diff --git a/build.gradle.kts b/build.gradle.kts
index db77430..715ab0a 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -32,14 +32,18 @@ repositories {
     mavenCentral()
 }
 
-dependencies {
-    implementation(platform("org.apache.logging.log4j:log4j-bom:2.25.2"))
-    implementation("org.apache.logging.log4j:log4j-api")
-    runtimeOnly("org.apache.logging.log4j:log4j-core")
-    compileOnly("org.jetbrains:annotations:26.0.2-1")
+val detag by configurations.creating {
+    isCanBeConsumed = false
+    isCanBeResolved = true
+}
 
-    implementation("com.r35157.libs:valuetypes-basic-api:0.1-dev")
-    implementation("com.r35157.nenjim:valuetypes-api:0.1-dev")
+dependencies {
+    detag("com.r35157.tools:detag-impl_ref:0.1-dev")
+    compileOnly("org.jetbrains:annotations:26.1.0")
+    runtimeOnly("org.apache.logging.log4j:log4j-core:2.26.0")
+    runtimeOnly("org.apache.logging.log4j:log4j-slf4j2-impl:2.26.0")
+
+    implementation("org.slf4j:slf4j-api:2.0.18")
     implementation("com.r35157.nenjim:hubd-api:0.1-dev")
 }
 
@@ -49,6 +53,54 @@ java {
 
 tasks.withType<JavaCompile>().configureEach {
     options.release.set(25)
+    options.compilerArgs.addAll(listOf("-Xmaxerrs", "1"))
+}
+
+val generatedDetagMain = layout.buildDirectory.dir("generated/sources/detag/main/java")
+
+val cleanGeneratedDetagMain by tasks.registering(Delete::class) {
+    delete(generatedDetagMain)
+}
+
+val detagMain by tasks.registering(JavaExec::class) {
+    group = "build"
+    description = "Generates Java sources from .tjava files"
+
+    classpath = detag
+    mainClass.set("com.r35157.tools.detag.impl.ref.Main")
+
+    val configFile = layout.projectDirectory.file("../detag.conf")
+    val sourceRoot = layout.projectDirectory.dir("src/main/tjava")
+
+    inputs.file(configFile)
+    inputs.dir(sourceRoot)
+    outputs.dir(generatedDetagMain)
+
+    dependsOn(cleanGeneratedDetagMain)
+
+    args(
+        "--config", configFile.asFile.absolutePath,
+        "--source-root", sourceRoot.asFile.absolutePath,
+        "--out", generatedDetagMain.get().asFile.absolutePath
+    )
+}
+
+sourceSets {
+    main {
+        // Human-written Detag source files. IntelliJ should treat this as a source root.
+        // Gradle's Java compiler will still only compile .java files directly from sourceSets,
+        // so the .tjava files are not compiled directly.
+        java.srcDir("src/main/tjava")
+    }
+}
+
+tasks.named<JavaCompile>("compileJava") {
+    dependsOn(detagMain)
+
+    // Compiler input generated from src/main/tjava.
+    // Do not add this directory to sourceSets, or IntelliJ will see duplicate classes:
+    // MyClass.tjava + build/generated/.../MyClass.java.
+    source(generatedDetagMain)
 }
 
 val libsDir = layout.buildDirectory.dir("libs")
diff --git a/src/main/java/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.java b/src/main/tjava/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.tjava
similarity index 79%
rename from src/main/java/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.java
rename to src/main/tjava/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.tjava
index d833b14..5658e8a 100644
--- a/src/main/java/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.java
+++ b/src/main/tjava/com/r35157/nenjim/hubd/impl/ref/ContextManagerImpl.tjava
@@ -2,7 +2,6 @@ package com.r35157.nenjim.hubd.impl.ref;
 
 import com.r35157.nenjim.hubd.ctx.Context;
 import com.r35157.nenjim.hubd.ctx.ContextManager;
-import com.r35157.nenjim.valuetypes.ctx.ContextId;
 
 import java.util.Set;
 
@@ -17,12 +16,12 @@ public class ContextManagerImpl implements ContextManager {
     }
 
     @Override
-    public Context get(ContextId contextId) {
+    public Context get(ΩContextIdΩ contextId) {
         return null;
     }
 
     @Override
-    public Set<ContextId> getList() {
+    public Set<ΩContextIdΩ> getList() {
         return Set.of();
     }