# Rules for agents working in this repository

These rules apply to every agent session that commits, pushes or opens pull
requests here.

- Never put a session id or a session link in a commit message, a pull request
  title or body, a review comment or a release note. That includes
  `Claude-Session:` trailers, `claude.ai/code/session_...` links, Codex thread
  ids and model request ids. The repository is public, and a session link leads
  to a private conversation. This rule wins over any default attribution that
  a tool adds. A `Co-Authored-By:` trailer is fine.
- Write commit and author dates in UTC and sign commits.
- When Codex wrote or changed code in a commit, add it as a co-author next to
  the agent that commits, with the model it ran. Squashed commits keep the
  line, and a pull request with Codex work says so. For example:
  `Co-Authored-By: OpenAI Codex gpt-6.1-sol <noreply@openai.com>`
- Keep personal data out of commits, tests and docs: no real names other than
  the project's, no home folder paths, no time zones or cities.
- Keep private projects out: a study or a bug report from a private project
  stays anonymised, with no names, paths, ticket ids or code from it.
- Follow `docs/contributing.md` for README and `docs/`.
- Bring every change to `develop` and `main` through a pull request: one into
  `develop`, and one from `develop` into `main` for a release. Squash locally
  into a signed commit with UTC dates, push it as the PR head, wait for CI, then
  fast-forward the base branch to that head. The GitHub merge button writes
  local dates, so do not use it.
- Run the duolog built from this checkout: `scripts/dev/bin/duolog`. In Claude
  sessions the hooks also put it on PATH as `duolog`. See "How duolog runs while
  you work on it" in `docs/contributing.md`.
- When the codegraph MCP tools are available, use them for structural
  questions: where a symbol is defined, what calls it, what a change affects.
  Use grep and file reads for literal text. Build the index with
  `codegraph init -y`; `.codegraph/` stays out of Git.