Files
ai-development-scaffold/docs/lean-setup.md
J-BlandandClaude Sonnet 5.5 d45d4bec97 feat: lean default install for Claude Code and Codex with safe installer
Adds a marked global rules block, project AGENTS.md/CLAUDE.md template, an on-demand
lean-review skill, a dry-run-first stdlib installer with backups, and tests using temp
homes. README quick start no longer moves ~/.claude; legacy library stays opt-in.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
2026-09-30 13:43:26 -04:00

3.3 KiB

Lean setup

Default install is small: a marked rules block in the user-level instruction files, an optional lean-review skill for Claude, and a project template. The legacy library (.claude/, .agents/, .codex/) is untouched and stays opt-in.

Install

python3 scripts/lean-install.py global                 # dry-run: shows what would change
python3 scripts/lean-install.py global --apply         # ~/.claude/CLAUDE.md, $CODEX_HOME/AGENTS.md, lean-review skill
python3 scripts/lean-install.py project /path/to/repo --apply   # AGENTS.md + CLAUDE.md (@AGENTS.md)
python3 scripts/lean-install.py uninstall --apply      # remove only the marked block

Options: --claude-home, --codex-home (defaults $CLAUDE_CONFIG_DIR/~/.claude, $CODEX_HOME/~/.codex), --skip-claude, --skip-codex, --skip-skill, --force.

Safety: dry-run unless --apply; the whole plan is validated before any write; an existing file is changed only by adding or replacing the marked block, after a *.bak-<timestamp> copy (never overwriting an earlier backup); symlinked targets, non-UTF-8 files, malformed markers and missing homes are refused; differing skill/project files need --force; settings, config.toml and auth.json are never read or written; no shell rc edits. Restore by copying a backup back over the file.

Codex reads $CODEX_HOME/AGENTS.override.md before AGENTS.md; an override file makes the installed global block inactive.

Optional full library

Copy pieces by hand rather than wholesale: pick agents from .claude/agents/ (or .codex/agents/), skills from .agents/skills/, and merge hook entries from .claude/settings.json into your own settings after backing yours up. Hooks there reference ~/.claude/hooks/, so only enable them once the scripts are copied there. Never replace ~/.claude or its credentials.

Sources and decisions

Official: Claude Code best practices, Codex AGENTS.md guide (redirects to learn.chatgpt.com/docs/agent-configuration/agents-md). Comparison material: Migration Accelerator CLAUDE.md (public GitHub sample J-Bland/migration-accelerator; the private original on git.kinec.tech was unavailable, so this is a mirror and may differ) and HyperFactory AGENTS.md / diff-reviewer.

Adopted:

  • Compact always-loaded files; detail on demand via skills and links (official; MA/HF both enforce a size budget).
  • Verification the agent can run, reported with real output (Claude best practices).
  • Explore/plan only for substantive changes (Claude best practices).
  • One shared AGENTS.md, with CLAUDE.md importing it via @AGENTS.md; global Codex file lives in the actual CODEX_HOME, project files layer root-down (Codex guide).
  • Evidence rule and one consolidated diff review: a finding needs a concrete failing input and a failed refutation, existing guards are checked first (HyperFactory diff-reviewer).
  • Security review only when the diff warrants it.

Rejected: mandatory refactor agent after every green; stop-hook loops; full role inventories; xhigh/1M-context defaults; enabling every MCP or LSP plugin; broad global permissions; hooks pointing at paths that may not exist; multi-model review loops; changing model or provider settings.