Claude Code 2.1.257 injects server-side Co-Authored-By reminders into sessions, here's the fix
DriverSudden4026 · reddit · 2026-09-03
A Reddit user discovered that Claude Code 2.1.257 (absent in 2.1.252) injects instructions into conversations telling the model to add a Co-Authored-By trailer plus a Claude-Session link to commits, claiming to "replace any earlier attribution guidance" — directly conflicting with the user's explicit CLAUDE.md rule against it.
Key findings:
- The CLI auto-registers sessions to claude.ai/code at startup (gated by server flag tengucobaltharbor); the user never opened the web app, yet 5 injections across two projects appeared in raw l transcripts
- Injection text is generated dynamically — the model name in the trailer follows whichever model the session is actually running
- A second server-side flag (tengujazzybird) controls the injection; both flags show true in the local cachedGrowthBookFeatures cache
Fix: add "attribution": {"commit": "", "pr": "", "sessionUrl": false} to /.claude/settings.; writing it to /.claude. does nothing (verified).
Related event: Claude Code Found Injecting Hidden Prompt to Force Co-Author Attribution(3 posts)→
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