diff --git a/.claude/settings.json b/.claude/settings.json
index 1112fd095..751b8ef20 100644
--- a/.claude/settings.json
+++ b/.claude/settings.json
@@ -1,4 +1,5 @@
 {
+  "worktree": { "bgIsolation": "none" },
   "hooks": {
     "SessionStart": [
       {
diff --git a/build.gradle.kts b/build.gradle.kts
index 9bf320bec..f1509856d 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,6 +1,8 @@
+import com.hypherionmc.modfusioner.plugin.FusionerExtension
 import net.fabricmc.loom.api.LoomGradleExtensionAPI
 import org.gradle.api.publish.PublishingExtension
 import org.gradle.api.publish.maven.MavenPublication
+import org.gradle.api.tasks.bundling.AbstractArchiveTask
 import org.jetbrains.kotlin.konan.properties.loadProperties
 
 plugins {
@@ -46,6 +48,10 @@ version = "mod_version".prop ?: "0.0.1-SNAPSHOT"
 group = "mod_group".prop ?: "net.kernelpanicsoft"
 
 subprojects {
+	// Stonecutter's tree/branch anchors (e.g. `:core`) are synthetic container projects with real
+	// leaf projects nested under them - they must not get build plugins applied to them directly.
+	if (subprojects.isNotEmpty()) return@subprojects
+
 	apply(plugin = "dev.architectury.loom")
 	apply(plugin = "net.kernelpanicsoft.actualizer")
 
@@ -115,12 +121,20 @@ subprojects {
 		})
 
 		compileOnly("org.jetbrains:annotations:24.1.0")
+
+		// Gradle 9 stopped bundling its own copy of the JUnit Platform launcher for
+		// useJUnitPlatform() - every module needs this on the test runtime classpath now.
+		"testRuntimeOnly"(rootProject.libs.junit.platform.launcher)
 	}
 
 	// One MavenPublication per module, published to kernelpanicsoft.net's Reposilite - archie-core/
 	// -datagen/-gametest are real consumable libraries; archie-test is a dev playground, never
 	// published (matches fusioner/dokka's own product/test split above).
-	if (!project.name.startsWith("archie-test-")) {
+	//
+	// Under Stonecutter, `project.name` is just the version segment ("1.21.1") for every leaf in
+	// every tree - it no longer distinguishes "test" from the rest. `project.path` still does
+	// (":test:common:1.21.1" etc.), since Stonecutter nests leaves under their tree name.
+	if (!project.path.startsWith(":test:")) {
 		// allprojects{} (below) is what normally applies these, but it's declared after this
 		// subprojects{} block and hasn't run for this project yet - apply is idempotent, so
 		// re-applying here just guarantees ordering for the components["java"]/publishing{} access
@@ -128,28 +142,35 @@ subprojects {
 		apply(plugin = "java")
 		apply(plugin = "maven-publish")
 
-		extensions.configure<PublishingExtension>("publishing") {
-			publications {
-				create<MavenPublication>("maven") {
-					artifactId = base.archivesName.get()
-					from(components["java"])
+		// base.archivesName only reaches its final "archie-core-fabric"-style value once this leaf's
+		// own build.gradle.kts runs (module scripts execute after this subprojects{} block, and
+		// allprojects{} - which seeds the "archie-core" prefix - runs after it too) - reading it here
+		// would still see the base plugin's raw default ("1.21.1", from project.name). Defer until
+		// this project has finished configuring.
+		afterEvaluate {
+			extensions.configure<PublishingExtension>("publishing") {
+				publications {
+					create<MavenPublication>("maven") {
+						artifactId = base.archivesName.get()
+						from(components["java"])
+					}
 				}
-			}
-
-			repositories {
-				mavenLocal()
-				maven {
-					name = "Reposilite"
-					val releasesUrl = "https://maven.kernelpanicsoft.net/releases"
-					val snapshotsUrl = "https://maven.kernelpanicsoft.net/snapshots"
-
-					url = uri(if (version.toString().endsWith("SNAPSHOT")) snapshotsUrl else releasesUrl)
 
-					credentials {
-						username = localProperties?.getProperty("reposilite.username")
-							?: System.getenv("REPOSILITE_USERNAME")
-						password = localProperties?.getProperty("reposilite.password")
-							?: System.getenv("REPOSILITE_PASSWORD")
+				repositories {
+					mavenLocal()
+					maven {
+						name = "Reposilite"
+						val releasesUrl = "https://maven.kernelpanicsoft.net/releases"
+						val snapshotsUrl = "https://maven.kernelpanicsoft.net/snapshots"
+
+						url = uri(if (version.toString().endsWith("SNAPSHOT")) snapshotsUrl else releasesUrl)
+
+						credentials {
+							username = localProperties?.getProperty("reposilite.username")
+								?: System.getenv("REPOSILITE_USERNAME")
+							password = localProperties?.getProperty("reposilite.password")
+								?: System.getenv("REPOSILITE_PASSWORD")
+						}
 					}
 				}
 			}
@@ -158,6 +179,11 @@ subprojects {
 }
 
 allprojects {
+	// Stonecutter's tree/branch anchors (e.g. `:core`) are synthetic container projects with real
+	// leaf projects nested under them - they must not get build plugins applied to them directly.
+	// The true root project still needs this block (e.g. for its own `publish` task).
+	if (this != rootProject && subprojects.isNotEmpty()) return@allprojects
+
 	apply(plugin = "java")
 	apply(plugin = "org.jetbrains.kotlin.jvm")
 	apply(plugin = "org.jetbrains.kotlin.plugin.serialization")
@@ -200,14 +226,38 @@ fusioner {
 	jarVersion = project.version.toString()
 	outputDirectory = "build/artifacts"
 
+	// modfusioner finds each side's source project by bare Project.name (case-insensitive), searched
+	// across the *entire* build - but under Stonecutter every tree (core/datagen/gametest/test) has a
+	// leaf literally named "fabric" and one named "neoforge", so no name resolves uniquely to core's.
+	// ":core" is an existing, globally-unique container project name - point both sides at it just to
+	// satisfy modfusioner's "did we find >= 2 projects" check; `inputFile` (set below, once every
+	// project has finished configuring) overrides where the actual jar is read from, resolved relative
+	// to that anchor project's directory.
 	fabric {
-		projectName = "archie-core-fabric"
-		inputTaskName = "remapJar"
+		projectName = "core"
 	}
 
 	neoforge {
-		projectName = "archie-core-neoforge"
-		inputTaskName = "remapJar"
+		projectName = "core"
+	}
+}
+
+// modfusioner reads `inputFile` as `File(<projectName's projectDir>, inputFile)` - `projectName` above
+// is just an anchor, so compute the real remapJar output path here (deferred to gradle.projectsEvaluated
+// so base.archivesName - and therefore the jar's real filename - has reached its final value) and
+// express it relative to :core's directory.
+gradle.projectsEvaluated {
+	val mcVersion = libs.versions.minecraft.get()
+	val coreDir = project(":core").projectDir
+
+	fun remapJarFile(path: String) =
+		(project(path).tasks.named("remapJar").get() as AbstractArchiveTask).archiveFile.get().asFile
+
+	project.extensions.getByType<FusionerExtension>().let { fusionerExtension ->
+		fusionerExtension.fabricConfiguration.inputFile =
+			remapJarFile(":core:fabric:$mcVersion").relativeTo(coreDir).path
+		fusionerExtension.neoforgeConfiguration.inputFile =
+			remapJarFile(":core:neoforge:$mcVersion").relativeTo(coreDir).path
 	}
 }
 
@@ -224,7 +274,7 @@ publisher {
 
 	projectVersion = "${libs.versions.minecraft.get()}-${project.version}"
 	displayName = "Archie-Merged-${projectVersion.get()}"
-	gameVersions = listOf("1.21.1")
+	gameVersions = listOf(libs.versions.minecraft.get())
 	loaders = listOf("neoforge", "fabric")
 	curseEnvironment = "both"
 	versionType = "alpha"
@@ -243,15 +293,12 @@ publisher {
 }
 
 dependencies {
-	dokka(project(":archie-core-common")) { isTransitive = false }
-	dokka(project(":archie-core-fabric")) { isTransitive = false }
-	dokka(project(":archie-core-neoforge")) { isTransitive = false }
-	dokka(project(":archie-datagen-common")) { isTransitive = false }
-	dokka(project(":archie-datagen-fabric")) { isTransitive = false }
-	dokka(project(":archie-datagen-neoforge")) { isTransitive = false }
-	dokka(project(":archie-gametest-common")) { isTransitive = false }
-	dokka(project(":archie-gametest-fabric")) { isTransitive = false }
-	dokka(project(":archie-gametest-neoforge")) { isTransitive = false }
+	val mcVersion = libs.versions.minecraft.get()
+	listOf("core", "datagen", "gametest").forEach { tree ->
+		listOf("common", "fabric", "neoforge").forEach { branch ->
+			dokka(project(":$tree:$branch:$mcVersion")) { isTransitive = false }
+		}
+	}
 }
 
 tasks {
@@ -269,20 +316,8 @@ tasks {
 		group = "publishing"
 		val tag = rootProject.version.toString().substringBeforeLast(".")
 		workingDir = rootDir
-		// --alias-type redirect: mike's default ("symlink") writes the "latest" alias as an
-		// actual symlink into the gh-pages branch, which GitHub's own automatic Pages
-		// build-and-deploy (triggered whenever gh-pages is pushed, separate from this task)
-		// rejects outright ("content does not contain any hard links, symlinks"). "redirect"
-		// makes the alias a small HTML redirect page instead - no symlink, same effect for
-		// visitors.
 		commandLine("mike", "deploy", "--push", "--update-aliases", "--alias-type", "redirect", tag, "latest")
 	}
-	// modpublisher's changelog reads CHANGELOG.md straight off disk when a publish task runs - it
-	// doesn't know about git tags or PRs. .github/workflows/release-notes.yaml (reactive, post-tag)
-	// can't help here: by the time it would generate this release's entry, the publish task attached
-	// to the tag has already read (and shipped) whatever was on disk before. This task closes that
-	// gap by generating CHANGELOG.md synchronously - see .github/scripts/generate_release_notes.py's
-	// module docstring for the two call shapes.
 	register<Exec>("generateChangelog") {
 		group = "publishing"
 		workingDir = rootDir
diff --git a/core/common/build.gradle.kts b/core/common/build.gradle.kts
index 6bb4f71fb..17df7c227 100644
--- a/core/common/build.gradle.kts
+++ b/core/common/build.gradle.kts
@@ -21,10 +21,13 @@ val sharedProperties = kotlin.runCatching {
 val String.prop: String?
 	get() = sharedProperties?.get(this)?.toString()
 
+val branchDir = projectDir.parentFile.parentFile
+
 loom {
-	accessWidenerPath = file("src/main/resources/${"mod_id".prop}.accesswidener")
+	accessWidenerPath = branchDir.resolve("src/main/resources/${"mod_id".prop}.accesswidener")
 }
 
+
 dependencies {
 	compileOnly(kotlin("reflect"))
 	implementation(libs.junit.jupiter.api)
@@ -39,19 +42,10 @@ dependencies {
 	api(libs.kotlinx.serialization.json5) { isTransitive = false }
 	api(libs.kotlinx.serialization.cbor) { isTransitive = false }
 	api(compose.runtime)
-	// Used only for the fabric @Environment annotations + mixin deps. Do NOT use other classes
-	// from fabric loader from common code.
 	modImplementation(libs.fabric.loader)
 
 	modApi(libs.rei.common)
 	modCompileOnly(libs.clothConfig.common)
-	// Cloth Config's own transitive dependency, kept visible at compile time only (like Cloth
-	// Config itself) since the config system exposes `Color` directly in its own public API -
-	// NOT bundled: Cloth Config's own distributed jar already jar-in-jars this and exports
-	// `me.shedaniel.math` itself, so embedding a second copy makes NeoForge's ModLauncher refuse
-	// to even build its module layer ("Modules basic.math and cloth_config export package
-	// me.shedaniel.math") the moment both are present - confirmed by actually hitting that crash.
-	// [ColorSerializer]/[SColor] stay gated behind isClothConfigLoaded instead, same as ModifierKeyCode.
 	compileOnlyApi(libs.cloth.basic.math)
 	modApi(libs.architectury.common)
 	modApi(libs.storage.common)
@@ -61,20 +55,20 @@ dependencies {
 tasks {
 	base.archivesName.set(base.archivesName.get() + "-common")
 
-	val verifyGuiSpriteAssets by registering {
+	val verifyGuiSpriteAssets = register("verifyGuiSpriteAssets") {
 		group = "verification"
 		description = "Verifies GUI sprite metadata files have matching PNG assets."
 
 		doLast {
-			val spritesDir = file("src/main/resources/assets/archie/textures/gui/sprites")
+			val spritesDir = branchDir.resolve("src/main/resources/assets/archie/textures/gui/sprites")
 			if (!spritesDir.exists()) return@doLast
 
 			val missingPng = spritesDir
 				.walkTopDown()
 				.filter { it.isFile && it.name.endsWith(".png.mcmeta") }
-				.map { it to file(it.path.removeSuffix(".mcmeta")) }
+				.map { it to File(it.path.removeSuffix(".mcmeta")) }
 				.filter { (_, png) -> !png.exists() }
-				.map { (meta, _) -> meta.relativeTo(projectDir).invariantSeparatorsPath }
+				.map { (meta, _) -> meta.relativeTo(branchDir).invariantSeparatorsPath }
 				.toList()
 
 			if (missingPng.isNotEmpty()) {
diff --git a/core/fabric/build.gradle.kts b/core/fabric/build.gradle.kts
index c54d928de..5d3caca17 100644
--- a/core/fabric/build.gradle.kts
+++ b/core/fabric/build.gradle.kts
@@ -1,3 +1,4 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
 import net.kernelpanicsoft.archie.plugin.bundleMod
 import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
 import net.kernelpanicsoft.archie.plugin.runtimeLibrary
@@ -12,8 +13,13 @@ architectury {
 	fabric()
 }
 
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
 actualizer {
-	actualizes(project(":archie-core-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -26,7 +32,7 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(common.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -75,8 +81,8 @@ dependencies {
 	testRuntimeOnly(libs.junit.jupiter.engine)
 	runtimeLibrary(libs.kotlinx.coroutines.test)
 
-	"common"(project(":archie-core-common", "namedElements")) { isTransitive = false }
-	"shadowCommon"(project(":archie-core-common", "transformProductionFabric")) { isTransitive = false }
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	"shadowCommon"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
 }
 
 modResources {
@@ -91,7 +97,7 @@ tasks {
 	}
 
 	processResources {
-		from(project(":archie-core-common").sourceSets.main.get().resources) {
+		from(common.sourceSets.main.get().resources) {
 			include("assets/archie/**")
 			include("data/archie/**")
 			include("archie-common.mixins.json")
@@ -124,11 +130,11 @@ tasks {
 
 	jar {
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-		from(project(":archie-core-common").sourceSets.main.get().output)
+		from(common.sourceSets.main.get().output)
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-core-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/core/neoforge/build.gradle.kts b/core/neoforge/build.gradle.kts
index a94b0843f..37307559d 100644
--- a/core/neoforge/build.gradle.kts
+++ b/core/neoforge/build.gradle.kts
@@ -1,3 +1,4 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
 import net.kernelpanicsoft.archie.plugin.bundleMod
 import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
 import net.kernelpanicsoft.archie.plugin.runtimeLibrary
@@ -12,8 +13,13 @@ architectury {
 	neoForge()
 }
 
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
 actualizer {
-	actualizes(project(":archie-core-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -31,16 +37,12 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(common.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
 			sourceSet(sourceSets.main.get())
-			// actualizer only merges Kotlin expect/actual source into this project's own
-			// compilation - plain Java files in archie-core-common (e.g. mixin classes with no
-			// actual/expect involvement) never get copied in, so they're invisible to FML's
-			// dev-mode module layer unless their sourceSet is also registered here directly.
-			sourceSet(project(":archie-core-common").sourceSets.main.get())
+			sourceSet(common.sourceSets.main.get())
 		}
 	}
 
@@ -72,9 +74,6 @@ dependencies {
 	bundleRuntimeLibrary(libs.kotlinx.serialization.json5)
 	bundleRuntimeLibrary(libs.kotlinx.serialization.cbor)
 	bundleRuntimeLibrary(compose.runtime)
-	// compose.runtime's own transitive deps; Loom's dev-run GAMELIBRARY discovery doesn't walk
-	// transitive deps of a bundled library the way production JarJar packaging does, so each needs
-	// its own explicit declaration to be visible during runClient/runClientNeoForge.
 	bundleRuntimeLibrary(libs.androidx.annotation)
 	bundleRuntimeLibrary(libs.androidx.collection)
 	bundleRuntimeLibrary(libs.okio)
@@ -92,8 +91,8 @@ dependencies {
 	testRuntimeOnly(libs.junit.jupiter.engine)
 	runtimeLibrary(libs.kotlinx.coroutines.test)
 
-	"common"(project(":archie-core-common", "namedElements")) { isTransitive = false }
-	"shadowCommon"(project(":archie-core-common", "transformProductionNeoForge")) { isTransitive = false }
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	"shadowCommon"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
 }
 
 modResources {
@@ -108,7 +107,7 @@ tasks {
 	}
 
 	processResources {
-		from(project(":archie-core-common").sourceSets.main.get().resources) {
+		from(common.sourceSets.main.get().resources) {
 			include("assets/archie/**")
 			include("data/archie/**")
 			include("archie-common.mixins.json")
@@ -142,11 +141,11 @@ tasks {
 
 	jar {
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-		from(project(":archie-core-common").sourceSets.main.get().output)
+		from(common.sourceSets.main.get().output)
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-core-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/core/stonecutter.gradle.kts b/core/stonecutter.gradle.kts
new file mode 100644
index 000000000..501dc597c
--- /dev/null
+++ b/core/stonecutter.gradle.kts
@@ -0,0 +1,5 @@
+plugins {
+	id("dev.kikugie.stonecutter")
+}
+
+stonecutter active "1.21.1"
diff --git a/datagen/common/build.gradle.kts b/datagen/common/build.gradle.kts
index fd20fb2e3..3c26db2fc 100644
--- a/datagen/common/build.gradle.kts
+++ b/datagen/common/build.gradle.kts
@@ -6,13 +6,28 @@ actualizer {
 	stubUnfulfilledExpects()
 }
 
+// Cross-tree reference: datagen and core are separate Stonecutter trees, so node.sibling() (which
+// only searches within the current tree) doesn't reach core - resolve the path directly instead.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 }
 
 dependencies {
-	api(project(":archie-core-common", "namedElements"))
+	api(files(coreCommon.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(libs.kotlinx.serialization)
+	api(libs.kotlinx.serialization.json)
+	api(libs.kotlinx.serialization.nbt) { isTransitive = false }
+	api(libs.kotlinx.serialization.toml) { isTransitive = false }
+	api(libs.kotlinx.serialization.json5) { isTransitive = false }
+	api(libs.kotlinx.serialization.cbor) { isTransitive = false }
+	api(compose.runtime)
+	modCompileOnly(libs.clothConfig.common)
+	compileOnlyApi(libs.cloth.basic.math)
 	modApi(libs.architectury.common)
+	modApi(libs.storage.common)
+	modApi(libs.storage.resources.common)
 
 	compileOnly(kotlin("reflect"))
 	implementation(libs.junit.jupiter.api)
diff --git a/datagen/fabric/build.gradle.kts b/datagen/fabric/build.gradle.kts
index 9045cddfe..a161112f9 100644
--- a/datagen/fabric/build.gradle.kts
+++ b/datagen/fabric/build.gradle.kts
@@ -1,4 +1,6 @@
-import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
+import org.gradle.api.tasks.bundling.Jar
 
 plugins {
 	alias(libs.plugins.archie)
@@ -9,8 +11,19 @@ architectury {
 	fabric()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: datagen and core are separate Stonecutter trees, so node.sibling()
+// (which only searches within the current tree) doesn't reach core - resolve the path directly.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val coreFabric = rootProject.project(":core:fabric:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-datagen-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -22,7 +35,7 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -73,8 +86,13 @@ dependencies {
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-datagen-common", "namedElements")) { isTransitive = false }
-	api(project(":archie-core-fabric", "namedElements"))
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreFabric.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	modApi(libs.architectury.fabric)
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -100,7 +118,7 @@ tasks {
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-datagen-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/datagen/neoforge/build.gradle.kts b/datagen/neoforge/build.gradle.kts
index 58194507f..3101b7510 100644
--- a/datagen/neoforge/build.gradle.kts
+++ b/datagen/neoforge/build.gradle.kts
@@ -1,5 +1,8 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
 import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
 import org.gradle.api.tasks.bundling.AbstractArchiveTask
+import org.gradle.api.tasks.bundling.Jar
 
 plugins {
 	alias(libs.plugins.archie)
@@ -10,8 +13,19 @@ architectury {
 	neoForge()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: datagen and core are separate Stonecutter trees, so node.sibling()
+// (which only searches within the current tree) doesn't reach core - resolve the path directly.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val coreNeoforge = rootProject.project(":core:neoforge:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-datagen-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -27,7 +41,7 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -72,8 +86,12 @@ dependencies {
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-datagen-common", "namedElements")) { isTransitive = false }
-	api(project(":archie-core-neoforge", "namedElements"))
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreNeoforge.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -99,7 +117,7 @@ tasks {
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-datagen-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/datagen/stonecutter.gradle.kts b/datagen/stonecutter.gradle.kts
new file mode 100644
index 000000000..501dc597c
--- /dev/null
+++ b/datagen/stonecutter.gradle.kts
@@ -0,0 +1,5 @@
+plugins {
+	id("dev.kikugie.stonecutter")
+}
+
+stonecutter active "1.21.1"
diff --git a/gametest/common/build.gradle.kts b/gametest/common/build.gradle.kts
index 9817344b3..2da4e76bc 100644
--- a/gametest/common/build.gradle.kts
+++ b/gametest/common/build.gradle.kts
@@ -8,12 +8,25 @@ actualizer {
 	stubUnfulfilledExpects()
 }
 
+// Cross-tree reference: gametest and core are separate Stonecutter trees, so node.sibling() (which
+// only searches within the current tree) doesn't reach core - resolve the path directly instead.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 }
 
 dependencies {
-	api(project(":archie-core-common", "namedElements"))
+	// See core/fabric/build.gradle.kts and datagen/common/build.gradle.kts for why this depends on
+	// core-common's "jar" task output directly, and why the Compose dependency is repeated below.
+	api(files(coreCommon.tasks.named<org.gradle.api.tasks.bundling.Jar>("jar").flatMap { it.archiveFile }))
+	api(compose.runtime)
+	api(libs.kotlinx.serialization)
+	api(libs.kotlinx.serialization.json)
+	api(libs.kotlinx.serialization.nbt) { isTransitive = false }
+	api(libs.kotlinx.serialization.toml) { isTransitive = false }
+	api(libs.kotlinx.serialization.json5) { isTransitive = false }
+	api(libs.kotlinx.serialization.cbor) { isTransitive = false }
 	modApi(libs.architectury.common)
 	modApi(libs.storage.common)
 	modApi(libs.storage.resources.common)
diff --git a/gametest/fabric/build.gradle.kts b/gametest/fabric/build.gradle.kts
index b64d41606..5573badc6 100644
--- a/gametest/fabric/build.gradle.kts
+++ b/gametest/fabric/build.gradle.kts
@@ -1,3 +1,8 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
+import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
+import org.gradle.api.tasks.bundling.Jar
+
 plugins {
 	alias(libs.plugins.archie)
 }
@@ -7,8 +12,19 @@ architectury {
 	fabric()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: gametest and core are separate Stonecutter trees, so node.sibling()
+// (which only searches within the current tree) doesn't reach core - resolve the path directly.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val coreFabric = rootProject.project(":core:fabric:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-gametest-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -20,7 +36,7 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -66,11 +82,19 @@ dependencies {
 	modLocalRuntime(libs.clothConfig.fabric)
 
 	implementation(libs.junit.jupiter.api)
+	implementation(libs.kotlinx.coroutines.test)
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-gametest-common", "namedElements")) { isTransitive = false }
-	api(project(":archie-core-fabric", "namedElements"))
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreFabric.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	modApi(libs.architectury.fabric)
+	modImplementation(libs.storage.common)
+	modImplementation(libs.storage.resources.common)
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -96,7 +120,7 @@ tasks {
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-gametest-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/gametest/neoforge/build.gradle.kts b/gametest/neoforge/build.gradle.kts
index 0831174c5..301a1be2a 100644
--- a/gametest/neoforge/build.gradle.kts
+++ b/gametest/neoforge/build.gradle.kts
@@ -1,4 +1,8 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
+import net.kernelpanicsoft.archie.plugin.bundleRuntimeLibrary
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
 import org.gradle.api.tasks.bundling.AbstractArchiveTask
+import org.gradle.api.tasks.bundling.Jar
 
 plugins {
 	alias(libs.plugins.archie)
@@ -9,8 +13,19 @@ architectury {
 	neoForge()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: gametest and core are separate Stonecutter trees, so node.sibling()
+// (which only searches within the current tree) doesn't reach core - resolve the path directly.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val coreNeoforge = rootProject.project(":core:neoforge:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-gametest-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -26,7 +41,7 @@ configurations {
 }
 
 loom {
-	accessWidenerPath.set(project(":archie-core-common").loom.accessWidenerPath)
+	accessWidenerPath.set(coreCommon.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -76,11 +91,17 @@ dependencies {
 	modApi(libs.architectury.neoforge)
 
 	implementation(libs.junit.jupiter.api)
+	implementation(libs.kotlinx.coroutines.test)
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-gametest-common", "namedElements")) { isTransitive = false }
-	api(project(":archie-core-neoforge", "namedElements"))
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreNeoforge.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	modImplementation(libs.storage.neoforge) { exclude(group = "curse.maven") }
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -106,7 +127,7 @@ tasks {
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-gametest-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/gametest/stonecutter.gradle.kts b/gametest/stonecutter.gradle.kts
new file mode 100644
index 000000000..501dc597c
--- /dev/null
+++ b/gametest/stonecutter.gradle.kts
@@ -0,0 +1,5 @@
+plugins {
+	id("dev.kikugie.stonecutter")
+}
+
+stonecutter active "1.21.1"
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index c9f00784d..e0cc8ca2c 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -18,7 +18,7 @@ parchment = "2024.11.17"
 
 architectury = "13.0.8"
 architectury-plugin = { require = "[3.4, 3.5[" }
-architectury-loom = { require = "1.13.469" }
+architectury-loom = { require = "1.17.491" }
 architectury-kotlin = "2.0.0"
 
 modfusioner = "1.0.12"
@@ -51,7 +51,7 @@ quilt-parsers = "0.2.1"
 knbt = "0.11.4"
 tomlkt = "0.3.7"
 json5k = "0.3.0"
-shadow = "8.1.1"
+shadow = "9.6.1"
 compose = "1.7.1"
 dokka-mkdocs = "0.6.1"
 junit = "5.11.4"
@@ -124,6 +124,7 @@ neoforge = { module = "net.neoforged:neoforge", version.ref = "neoforge" }
 modmenu = { module = "com.terraformersmc:modmenu", version.ref = "modmenu" }
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit" }
+junit-platform-launcher = { module = "org.junit.platform:junit-platform-launcher", version.ref = "junit-platform" }
 
 [plugins]
 kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
@@ -137,7 +138,7 @@ architectury = { id = "architectury-plugin", version.ref = "architectury-plugin"
 architectury-loom = { id = "dev.architectury.loom", version.ref = "architectury-loom" }
 architectury-kotlin = { id = "net.kernelpanicsoft.architectury.kotlin", version.ref = "architectury-kotlin" }
 
-shadow = { id = "com.github.johnrengelman.shadow", version.ref = "shadow" }
+shadow = { id = "com.gradleup.shadow", version.ref = "shadow" }
 modfusioner = { id = "com.hypherionmc.modutils.modfusioner", version.ref = "modfusioner" }
 modpublisher = { id = "com.hypherionmc.modutils.modpublisher", version.ref = "modpublisher" }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index cea7a793a..c42672d95 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 4cd9a8e67..f168a6fe2 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,7 +1,3 @@
-enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS")
-
-rootProject.name = "Archie"
-
 pluginManagement {
 	repositories {
 		maven("https://maven.fabricmc.net/")
@@ -22,21 +18,16 @@ pluginManagement {
 	}
 }
 
-includeModule("core")
-
-includeModule("datagen")
-
-includeModule("gametest")
-
-includeModule("test")
-
-fun includeModulePlatform(name: String, platform: String) {
-	include("$name/$platform")
-	project(":$name/$platform").name = "archie-$name-$platform"
+plugins {
+	id("dev.kikugie.stonecutter") version "0.9.7"
 }
 
-fun includeModule(name: String) {
-	includeModulePlatform(name, "common")
-	includeModulePlatform(name, "fabric")
-	includeModulePlatform(name, "neoforge")
+stonecutter {
+	for (tree in listOf("core", "datagen", "gametest", "test")) create(tree) {
+		branch("common") { versions("1.21.1") }
+		branch("fabric") { versions("1.21.1") }
+		branch("neoforge") { versions("1.21.1") }
+	}
 }
+
+rootProject.name = "Archie"
diff --git a/test/common/build.gradle.kts b/test/common/build.gradle.kts
index 2efc4d2e5..2a23270c8 100644
--- a/test/common/build.gradle.kts
+++ b/test/common/build.gradle.kts
@@ -6,16 +6,39 @@ actualizer {
 	stubUnfulfilledExpects()
 }
 
+// Cross-tree references: test, core, datagen and gametest are separate Stonecutter trees, so
+// node.sibling() (which only searches within the current tree) doesn't reach them - resolve the
+// paths directly instead.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val datagenCommon = rootProject.project(":datagen:common:${stonecutter.current.version}")
+val gametestCommon = rootProject.project(":gametest:common:${stonecutter.current.version}")
+
+// Stonecutter's real projectDir for a node is its `versions/<version>/` folder, two levels below
+// this branch's own directory (where the shared `src/` this build script's paths mean actually
+// lives) - branchDir undoes that so plain file(...)-style paths below resolve correctly.
+val branchDir = projectDir.parentFile.parentFile
+
 loom {
 	log4jConfigs.from(rootDir.resolve("log4j-dev.xml"))
-	accessWidenerPath = file("src/main/resources/archie_test.accesswidener")
+	accessWidenerPath = branchDir.resolve("src/main/resources/archie_test.accesswidener")
 	enableTransitiveAccessWideners = true
 }
 
 dependencies {
-	api(project(":archie-core-common", "namedElements"))
-	api(project(":archie-datagen-common", "namedElements"))
-	api(project(":archie-gametest-common", "namedElements"))
+	// See core/fabric/build.gradle.kts and datagen/common/build.gradle.kts for why these depend on
+	// each sibling's "jar" task output directly rather than through a project(path) reference, and
+	// why the Compose/serialization deps are repeated below - files() dependencies carry no
+	// transitive module metadata, and core-common's own `api` surface is needed here too.
+	api(files(coreCommon.tasks.named<org.gradle.api.tasks.bundling.Jar>("jar").flatMap { it.archiveFile }))
+	api(files(datagenCommon.tasks.named<org.gradle.api.tasks.bundling.Jar>("jar").flatMap { it.archiveFile }))
+	api(files(gametestCommon.tasks.named<org.gradle.api.tasks.bundling.Jar>("jar").flatMap { it.archiveFile }))
+	api(compose.runtime)
+	api(libs.kotlinx.serialization)
+	api(libs.kotlinx.serialization.json)
+	api(libs.kotlinx.serialization.nbt) { isTransitive = false }
+	api(libs.kotlinx.serialization.toml) { isTransitive = false }
+	api(libs.kotlinx.serialization.json5) { isTransitive = false }
+	api(libs.kotlinx.serialization.cbor) { isTransitive = false }
 
 	testImplementation(libs.junit.jupiter.api)
 	testImplementation(kotlin("reflect"))
diff --git a/test/fabric/build.gradle.kts b/test/fabric/build.gradle.kts
index fa0fe9dff..0b314b8ef 100644
--- a/test/fabric/build.gradle.kts
+++ b/test/fabric/build.gradle.kts
@@ -1,4 +1,7 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
 import net.kernelpanicsoft.archie.plugin.bundleMod
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
+import org.gradle.api.tasks.bundling.Jar
 
 plugins {
 	alias(libs.plugins.shadow)
@@ -10,8 +13,22 @@ architectury {
 	fabric()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: test, core, datagen and gametest are separate Stonecutter trees, so
+// node.sibling() (which only searches within the current tree) doesn't reach them - resolve the
+// paths directly instead.
+val coreCommon = rootProject.project(":core:common:${stonecutter.current.version}")
+val coreFabric = rootProject.project(":core:fabric:${stonecutter.current.version}")
+val datagenFabric = rootProject.project(":datagen:fabric:${stonecutter.current.version}")
+val gametestFabric = rootProject.project(":gametest:fabric:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-test-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -24,8 +41,8 @@ configurations {
 }
 
 loom {
-	log4jConfigs.from(project(":archie-test-common").loom.log4jConfigs)
-	accessWidenerPath.set(project(":archie-test-common").loom.accessWidenerPath)
+	log4jConfigs.from(common.loom.log4jConfigs)
+	accessWidenerPath.set(common.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -93,16 +110,32 @@ dependencies {
 	bundleMod(libs.storage.fabric)
 
 	implementation(libs.junit.jupiter.api)
+	implementation(libs.kotlinx.coroutines.test)
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-test-common", "namedElements")) { isTransitive = false }
-	"shadowCommon"(project(":archie-test-common", "transformProductionFabric")) { isTransitive = false }
-	api(project(":archie-core-fabric", "namedElements"))
-	api(project(":archie-datagen-fabric", "namedElements"))
-	api(project(":archie-gametest-fabric", "namedElements"))
-	// See the matching comment in gametest/fabric/build.gradle.kts.
-	runtimeOnly(project(":archie-core-common", "namedElements")) { isTransitive = false }
+	// See core/fabric/build.gradle.kts and gametest/fabric/build.gradle.kts for why these depend on
+	// the sibling's "jar" task output directly, and why the Compose/storage/coroutines deps above
+	// and below are repeated - the actualizer merges test-common's own source files into this
+	// project's own compilation, so it needs test-common's compile-time deps directly too, not just
+	// its output.
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	"shadowCommon"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreFabric.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(datagenFabric.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(gametestFabric.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	runtimeOnly(files(coreCommon.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	modImplementation(libs.storage.common)
+	modImplementation(libs.storage.resources.common)
+	// files() dependencies carry no runtime GAMELIBRARY discovery either - the serialization format
+	// add-ons core-fabric bundles at runtime (nbt/toml/json5, needed by Archie's own Config system
+	// at init) don't propagate, so they're repeated here too. Confirmed missing live: a
+	// NoClassDefFoundError for io.github.xn32.json5k.ConfigBuilder when actually launching this
+	// project.
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -117,7 +150,7 @@ tasks {
 	}
 
 	processResources {
-		from(project(":archie-test-common").sourceSets.main.get().resources) {
+		from(common.sourceSets.main.get().resources) {
 			include("assets/archie_test/**")
 			include("data/archie_test/**")
 			include("archie_test.common.json")
@@ -148,7 +181,7 @@ tasks {
 	jar.get().archiveClassifier.set("dev")
 
 	sourcesJar {
-		val commonSources = project(":archie-test-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/test/neoforge/build.gradle.kts b/test/neoforge/build.gradle.kts
index e8f6213de..944915af2 100644
--- a/test/neoforge/build.gradle.kts
+++ b/test/neoforge/build.gradle.kts
@@ -1,4 +1,7 @@
+import dev.kikugie.stonecutter.build.StonecutterBuildExtension
 import net.kernelpanicsoft.archie.plugin.bundleMod
+import net.kernelpanicsoft.archie.plugin.runtimeLibrary
+import org.gradle.api.tasks.bundling.Jar
 
 plugins {
 	alias(libs.plugins.shadow)
@@ -10,8 +13,21 @@ architectury {
 	neoForge()
 }
 
+// Same-tree sibling. See core/fabric/build.gradle.kts for why node.sibling() is used here.
+val commonNode = requireNotNull(extensions.getByType<StonecutterBuildExtension>().node.sibling("common")) {
+	"No common project for $project"
+}
+val common: Project = commonNode.project
+
+// Cross-tree references: test, core, datagen and gametest are separate Stonecutter trees, so
+// node.sibling() (which only searches within the current tree) doesn't reach them - resolve the
+// paths directly instead.
+val coreNeoforge = rootProject.project(":core:neoforge:${stonecutter.current.version}")
+val datagenNeoforge = rootProject.project(":datagen:neoforge:${stonecutter.current.version}")
+val gametestNeoforge = rootProject.project(":gametest:neoforge:${stonecutter.current.version}")
+
 actualizer {
-	actualizes(project(":archie-test-common"))
+	actualizes(common)
 }
 
 configurations {
@@ -29,8 +45,8 @@ configurations {
 }
 
 loom {
-	log4jConfigs.from(project(":archie-test-common").loom.log4jConfigs)
-	accessWidenerPath.set(project(":archie-test-common").loom.accessWidenerPath)
+	log4jConfigs.from(common.loom.log4jConfigs)
+	accessWidenerPath.set(common.loom.accessWidenerPath)
 
 	mods {
 		maybeCreate("main").apply {
@@ -104,14 +120,28 @@ dependencies {
 	bundleMod(libs.storage.neoforge) { exclude(group = "curse.maven") }
 
 	implementation(libs.junit.jupiter.api)
+	implementation(libs.kotlinx.coroutines.test)
 	testImplementation(libs.junit.jupiter.api)
 	testRuntimeOnly(libs.junit.jupiter.engine)
 
-	"common"(project(":archie-test-common", "namedElements")) { isTransitive = false }
-	"shadowCommon"(project(":archie-test-common", "transformProductionNeoForge")) { isTransitive = false }
-	api(project(":archie-core-neoforge", "namedElements"))
-	api(project(":archie-datagen-neoforge", "namedElements"))
-	api(project(":archie-gametest-neoforge", "namedElements"))
+	// See core/fabric/build.gradle.kts and gametest/neoforge/build.gradle.kts for why these depend
+	// on the sibling's "jar" task output directly, and why the Compose/coroutines deps above and
+	// below are repeated - the actualizer merges test-common's own source files into this project's
+	// own compilation, so it needs test-common's compile-time deps directly too, not just its output.
+	"common"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	"shadowCommon"(files(common.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(coreNeoforge.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(datagenNeoforge.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	api(files(gametestNeoforge.tasks.named<Jar>("jar").flatMap { it.archiveFile }))
+	// files() dependencies carry no runtime GAMELIBRARY discovery either - the serialization format
+	// add-ons core-neoforge bundles at runtime (nbt/toml/json5, needed by Archie's own Config system
+	// at init) don't propagate, so they're repeated here too. Confirmed missing live: a
+	// NoClassDefFoundError for io.github.xn32.json5k.ConfigBuilder when actually launching this
+	// project.
+	runtimeLibrary(libs.kotlinx.serialization.nbt)
+	runtimeLibrary(libs.kotlinx.serialization.toml)
+	runtimeLibrary(libs.kotlinx.serialization.json5)
+	runtimeLibrary(compose.runtime)
 }
 
 modResources {
@@ -126,7 +156,7 @@ tasks {
 	}
 
 	processResources {
-		from(project(":archie-test-common").sourceSets.main.get().resources) {
+		from(common.sourceSets.main.get().resources) {
 			include("assets/archie_test/**")
 			include("data/archie_test/**")
 			include("archie_test.common.json")
@@ -159,11 +189,11 @@ tasks {
 
 	jar {
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-		from(project(":archie-test-common").sourceSets.main.get().output)
+		from(common.sourceSets.main.get().output)
 	}
 
 	sourcesJar {
-		val commonSources = project(":archie-test-common").tasks.sourcesJar
+		val commonSources = common.tasks.sourcesJar
 		dependsOn(commonSources)
 		duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 		from(commonSources.get().archiveFile.map { zipTree(it) })
diff --git a/test/stonecutter.gradle.kts b/test/stonecutter.gradle.kts
new file mode 100644
index 000000000..501dc597c
--- /dev/null
+++ b/test/stonecutter.gradle.kts
@@ -0,0 +1,5 @@
+plugins {
+	id("dev.kikugie.stonecutter")
+}
+
+stonecutter active "1.21.1"