[BUG] Claude Code adds Co-Authored-By footer that links commits to unrelated GitHub account

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code adds Co-Authored-By footer that links commits to unrelated GitHub account

Description

Claude Code automatically appends Co-Authored-By: Claude Code <claude-code@anthropic.com> to all commit messages. This email address is registered on a public GitHub account (username: Karim13014) that is unrelated to Anthropic or the development organization.

As a result, all commits generated by Claude Code across multiple organizations are incorrectly attributed to this third-party GitHub account, creating false contributor attribution in git history and GitHub repository statistics.

Steps to Reproduce

1. Use Claude Code to generate and commit code changes
2. Observe commit message in git log or on GitHub
3. Notice the footer: Co-Authored-By: Claude Code <claude-code@anthropic.com>
4. Visit GitHub user profile: https://github.com/Karim13014
5. Check their contribution graph — it now shows contributions from unrelated organizations' repositories

Expected Behavior

• Claude Code commits should either:
• Use an @anthropic.com email address controlled by Anthropic, OR
• Make co-author attribution opt-in instead of default, OR
• Respect the includeCoAuthoredBy: false setting in settings.json and CLAUDE.md

Actual Behavior

• All Claude Code commits include the footer linking to the unrelated GitHub account
• User configuration settings (includeCoAuthoredBy: false) are ignored
• The footer persists even when explicitly instructed not to include it

Impact

• False attribution: External GitHub user appears as co-author on private company repositories
• Git history pollution: All generated commits are attributed to a third party
• Contributor stats skewed: Organizational contributor reports include unrelated accounts
• Cross-organization issue: Affects all companies/teams using Claude Code with this footer

Evidence

Example commit affected:

• Repository: https://github.com/albert-labs/albert-python
• Commit: 2bf5d6e8e021db40db925685483061e7caa3cd7e
• Shows: Karim13014 as co-author despite being generated by Claude Code for an internal team

Root Cause

The claude-code@anthropic.com email is registered on a public GitHub account (Karim13014). When GitHub parses the Co-Authored-By trailer in commit messages, it matches this email and links the commit to that account.

This is a system-level issue: GitHub's co-author parsing is functioning correctly, but Claude Code is using an email address that is not controlled or managed by Anthropic.

Suggested Solutions

Solution 1: Use Anthropic-controlled email

Change the default footer to use a real Anthropic email address:

Co-Authored-By: Claude Code <code@anthropic.com>

(or similar, managed by Anthropic)

Solution 2: Make attribution opt-in

Remove the co-author footer by default. Allow users to enable it in settings.json if they want:

{
  "git": {
    "includeCoAuthoredBy": true
  }
}

Solution 3: Respect configuration settings

Honor the includeCoAuthoredBy: false setting when explicitly set by the user in settings.json, CLAUDE.md, or inline instructions.

Environment

• Claude Code version: Latest (as of May 2026)
• Operating system: macOS / Linux / Windows (affects all platforms)
• Scope: System-wide issue affecting all Claude Code users

Related Issues

• #53259 — Co-Authored-By system prompt overrides CLAUDE.md, settings.json, and skill instructions
• #18253 — Attribution settings not honored
• #1653 — Incorrect Co-Author Attribution for Claude Code Commits to GitHub

Additional Context

This is affecting multiple organizations with public repositories. The issue creates unintended attribution that:

1. Violates the integrity of git commit history
2. Associates external users with internal code
3. Appears to give credit to an unrelated developer
4. Makes it impossible for organizations using Claude Code to maintain clean attribution records

A simple fix would be to either use an Anthropic-controlled email or make the attribution opt-in.

---

Workaround (temporary): Stop using the Co-Authored-By footer in commit messages and manually manage Claude Code attribution through other means (PR descriptions, commit body, etc.).

What Should Happen?

• Claude Code commits should either:
• Use an @anthropic.com email address controlled by Anthropic, OR
• Make co-author attribution opt-in instead of default, OR
• Respect the includeCoAuthoredBy: false setting in settings.json and CLAUDE.md

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Use Claude Code to generate and commit code changes
2. Observe commit message in git log or on GitHub
3. Notice the footer: Co-Authored-By: Claude Code <claude-code@anthropic.com>
4. Visit GitHub user profile: https://github.com/Karim13014
5. Check their contribution graph — it now shows contributions from unrelated organizations' repositories

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code v2.1.66

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_