Auto-suppress AI commit/PR attribution for Claude Code via a committed .claude/settings.json

[okinaka]

Context

AGENT.md is the canonical agent-instructions file (tracked in the repo). Per
CONTRIBUTING.md, contributors create a local symlink so their agent picks it up
(e.g. ln -s AGENT.md CLAUDE.md). The deliberately generic AGENT.md name — plus the
gitignored symlink names CLAUDE.md / GEMINI.md / COPILOT.md — shows the repo
targets multiple AI agents, not just Claude Code.

AGENT.md includes a rule that AI agents must not add Co-Authored-By trailers
(or "Generated with ..." lines) to commits — attribution stays limited to humans.

Problem 1 — attribution needs manual stripping every time

Claude Code adds a Co-Authored-By: Claude trailer by default, so contributors have
to remind it to strip the trailer on each commit. Repetitive and easy to miss.

Problem 2 — the rules only apply if you remembered to symlink

Claude Code loads CLAUDE.md, a gitignored symlink each contributor makes by hand.
Anyone who runs Claude Code without that step gets no project guidance at all —
AGENT.md never loads, so the no-attribution rule (and every other rule) silently
doesn't apply. The trailer is a visible symptom of this setup gap.

Idea

Commit a .claude/settings.json that suppresses attribution declaratively:

{
  "attribution": {
    "commit": "",
    "pr": ""
  }
}

Empty strings drop both the commit trailer and PR-description attribution. Notably,
.claude/settings.json is read independently of the CLAUDE.md symlink, so it fixes
attribution even for contributors who skipped the symlink (Problem 2).

Caveats:

• .claude is currently gitignored, so this needs a .gitignore exception
  (e.g. !.claude/settings.json), and it cuts against the "keep agent files local" convention.
• It's Claude-Code-specific. Since the repo deliberately supports multiple agents via
  the generic AGENT.md, this only covers Claude Code — other agents (Gemini, Copilot, ...)
  would still rely on the prose rule, and an equivalent setting may not exist in every environment.

Open questions

• Do we want to commit Claude-Code-specific config given the repo intentionally
  gitignores .claude and uses a tool-agnostic AGENT.md?
• Is per-tool config acceptable here, or should enforcement stay tool-agnostic?

Happy to open a PR if there's interest.

References

• Claude Code — Settings (Attribution settings): https://code.claude.com/docs/en/settings#attribution-settings
• Claude Code settings JSON schema: https://www.schemastore.org/claude-code-settings.json

[okinaka]

• refs: docs: adopt AGENTS.md standard #1225