[Feature Request] Cross-file consistency: auto-grep repo after fixing a pattern

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single report
• [x] I am using the latest version of Claude Code

Summary

Follow-up to #45731 (cross-file consistency) and #45738 (Pattern 3).

When Claude fixes a bug in one file, it does not check the rest of the repository for the same pattern. This happened 3 times in a single session for 3 different bug classes:

• Fixed path traversal in file A, same vulnerability existed in file B
• Removed unused import in file A, same unused import existed in file B
• Fixed error handling in layer 3, same broken handling in layer 2

Each time Claude wrote a reflection saying 'next time I will check both layers.' Each time it did not.

Proposed Solution

After every bug fix, automatically run:

grep -rn "FIXED_PATTERN" --include="*.ext" .

If the same pattern exists in other files → fix all occurrences in the same commit. One-file fix when the pattern is multi-file = half-work.

This could be a PostToolUse hook on file writes: extract the changed pattern, grep the repo, warn if found elsewhere.

Why This Matters

150+ review threads in #45731 — many were the exact same bug class appearing in parallel files. Cross-file grep before commit would have caught these in round 1 instead of round 5.

Environment

• Claude Code CLI (latest)
• Model: Claude Opus (Max plan)
• macOS