DSH plugin development

A DSH plugin is a cordis plugin: an ES module exporting apply(ctx, config), packaged with a dsh.bundle.patch declaration so dsh plugin add promotes it into a profile's layer stack.

When to use

• Adding a tool the model can call (ctx.tools.register(defineTool(...))).
• Hooking harness events (tools/pre-execute, agent/pre-step, session/event, ...).
• Providing a service (class X extends Service), an LLM adapter, or a user-facing surface (ctx.settings.register for a settings card, ctx.webServer.register for a route).
• Diagnosing a plugin that installs but never loads, or whose config is ignored.

Do not use for editing DSH itself, or for ~/.dsh/profiles/<p>/cordis.yml (always []; edit cordis.patch.yml instead).

Environment (verified)