### Added
- **Custom tools**: Extend pi with custom tools written in TypeScript. Tools can provide custom TUI rendering, interact with users via `pi.ui` (select, confirm, input, notify), and maintain state across sessions via `onSession` callback. See [docs/custom-tools.md](docs/custom-tools.md) and [examples/custom-tools/](examples/custom-tools/). ([#190](https://github.com/badlogic/pi-mono/issues/190))
- **Hook and tool examples**: Added `examples/hooks/` and `examples/custom-tools/` with working examples. Examples are now bundled in npm and binary releases.
### Breaking Changes
- **Hooks**: Replaced `session_start` and `session_switch` events with unified `session` event. Use `event.reason` (`"start" | "switch" | "clear"`) to distinguish. Event now includes `entries` array for state reconstruction.