---
name: pi-extension-lifecycle
description: Pi extension lifecycle and registration patterns. Use when adding or reviewing extension tools, commands, resources, providers, event handlers, session hooks, or context-sensitive Pi API usage.
---

# pi-extension-lifecycle

Use this skill when working on Pi extension registration or lifecycle behavior.

## Source patterns distilled

- Pi core: `source/pi-mono/packages/coding-agent/src/core/extensions/types.ts`, `loader.ts`, `runner.ts`
- Pi examples: `source/pi-mono/packages/coding-agent/examples/extensions/`
- pi-crew extension entry: `src/extension/register.ts`, `src/extension/registration/*.ts`

## Rules

- Register tools, commands, shortcuts, widgets, providers, and event handlers from the extension factory or lifecycle callbacks.
- Tool definitions should use a TypeBox schema and an `execute(toolCallId, params, signal, onUpdate, ctx)` handler.
- Use fresh `ExtensionContext`/`ExtensionCommandContext` after session replacement (`newSession`, `fork`, `switchSession`, `reload`). Do not retain old context references for later work.
- For session-scoped work, derive session identity from `ctx.sessionManager.getSessionId()` and pass it into pi-crew `TeamContext`.
- Prefer small registration modules under `src/extension/registration/`; keep `index.ts` minimal.
- Clean up intervals, event subscriptions, child processes, and watchers on session switch/shutdown.
- Wrap optional Pi API hooks in compatibility checks/try-catch when supporting older Pi versions.

## Anti-patterns

- Do not use stale context objects after session switch.
- Do not register duplicate tool/command names and assume override behavior.
- Do not perform blocking filesystem or network work inside extension render callbacks.
- Do not add hardcoded global keybindings without config or collision review.

## Verification

```bash
cd pi-crew
npx tsc --noEmit
npm test
```