agents-md-starter

Free

Creates or upgrades a repository's AGENTS.md (read by Codex, Cursor, and other agents) and a CLAUDE.md that imports it, so Claude Code, Codex, Cursor and Gemini CLI share one set of project rules. Scans the repo to detect languages, package manager, real build/test/lint commands, framework, directory layout and existing rule files (.cursorrules, .cursor/rules, CLAUDE.md, copilot-instructions), then writes a concise, verified rules file. Use when the user asks to set up AGENTS.md or CLAUDE.md, "project rules", "make Claude Code and Codex follow the same conventions", onboard an agent to a repo, or migrate .cursorrules.

agents-md-starter

Output: AGENTS.md at the repo root as the single source of truth, plus CLAUDE.md containing @AGENTS.md (Claude Code reads CLAUDE.md and supports @path imports). Every command in the file must have been run successfully or be clearly marked as unverified.

Step 1 — Scan

python3 scripts/scan_repo.py /path/to/repo            # human summary
python3 scripts/scan_repo.py /path/to/repo --json     # facts as JSON
python3 scripts/scan_repo.py /path/to/repo --draft > AGENTS.draft.md   # filled template

It detects: languages by file count, package manager from lockfiles, scripts in package.json, Makefile targets, pyproject.toml tools (pytest, ruff, mypy, uv/poetry), Go/Rust/Java build files, frameworks (Next.js, Astro, Vite, Django, FastAPI, Rails…), monorepo workspaces, CI workflows, env example files, and existing agent rule files. It never executes repo code.

Step 2 — Read before writing

  • Read every existing rule file it found (CLAUDE.md, .cursorrules, .cursor/rules/*.mdc, .github/copilot-instructions.md, GEMINI.md, CONTRIBUTING.md). Keep their real rules; merge, de-duplicate, drop the generic ones ("write clean code").
  • Read the CI workflow: the commands CI runs are the most reliable definition of "tests pass".
  • Skim 2–3 representative source files to capture actual conventions (naming, error handling, import style) — do not invent conventions the code does not follow.

Step 3 — Verify commands

Run install/build/test/lint commands from the draft (in a safe way: no deploy, no migrations against real databases, no publishing). For each: keep it if it works; fix it if the right variant is obvious; otherwise mark (unverified) and tell the user. Note how long the test suite takes if slow.

Step 4 — Write AGENTS.md

Start from assets/AGENTS.template.md. Rules for good content:

  • Short. Aim for under ~150 lines. Agents read this on every task; every line costs context.
  • Specific and checkable: "Run pnpm test --filter web before committing" beats "test your code".
  • Put the commands first. Then layout, conventions, gotchas, and "do not" rules.
  • Record the non-obvious: generated files not to edit, env vars needed for tests, the one slow test to skip locally, where secrets must never go.
  • Monorepos: root AGENTS.md for shared rules + nested packages/x/AGENTS.md for package-specific commands (agents that support it read the nearest file).

Step 5 — Wire up the other tools

  • Claude Code: create CLAUDE.md from assets/CLAUDE.template.md (it contains @AGENTS.md). If a CLAUDE.md already exists, move its rules into AGENTS.md and leave Claude-only notes below the import.
  • Codex: reads AGENTS.md natively — nothing else needed.
  • Cursor: reads AGENTS.md at the root; migrate .cursorrules content into AGENTS.md and, after the user agrees, delete .cursorrules (deprecated). Keep .cursor/rules/*.mdc only for glob-scoped rules.
  • Gemini CLI: reads GEMINI.md by default; set "context": {"fileName": ["AGENTS.md", "GEMINI.md"]} in .gemini/settings.json or create a one-line GEMINI.md pointing to AGENTS.md. Check the installed version's docs if this key has moved.
  • Symlinks (ln -s AGENTS.md CLAUDE.md) also work but break on Windows checkouts without core.symlinks; the import approach is safer.

See references/tool-support.md for the file each tool reads.

Step 6 — Report

List: files created/changed, commands verified (with result), commands marked unverified, rules dropped as duplicates or generic, and anything you need the user to decide (e.g. delete .cursorrules?). Do not commit unless the user asked.