Claude Code adds a side-agent mod and fixes permission handling

Claude Code 2.1.287 introduces Mods, allowing plugins to change deeper agent behavior. Its built-in “You should know” mod uses a side agent to flag things the user or main agent may miss. The same release fixes permission-handling defects, including cases involving dangerous shell commands with redirected output and organization limits on a specially named MCP tool.

Anthropic · Oct 1, 2026

Why it matters

Existing users have concrete workflow changes and permission fixes to review before their next session.

More context

Try the released update with your existing Claude Code access. The built-in mod requires first-party sessions with telemetry enabled; evaluate it on a small task before relying on its suggestions. The release notes document how to enable it.

Keep in mind

A second agent is not a guarantee of correct review. The notes do not establish its incremental cost or reliability, and 1min has not tested the mod or independently verified the fixes.

Original read