Claude Agent SDK (Python) v0.2.177

Summary

Version 0.2.177 of the Python Claude Agent SDK (2026-11-03) adds an on_failure option to HookMatcher and bundles Claude Code CLI 2.1.317.

Key points

• Install: pip install claude-agent-sdk==0.2.177.
• on_failure="block" on a HookMatcher blocks the action when the hook callback raises, returns None, or returns a value the CLI rejects. The default, "continue", treats a failure as "no decision", which lets the action run.
• It needs a CLI that supports the option. Connecting to an older CLI with on_failure="block" raises CLIConnectionError, so the guard cannot be lost silently.
• Bundled CLI: 2.1.317 (see the Claude Code 2.1.317 note).

Why it matters

Policy hooks (for example "never write outside this folder") can now fail closed, which is what a security control should do.