### New Features
- Extensions and SDK callers can attach a `prepareArguments` hook to any tool definition, letting them normalize or migrate raw model arguments before schema validation. The built-in `edit` tool uses this to transparently support sessions created with the old single-edit schema. See [docs/extensions.md](docs/extensions.md)
- Extensions can customize the collapsed thinking block label via `ctx.ui.setHiddenThinkingLabel()`. See [examples/extensions/hidden-thinking-label.ts](examples/extensions/hidden-thinking-label.ts) ([#2673](https://github.com/badlogic/pi-mono/issues/2673))
### Breaking Changes
- `ModelRegistry` no longer has a public constructor. SDK callers and tests must use `ModelRegistry.create(authStorage, modelsJsonPath?)` for file-backed registries or `ModelRegistry.inMemory(authStorage)` for built-in-only registries. Direct `new ModelRegistry(...)` calls no longer compile.
### Added
- Added `ToolDefinition.prepareArguments` hook to prepare raw tool call arguments before schema validation, enabling compatibility shims for resumed sessions with outdated tool schemas
- Built-in `edit` tool now uses `prepareArguments` to silently fold legacy top-level `oldText`/`newText` into `edits[]` when resuming old sessions
- Added `ctx.ui.setHiddenThinkingLabel()` so extensions can customize the collapsed thinking label in interactive mode, with a no-op in RPC mode and a runnable example extension in `examples/extensions/hidden-thinking-label.ts` ([#2673](https://github.com/badlogic/pi-mono/issues/2673))
### Fixed
- Fixed extension-queued user messages to refresh the interactive pending-message list so messages submitted while a turn is active are no longer silently dropped ([#2674](https://github.com/badlogic/pi-mono/pull/2674) by [@mrexodia](https://github.com/mrexodia))
- Fixed monorepo `tsconfig.json` path mappings to resolve `@mariozechner/pi-ai` subpath exports to source files in development checkouts ([#2625](https://github.com/badlogic/pi-mono/pull/2625) by [@ferologics](https://github.com/ferologics))
- Fixed TUI cell size response handling to consume only exact `CSI 6 ; height ; width t` replies, so bare `Escape` is no longer swallowed while waiting for terminal image metadata ([#2661](https://github.com/badlogic/pi-mono/issues/2661))
- Fixed Kitty keyboard protocol keypad functional keys to normalize to logical digits, symbols, and navigation keys, so numpad input in terminals such as iTerm2 no longer inserts Private Use Area gibberish or gets ignored ([#2650](https://github.com/badlogic/pi-mono/issues/2650))