest(template = "empty")
+    public static void successfulHandheldTravelLeavesOnlyActiveBookAtOrigin(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        ItemStack book = new ItemStack(ModItems.LINKING_BOOK.get());
+        player.setItemInHand(InteractionHand.MAIN_HAND, book);
+        player.getInventory().setItem(1, new ItemStack(Items.DIAMOND));
+        var source = player.position();
+        BlockPos destination = helper.absolutePos(new BlockPos(2, 1, 2));
+        helper.getLevel().setBlock(destination, Blocks.AIR.defaultBlockState(), 2);
+        helper.getLevel().setBlock(destination.above(), Blocks.AIR.defaultBlockState(), 2);
+        LinkTarget target = new LinkTarget(GlobalPos.of(helper.getLevel().dimension(), destination), 0, 0);
+
+        helper.assertValueEqual(LinkingService.travelHandheld(player, InteractionHand.MAIN_HAND, book, target,
+                        new LinkProperties(LinkProperties.INTRA_LINKING), false), LinkingService.LinkResult.SUCCESS,
+                "A valid intra-dimensional handheld link must succeed");
+        helper.assertTrue(player.getMainHandItem().isEmpty(), "Only the active book must leave the hand");
+        helper.assertTrue(player.getInventory().getItem(1).is(Items.DIAMOND),
+                "An unrelated inventory item must remain with the player");
+        var drops = helper.getLevel().getEntitiesOfClass(DroppedBookEntity.class, new AABB(source, source).inflate(2.0),
+                entity -> entity.getItem().is(ModItems.LINKING_BOOK.get()));
+        helper.assertValueEqual(drops.size(), 1, "Exactly one recoverable book must remain at the departure point");
+        helper.assertTrue(drops.getFirst().getItem() == book,
+                "The model-rendered entity must retain the exact active book stack");
+        helper.assertTrue(drops.getFirst().copy() instanceof DroppedBookEntity,
+                "The pickup-animation copy must keep the custom renderer's entity type");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void rejectedHandheldTravelKeepsBook(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        ItemStack book = new ItemStack(ModItems.LINKING_BOOK.get());
+        player.setItemInHand(InteractionHand.OFF_HAND, book);
+        LinkTarget target = new LinkTarget(GlobalPos.of(helper.getLevel().dimension(), player.blockPosition()), 0, 0);
+
+        helper.assertValueEqual(LinkingService.travelHandheld(player, InteractionHand.OFF_HAND, book, target,
+                        LinkProperties.NONE, false), LinkingService.LinkResult.INTRA_LINKING_REQUIRED,
+                "A same-dimension link without Intra Linking must be rejected");
+        helper.assertTrue(player.getOffhandItem() == book, "The exact rejected book must be restored to its hand");
+        helper.assertTrue(helper.getLevel().getEntitiesOfClass(ItemEntity.class,
+                new AABB(player.position(), player.position()).inflate(2.0),
+                entity -> entity.getItem().is(ModItems.LINKING_BOOK.get())).isEmpty(),
+                "A rejected link must not leave a second copy at the origin");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void disarmDropsOtherInventoryWithoutDuplicatingActiveBook(GameTestHelper helper) {
+        var player = helper.makeMockServerPlayerInLevel();
+        ItemStack book = new ItemStack(ModItems.LINKING_BOOK.get());
+        player.setItemInHand(InteractionHand.MAIN_HAND, book);
+        player.getInventory().setItem(1, new ItemStack(Items.DIAMOND));
+        var source = player.position();
+        BlockPos destination = helper.absolutePos(new BlockPos(2, 1, 2));
+        helper.getLevel().setBlock(destination, Blocks.AIR.defaultBlockState(), 2);
+        helper.getLevel().setBlock(destination.above(), Blocks.AIR.defaultBlockState(), 2);
+        LinkTarget target = new LinkTarget(GlobalPos.of(helper.getLevel().dimension(), destination), 0, 0);
+
+        helper.assertValueEqual(LinkingService.travelHandheld(player, InteractionHand.MAIN_HAND, book, target,
+                        new LinkProperties(LinkProperties.INTRA_LINKING | LinkProperties.DISARM), false),
+                LinkingService.LinkResult.SUCCESS, "Disarm must not block handheld travel");
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(source, source).inflate(2.0));
+        helper.assertValueEqual(drops.stream().filter(entity -> entity instanceof DroppedBookEntity).count(),
+                1L, "Disarm must not create a second copy of the active book");
+        helper.assertValueEqual(drops.stream().filter(entity -> entity.getItem().is(Items.DIAMOND)).count(),
+                1L, "Disarm must still drop unrelated inventory items");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void originBookUsesSlowDecayWithoutVanillaDespawn(GameTestHelper helper) {
+        DroppedBookEntity book = new DroppedBookEntity(helper.getLevel(),
+                net.minecraft.world.phys.Vec3.ZERO, new ItemStack(ModItems.LINKING_BOOK.get()));
+        CompoundTag seeded = new CompoundTag();
+        book.saveWithoutId(seeded);
+        seeded.putInt("BookDecayTicks", 9_999);
+        book.readAdditionalSaveData(seeded);
+        book.tick();
+        CompoundTag saved = new CompoundTag();
+        book.saveWithoutId(saved);
+        helper.assertValueEqual(saved.getShort("Age"), (short)-32_768,
+                "The dropped book must not expire after vanilla's five minutes");
+        helper.assertValueEqual(saved.getShort("Health"), (short)4,
+                "A dropped book must lose one item-health point after 10,000 loaded ticks");
+        helper.assertValueEqual(saved.getInt("BookDecayTicks"), 0,
+                "Slow decay must reset its interval and persist across a restart");
+        DroppedBookEntity restored = new DroppedBookEntity(ModEntities.DROPPED_BOOK.get(), helper.getLevel());
+        restored.readAdditionalSaveData(saved);
+        CompoundTag resaved = new CompoundTag();
+        restored.saveWithoutId(resaved);
+        helper.assertTrue(restored.getItem().is(ModItems.LINKING_BOOK.get()),
+                "The custom book entity must retain its book on reload");
+        helper.assertValueEqual(resaved.getShort("Age"), (short)-32_768,
+                "The custom book must remain non-despawning after reload");
+        helper.assertValueEqual(resaved.getShort("Health"), (short)4,
+                "Decay damage must persist after reload");
+        helper.assertTrue(restored.copy().getItem().is(ModItems.LINKING_BOOK.get()),
+                "A pickup-animation copy must retain the book data after reload");
+        helper.succeed();
+    }
+}

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

@@ -5,10 +5,13 @@ import java.util.Optional;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 import net.dnorberg.rivencraft.compat.ImmersivePortalsChunkLoaders;
+import net.dnorberg.rivencraft.entity.DroppedBookEntity;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.tags.BlockTags;
 import net.minecraft.world.level.border.WorldBorder;
 import net.minecraft.world.level.levelgen.Heightmap;
@@ -32,6 +35,36 @@ public final class LinkingService {
         return travel(player, target, false, properties, false);
     }
 
+    /** Removes only the active handheld book after a successful link, leaving it at the departure point. */
+    public static LinkResult travelHandheld(ServerPlayer player, InteractionHand hand, ItemStack activeBook,
+                                            LinkTarget target, LinkProperties properties, boolean requiresFooting) {
+        if (player.getItemInHand(hand) != activeBook || activeBook.isEmpty()) {
+            return LinkResult.NO_SAFE_DESTINATION;
+        }
+
+        ServerLevel sourceLevel = player.serverLevel();
+        Vec3 sourcePosition = player.position();
+        player.setItemInHand(hand, ItemStack.EMPTY);
+        boolean dropped = false;
+        try {
+            LinkResult result = requiresFooting
+                    ? travelWithFooting(player, target, properties)
+                    : travel(player, target, properties);
+            if (result != LinkResult.SUCCESS) return result;
+
+            DroppedBookEntity book = new DroppedBookEntity(sourceLevel, sourcePosition, activeBook);
+            dropped = sourceLevel.addFreshEntity(book);
+            return result;
+        } finally {
+            // Failed validation or a rejected entity spawn must never eat the book.
+            if (!dropped) {
+                if (player.getItemInHand(hand).isEmpty()) player.setItemInHand(hand, activeBook);
+                else if (!player.getInventory().add(activeBook)) player.drop(activeBook, false);
+            }
+            player.containerMenu.broadcastChanges();
+        }
+    }
+
     /** Portal travel uses the vanilla transfer if its destination is not yet loaded. */
     public static LinkResult travelPortal(ServerPlayer player, LinkTarget target, LinkProperties properties) {
         return travel(player, target, false, properties, true);

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

@@ -5,6 +5,7 @@ import net.dnorberg.rivencraft.registry.ModBlockEntities;
 import net.dnorberg.rivencraft.registry.ModBlocks;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
 import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.registry.ModEntities;
 import net.minecraft.client.renderer.item.ItemProperties;
 import net.minecraft.client.renderer.ItemBlockRenderTypes;
 import net.minecraft.client.renderer.RenderType;
@@ -34,6 +35,7 @@ public final class ClientEvents {
 
     @SubscribeEvent
     public static void registerRenderers(EntityRenderersEvent.RegisterRenderers event) {
+        event.registerEntityRenderer(ModEntities.DROPPED_BOOK.get(), DroppedBookRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.BOOK_STAND.get(), BookStandRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.WRITING_DESK.get(), WritingDeskRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.STAR_FISSURE.get(), StarFissureRenderer::new);

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

@@ -0,0 +1,51 @@
+package net.dnorberg.rivencraft.client;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.VertexConsumer;
+import com.mojang.math.Axis;
+import net.dnorberg.rivencraft.entity.DroppedBookEntity;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.client.model.BookModel;
+import net.minecraft.client.model.geom.ModelLayers;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.entity.EntityRenderer;
+import net.minecraft.client.renderer.entity.EntityRendererProvider;
+import net.minecraft.resources.ResourceLocation;
+
+/** Renders the same open book model and textures as Rivencraft's book stands. */
+public final class DroppedBookRenderer extends EntityRenderer<DroppedBookEntity> {
+    private static final ResourceLocation LINKING_TEXTURE = ResourceLocation.fromNamespaceAndPath(
+            "rivencraft", "textures/entity/linking_book.png");
+    private static final ResourceLocation DESCRIPTIVE_TEXTURE = ResourceLocation.fromNamespaceAndPath(
+            "rivencraft", "textures/entity/descriptive_book.png");
+    private final BookModel model;
+
+    public DroppedBookRenderer(EntityRendererProvider.Context context) {
+        super(context);
+        model = new BookModel(context.bakeLayer(ModelLayers.BOOK));
+        shadowRadius = 0.25F;
+    }
+
+    @Override
+    public void render(DroppedBookEntity entity, float yaw, float partialTick, PoseStack poseStack,
+                       MultiBufferSource buffers, int packedLight) {
+        poseStack.pushPose();
+        poseStack.translate(0.0F, 0.0625F, 0.0F);
+        poseStack.mulPose(Axis.YP.rotationDegrees(yaw + 90.0F));
+        // The opened model's covers rotate toward the YZ plane. As in Legacy's
+        // dropped-book renderer, a Z-axis quarter-turn lays the pages skyward.
+        poseStack.mulPose(Axis.ZP.rotationDegrees(90.0F));
+        poseStack.scale(0.8F, 0.8F, 0.8F);
+        model.setupAnim(0.0F, 0.0F, 0.0F, 1.2F);
+        VertexConsumer vertices = buffers.getBuffer(RenderType.entitySolid(getTextureLocation(entity)));
+        model.render(poseStack, vertices, packedLight, net.minecraft.client.renderer.texture.OverlayTexture.NO_OVERLAY, -1);
+        poseStack.popPose();
+        super.render(entity, yaw, partialTick, poseStack, buffers, packedLight);
+    }
+
+    @Override
+    public ResourceLocation getTextureLocation(DroppedBookEntity entity) {
+        return entity.getItem().is(ModItems.DESCRIPTIVE_BOOK.get()) ? DESCRIPTIVE_TEXTURE : LINKING_TEXTURE;
+    }
+}

src/main/java/net/dnorberg/rivencraft/entity/DroppedBookEntity.java

@@ -0,0 +1,62 @@
+package net.dnorberg.rivencraft.entity;
+
+import net.dnorberg.rivencraft.registry.ModEntities;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.entity.item.ItemEntity;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.phys.Vec3;
+
+/** A recoverable, model-rendered book left behind by handheld linking. */
+public final class DroppedBookEntity extends ItemEntity {
+    private static final String DECAY_TICKS_TAG = "BookDecayTicks";
+    private static final int SLOW_DECAY_INTERVAL = 10_000;
+    private int decayTicks;
+
+    public DroppedBookEntity(EntityType<DroppedBookEntity> type, Level level) {
+        super(type, level);
+    }
+
+    public DroppedBookEntity(Level level, Vec3 position, ItemStack stack) {
+        this(ModEntities.DROPPED_BOOK.get(), level);
+        setPos(position.x, position.y + 0.25, position.z);
+        setDeltaMovement(Vec3.ZERO);
+        setItem(stack);
+        setUnlimitedLifetime();
+        setPickUpDelay(20);
+    }
+
+    /** Vanilla's pickup particle calls ItemEntity.copy() and renders the returned entity. */
+    @Override
+    public DroppedBookEntity copy() {
+        DroppedBookEntity copy = new DroppedBookEntity(ModEntities.DROPPED_BOOK.get(), level());
+        copy.copyPosition(this);
+        copy.setItem(getItem().copy());
+        copy.setUnlimitedLifetime();
+        return copy;
+    }
+
+    @Override
+    public void tick() {
+        super.tick();
+        if (level().isClientSide || isRemoved()) return;
+        if (++decayTicks >= SLOW_DECAY_INTERVAL) {
+            decayTicks = 0;
+            hurt(damageSources().starve(), 1.0F);
+        }
+        if (!isRemoved() && isInWaterOrRain()) hurt(damageSources().drown(), 1.0F);
+    }
+
+    @Override
+    public void addAdditionalSaveData(CompoundTag tag) {
+        super.addAdditionalSaveData(tag);
+        tag.putInt(DECAY_TICKS_TAG, decayTicks);
+    }
+
+    @Override
+    public void readAdditionalSaveData(CompoundTag tag) {
+        super.readAdditionalSaveData(tag);
+        decayTicks = Math.max(0, Math.min(tag.getInt(DECAY_TICKS_TAG), SLOW_DECAY_INTERVAL - 1));
+    }
+}

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

@@ -18,6 +18,7 @@ import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.MutableComponent;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.InteractionHand;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.TooltipFlag;
@@ -41,14 +42,18 @@ public final class DescriptiveBookItem extends Item {
     }
 
     public static boolean useWrittenBook(ServerPlayer player, ItemStack stack) {
-        return useWrittenBook(player, stack, false);
+        return useWrittenBook(player, stack, false, null);
+    }
+
+    public static boolean useHandheldBook(ServerPlayer player, InteractionHand hand) {
+        return useWrittenBook(player, player.getItemInHand(hand), false, hand);
     }
 
     public static boolean usePortalBook(ServerPlayer player, ItemStack stack) {
-        return useWrittenBook(player, stack, true);
+        return useWrittenBook(player, stack, true, null);
     }
 
-    private static boolean useWrittenBook(ServerPlayer player, ItemStack stack, boolean portal) {
+    private static boolean useWrittenBook(ServerPlayer player, ItemStack stack, boolean portal, InteractionHand hand) {
         AgeReference age = stack.get(ModDataComponents.AGE_REFERENCE.get());
         if (age == null) {
             player.displayClientMessage(Component.translatable("message.rivencraft.descriptive_book.unwritten"), true);
@@ -68,7 +73,8 @@ public final class DescriptiveBookItem extends Item {
                 .forDescriptiveBook();
         LinkingService.LinkResult result = portal
                 ? LinkingService.travelDescriptivePortal(player, ageTarget, properties)
-                : LinkingService.travelWithFooting(player, ageTarget, properties);
+                : hand == null ? LinkingService.travelWithFooting(player, ageTarget, properties)
+                : LinkingService.travelHandheld(player, hand, stack, ageTarget, properties, true);
         if (result != LinkingService.LinkResult.SUCCESS) {
             player.displayClientMessage(Component.translatable("message.rivencraft.descriptive_book.unsafe"), true);
             return false;

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

@@ -43,14 +43,19 @@ public final class LinkingBookItem extends Item {
     }
 
     public static InteractionResultHolder<ItemStack> useBoundBook(ServerPlayer player, ItemStack stack) {
-        return useBoundBook(player, stack, false);
+        return useBoundBook(player, stack, false, null);
+    }
+
+    public static InteractionResultHolder<ItemStack> useHandheldBook(ServerPlayer player, InteractionHand hand) {
+        return useBoundBook(player, player.getItemInHand(hand), false, hand);
     }
 
     public static InteractionResultHolder<ItemStack> usePortalBook(ServerPlayer player, ItemStack stack) {
-        return useBoundBook(player, stack, true);
+        return useBoundBook(player, stack, true, null);
     }
 
-    private static InteractionResultHolder<ItemStack> useBoundBook(ServerPlayer player, ItemStack stack, boolean portal) {
+    private static InteractionResultHolder<ItemStack> useBoundBook(ServerPlayer player, ItemStack stack, boolean portal,
+                                                                   InteractionHand hand) {
         LinkTarget target = stack.get(ModDataComponents.LINK_TARGET.get());
         if (target == null) {
             player.displayClientMessage(Component.translatable("message.rivencraft.linking_book.unbound"), true);
@@ -62,7 +67,8 @@ public final class LinkingBookItem extends Item {
         LinkProperties properties = stack.getOrDefault(ModDataComponents.LINK_PROPERTIES.get(), LinkProperties.NONE);
         LinkingService.LinkResult result = portal
                 ? LinkingService.travelPortal(player, target, properties)
-                : LinkingService.travel(player, target, properties);
+                : hand == null ? LinkingService.travel(player, target, properties)
+                : LinkingService.travelHandheld(player, hand, stack, target, properties, false);
         if (result == LinkingService.LinkResult.SUCCESS) {
             LinkVisualEffects.play(sourceLevel, sourcePosition, player, properties, portal);
             ProgressionAdvancements.awardAgeTravel(player);

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

@@ -211,7 +211,7 @@ public final class ModNetworking {
 
         ItemStack stack = player.getItemInHand(hand(payload.offhand()));
         if (stack.is(ModItems.LINKING_BOOK.get()) && stack.has(ModDataComponents.LINK_TARGET.get())) {
-            LinkingBookItem.useBoundBook(player, stack);
+            LinkingBookItem.useHandheldBook(player, hand(payload.offhand()));
         }
     }
 
@@ -245,7 +245,8 @@ public final class ModNetworking {
         }
 
         if (stack.is(ModItems.DESCRIPTIVE_BOOK.get())) {
-            DescriptiveBookItem.useWrittenBook(player, stack);
+            if (payload.fromStand()) DescriptiveBookItem.useWrittenBook(player, stack);
+            else DescriptiveBookItem.useHandheldBook(player, hand(payload.offhand()));
         }
     }
 

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

@@ -0,0 +1,30 @@
+package net.dnorberg.rivencraft.registry;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.entity.DroppedBookEntity;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.entity.MobCategory;
+import net.neoforged.bus.api.IEventBus;
+import net.neoforged.neoforge.registries.DeferredHolder;
+import net.neoforged.neoforge.registries.DeferredRegister;
+
+public final class ModEntities {
+    private static final DeferredRegister<EntityType<?>> ENTITIES =
+            DeferredRegister.create(Registries.ENTITY_TYPE, Rivencraft.MOD_ID);
+
+    public static final DeferredHolder<EntityType<?>, EntityType<DroppedBookEntity>> DROPPED_BOOK =
+            ENTITIES.register("dropped_book", () -> EntityType.Builder
+                    .<DroppedBookEntity>of(DroppedBookEntity::new, MobCategory.MISC)
+                    .sized(0.65F, 0.4F)
+                    .clientTrackingRange(10)
+                    .updateInterval(20)
+                    .build(Rivencraft.MOD_ID + ":dropped_book"));
+
+    private ModEntities() {
+    }
+
+    public static void register(IEventBus bus) {
+        ENTITIES.register(bus);
+    }
+}