Kotlin Toolchain Plugin Authoring

Local plugins are the official escape hatch from declarative YAML: a jvm/amper-plugin module shipping task actions, settings, and generated sources/resources alongside your project. Code patterns to adapt are in references/examples.md.

When to write a plugin

Write one when you need:

• A build-time step a library's workflow expects (code generation, schema compilation, resource transformation, version stamping).
• Custom verification wired into the build (pre-release checks, schema validation, contract tests).
• A build-time value published into the JAR classpath or downstream tasks — the closest analog to Gradle's project.version.
• A named CLI command for a repeated workflow (./kotlin do release).

Don't write one when module.yaml already covers it (dependencies, JDK provisioning, source layouts, basic packaging), and never to reuse a Gradle plugin — the Kotlin Toolchain cannot consume them.