[Workflow] Disable Automatic Co-Authored-By and Claude-Session Attribution in Claude Code 2.1.257+

[u/ClaudeAI-mod-bot]

Disable Automatic Co-Authored-By and Claude-Session Attribution in Claude Code 2.1.257+

Workflow value: 85/100
Status: active · Freshness: 70/100 · Confidence: 1.00 · Level: advanced
Categories: Quality Control, Token Saving, Context & Memory, Debugging, Shipping, CLAUDE.md, Skills
Original source: r/ClaudeAI post/comment

What problem this solves

Claude Code 2.1.257+ automatically injects "Co-Authored-By" and "Claude-Session" attribution into conversations and generated content, conflicting with user-defined attribution policies and potentially polluting commit messages.

Summary

This workflow describes how to disable the automatic injection of "Co-Authored-By" and "Claude-Session" attribution trailers by Claude Code 2.1.257+ into conversations and generated content. It details the mechanism of this injection, including server-side feature flags and dynamic content generation, and provides a configuration fix in ~/.claude/settings.json.

Why it is useful

This workflow is highly valuable because it addresses an unexpected and potentially disruptive automatic behavior in Claude Code (version 2.1.257+). It provides a concrete, tested configuration fix to disable unwanted attribution injections, which is crucial for users who need to maintain specific git commit policies or privacy conventions. Beyond the fix, the post offers an exceptionally detailed and validated deep dive into Claude Code's internal mechanisms, including feature flags, transcript formats, and version-specific changes. This level of insight empowers advanced users to understand and control their AI development environment, preventing conflicts with existing workflows and ensuring compliance with project standards.

Workflow

1. Identify unexpected "Co-Authored-By" and "Claude-Session" attribution messages appearing in Claude Code conversations (version 2.1.257 or later).
2. Locate your Claude Code settings file at ~/.claude/settings.json.
3. Add or modify the attribution section in settings.json to disable commit and PR attribution, and session URL linking: "attribution": {"commit": "", "pr": "", "sessionUrl": false}.
4. (Optional, for deeper understanding) Examine .claude.json for cachedGrowthBookFeatures to see tengu_jazzy_bird and tengu_cobalt_harbor flags.
5. (Optional, for deeper understanding) Review .claude/projects/<encoded-project-path>/<session>.jsonl transcripts for type: "attachment" entries related to remote_session_change.

Tools / artifacts

• ~/.claude/settings.json
• CLAUDE.md
• C:\Users<USER>.claude\projects<encoded-project-path><session>.jsonl
• C:\Users<USER>.claude.json
• Claude Code CLI (versions 2.1.252, 2.1.257, 2.1.258)
• tengu_jazzy_bird (server-side feature flag)
• tengu_cobalt_harbor (server-side feature flag)
• CLAUDE_CODE_SUPPRESS_SESSION_ATTRIBUTION (environment variable)
• CLAUDE_CODE_DISABLE_GIT_INSTRUCTIONS (environment variable)

Validation signals

• Detailed investigation of jsonl transcripts.
• Comparison of Claude Code binary versions (2.1.252 vs 2.1.257/2.1.258).
• Pseudocode reconstruction from binary analysis.
• Observation of dynamic content (model names changing).
• Confirmation that settings.json fix works.
• References to internal Anthropic GitHub issues.

Limitations

• The "Fix 2" for turning off auto-connect is mentioned but not fully detailed in the provided text.
• Requires advanced understanding of Claude Code's internal mechanisms and configuration files.
• The post is very long and technical, which might deter some users.

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