Claude Agent Sdk Python 0.2.166

New Features

• Hook-specific output types: Added typed output classes and missing input fields for hooks, giving hook implementations precise type information instead of untyped dicts (#1331)
• SystemInitData TypedDict: The init system message payload is now fully typed via SystemInitData, along with nested types SystemInitMcpServer, SystemInitPlugin, SystemInitPluginError, and FastModeState/FastModeDisabledReason literals. Use cast(SystemInitData, msg.data) to access typed fields like capabilities, model, mcp_servers, and more (#1332)

Bug Fixes

• Fixed SandboxSettings.ignoreViolations type: Changed from a TypedDict with file/network keys to dict[str, list[str]] to match the CLI's actual schema - a map from command-pattern substring to violation-text substrings. The old type caused "file" and "network" to be interpreted as command patterns, and strict type checkers rejected the correct {"*": [...]} shape (#1380)

Internal/Other Changes

• Updated bundled Claude CLI to version 2.1.299

PyPI: https://pypi.org/project/claude-agent-sdk/0.2.166/

pip install claude-agent-sdk==0.2.166