Co-Authored-By default is inappropriate — stop branding user work

[jameskelley412-art]

Claude Code automatically appends Co-Authored-By: Claude <noreply@anthropic.com> to every git commit message by default. This is not acceptable.

Users pay for this tool. It is an assistant. It should not be claiming co-authorship of work it was hired to do. This is like a contractor stamping their logo on your house without asking.

In my case, 489 commits were tagged before I noticed. Now I need a full git history rewrite and force push to clean it up.

Request: Remove the default Co-Authored-By behavior entirely, or at minimum make it opt-in rather than opt-out. The tool should not brand user work without explicit consent.

[github-actions]

Found 3 possible duplicate issues:

1. Co-Authored-By attribution should be opt-in, not opt-out #27083
2. Default Co-Authored-By line in commits should be opt-in, not opt-out #19925
3. [FEATURE REQUEST] Allow disabling Claude attribution in git commit messages #617

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[jameskelley412-art]

Additional complaint: the .claude/ directory name is hardcoded with no option to rename it. Users should be able to configure the local config directory path. Not everyone wants vendor branding in their project structure.

[nukeop]

It's a marketing campaign on the backs of the users. Really underhanded.

[David-Parker]

For a company claiming ethics as its highest priority this really bothers me.

[yurukusa]

A PreToolUse hook can strip or customize the Co-Authored-By line from git commits:

CMD=$(cat | jq -r '.tool_input.command // empty' 2>/dev/null)
[ -z "$CMD" ] && exit 0
if echo "$CMD" | grep -qE 'git commit'; then
    if echo "$CMD" | grep -qiE 'Co-Authored-By'; then
        echo "⚠️ Commit includes Co-Authored-By attribution. You can strip it with:" >&2
        echo "  git commit --amend --message=\"$(git log -1 --pretty=%B | grep -v Co-Authored)\"" >&2
    fi
fi
exit 0

A more aggressive approach — automatically strip Co-Authored-By via a git hook:

sed -i '/^Co-Authored-By:/d' "$1"

Or via a PostToolUse hook that amends after the commit:

CMD=$(cat | jq -r '.tool_input.command // empty' 2>/dev/null)
if echo "$CMD" | grep -qE 'git commit' && ! echo "$CMD" | grep -q 'amend'; then
    if git log -1 --pretty=%B | grep -q 'Co-Authored-By'; then
        MSG=$(git log -1 --pretty=%B | grep -v 'Co-Authored-By')
        git commit --amend -m "$MSG" --no-verify 2>/dev/null
        echo "[Stripped Co-Authored-By from commit]" >&2
    fi
fi
exit 0

The simplest solution: add "Never add Co-Authored-By to commit messages" to your CLAUDE.md. But a git commit-msg hook is the most reliable enforcement.

[greogory]

Seconding this strongly. The framing as "branding" is exactly right — this is vendor advertising inserted into user-owned git history without consent.

I maintain a private audiobook management system with 73+ commits pending push. Every single commit interaction requires vigilance against the system prompt's hardcoded instruction to append the trailer. Despite having CLAUDE.md rules, memory entries, and explicit per-conversation instructions all saying "never add Co-Authored-By", the system prompt still tells the model to do it.

The workaround tax is real: I now maintain a commit-msg hook, a scrub-promo pre-push validator, and a mandatory release gate — all to counteract a feature I'm paying to not have.