- Add blocked todo status and optional blocker attribute to todo items.
- Update RPC client and worker serialization logic to support todo blockers.
- Add test coverage for parsing session state with blocked todos.
- Updated `ThinkingConfig` and related types to model effort-based thinking settings with optional defaults and routing metadata.
- Added a dedicated parser for `model.thinking` payloads to validate efforts and normalize new optional thinking fields.
- Extended protocol tests to verify effort-based thinking data is parsed correctly and unknown efforts are rejected.
- Added `_optional_str_list` to normalize `systemPrompt` payloads into a tuple when absent, a bare string, or a string array, and to reject invalid shapes.
- Updated `SessionState` to hold `system_prompt` as a tuple and to parse daemon payloads with the new helper in `parse_session_state`.
- Extended protocol tests to verify array and legacy string parsing, default empty tuple behavior, and invalid `systemPrompt` values.
- Added host tool execution framework with HostTool, HostToolContext, and host_tool() factory for custom tool integration.
- Added RpcConcurrencyError exception and _PromptLifecycleCoordinator to enforce single-flight constraint on prompt lifecycle methods.
- Enhanced JSON parsing with 10 validation helpers and enum frozensets for safe field extraction with detailed error messages.
- Replaced manual event/error list management with _BoundedHistory for bounded-size history with offset tracking.
- Added deep JSON cloning to prevent external mutations of stored payloads and improved UTF-8 error handling in subprocess stderr.
- Added custom_tools parameter to RpcClient and set_custom_tools() method for runtime tool registration.
- Added error handling callbacks (on_protocol_error, on_listener_error) and error history tracking (protocol_errors, listener_errors properties) for RPC failures.
- Added max_event_history and max_stderr_chunks parameters to bound retained history in long-lived hosts, preventing unbounded memory growth.
- Added assistant_text_with_thinking() and message_text_with_thinking() helper functions for backward compatibility with thinking block inclusion.
- Improved error correlation for id-less parse/unknown-command failures to waiting requests and changed prompt scheduling failures to raise instead of timing out.
- Refactored event dispatch to _dispatch_listeners() with exception handling and error recording for robust listener failure management.
- Added typed event listeners and granular event handling for all RPC notification types.
- Added set_todos RPC command and todoPhases session state field for todo phase management.
- Added RpcClient initialization parameters (thinking, tools, no_session, rpc_defaults) for startup configuration.
- Added install_headless_ui() method and todo management methods (get_todos, set_todos, clear_todos).
- Added TodoItem and TodoPhase dataclasses with parser functions for structured todo representation.
- Added RPC mode behavior: disables session title generation by default and resets workflow settings to built-in defaults.
- Added RpcClient class with subprocess-based RPC communication, thread-safe request/response handling, and 30+ public methods for agent operations.
- Defined 65+ public API symbols including protocol types, dataclasses, parser functions, and custom exception types for RPC communication.
- Implemented event listener system with on_event, on_ui_request, and on_extension_error callbacks for asynchronous RPC event handling.
- Added comprehensive test suite with integration tests for RpcClient and unit tests for protocol parsing functions.
- Configured Python package with setuptools, PEP 561 type hints support, and documentation for usage and API reference.
Wolfgang Schoenberger