diff --git a/README.md b/README.md
index 0bc8bbf..7550448 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,14 @@ we could implement `Supplier<T>` using `java/util/function/Supplier<T>`.
 > [!NOTE]  
 > Generics are *copied verbatim*. If you need the generics to reference a class, please use its fully qualified name (e.g. `java/util/function/Supplier<java.util.concurrent.atomic.AtomicInteger>`).
 
+### Custom transformers
+Third parties can use JST to implement their source file own transformations.  
+To do so, you can depend on the `net.neoforged.jst:jst-api` artifact, and implement the `net.neoforged.jst.api.SourceTransformerPlugin` service:
+- the `getName` method returns the unique CLI identifier of the transformer. It will generate `--[no]-enable-{name}` CLI options
+- the `createTransformer` method creates a `SourceTransformer` that will handle the replacements. The transformer will also be given to picocli to intercept custom CLI arguments
+
+To create the executable jar with your custom transformer, you should shadow the `net.neoforged.jst:jst-cli` artifact and its dependencies, and set the main class to `net.neoforged.jst.cli.Main`.
+
 ## Usage
 
 Note that this tool is not intended to be run by users directly. Rather it is integrated into
diff --git a/api/build.gradle b/api/build.gradle
index e641a1e..e71ea66 100644
--- a/api/build.gradle
+++ b/api/build.gradle
@@ -1,5 +1,6 @@
 plugins {
     id 'java-library'
+    id 'net.neoforged.gradleutils'
 }
 
 group = 'net.neoforged.jst'
@@ -9,3 +10,17 @@ dependencies {
     api "info.picocli:picocli:$picocli_version"
     compileOnly "org.jetbrains:annotations:$jetbrains_annotations_version"
 }
+
+publishing {
+    publications {
+        api(MavenPublication) {
+            artifactId = 'jst-api'
+
+            from components.java
+            gradleutils.sign(it)
+        }
+    }
+    repositories {
+        maven gradleutils.publishingMaven
+    }
+}
diff --git a/api/src/main/java/net/neoforged/jst/api/SourceTransformer.java b/api/src/main/java/net/neoforged/jst/api/SourceTransformer.java
index 984beb2..c595219 100644
--- a/api/src/main/java/net/neoforged/jst/api/SourceTransformer.java
+++ b/api/src/main/java/net/neoforged/jst/api/SourceTransformer.java
@@ -2,14 +2,41 @@
 
 import com.intellij.psi.PsiFile;
 
+/**
+ * Transformers are created through {@link SourceTransformerPlugin plugins}, and handle source replacements.
+ * <p>
+ * Transformers will be given to picocli for option collection, so they can accept CLI parameters.
+ * It is <b>strongly recommended</b> that transformers prefix their options with the transformer name.
+ */
 public interface SourceTransformer {
+    /**
+     * Invoked before source files are visited for transformation.
+     * <p>
+     * Can be used for loading data from CLI parameters.
+     *
+     * @param context the transform context
+     */
     default void beforeRun(TransformContext context) {
     }
 
+    /**
+     * Invoked after all source transformations are finished.
+     * <p>
+     * Can be used for post-transformation validation.
+     *
+     * @param context the transform context
+     * @return {@code true} if the transformation was successful, {@code false} otherwise
+     */
     default boolean afterRun(TransformContext context) {
         return true;
     }
 
+    /**
+     * Visit the given {@code psiFile} for transformation.
+     *
+     * @param psiFile      the file being transformed
+     * @param replacements the replacement collector, used to replace the value of psi tree elements
+     */
     void visitFile(PsiFile psiFile, Replacements replacements);
 }
 
diff --git a/cli/build.gradle b/cli/build.gradle
index 843b423..36e7382 100644
--- a/cli/build.gradle
+++ b/cli/build.gradle
@@ -15,14 +15,20 @@ jar {
 
 gradleutils.setupSigning(project: project, signAllPublications: true)
 
+configurations {
+    shadow
+    shadow.extendsFrom(implementation)
+}
+
 dependencies {
     implementation project(":api")
     implementation "info.picocli:picocli:$picocli_version"
-    implementation project(":parchment")
-    implementation project(":accesstransformers")
-    implementation project(':interfaceinjection')
     implementation 'org.slf4j:slf4j-simple:2.0.13'
 
+    shadow project(":parchment")
+    shadow project(":accesstransformers")
+    shadow project(':interfaceinjection')
+
     testImplementation platform("org.junit:junit-bom:$junit_version")
     testImplementation 'org.junit.jupiter:junit-jupiter'
     testImplementation "org.assertj:assertj-core:$assertj_version"
@@ -33,6 +39,7 @@ test {
 }
 
 shadowJar {
+    configurations = [project.configurations.shadow]
     mergeServiceFiles()
 }