codex-system

name	codex-system
description	Use to decide when to invoke the Codex CLI and how. Codex specializes in tight iterate-loops, small refactors, lint cycles, and test additions. Includes invocation patterns and anti-patterns.

codex-system

Send to Codex

• Small, well-scoped refactors with a clear acceptance check.
• Test additions for an existing module.
• Lint / typecheck loop until clean.
• Mechanical migrations (rename a symbol across the repo, swap an import).

Don't send to Codex

• Open-ended design.
• Ambiguous bug reports without a reproducer.
• Cross-module architectural changes.
• Anything where success criteria aren't writable in one sentence.

Invocation patterns

Basic

codex "Apply the tdd skill to add tests for src/foo/bar.ts. Stop when coverage of bar.ts ≥ 90%."

Pipe

git diff main...HEAD -- 'src/**' | codex "Run the lint loop on these changes; commit only after lint is clean."

Iterate loop

Give Codex a single acceptance command (pnpm test, cargo clippy -- -D warnings) and let it loop. Cap loop iterations via the five-attempt rule in .codex/AGENTS.md.

Pre-flight checklist

• Acceptance check is a one-liner that returns 0 / non-0.
• Scope is one or two files unless mechanical.
• No design decisions are left to Codex.

Anti-patterns

• Letting Codex pick the architecture.
• Skipping the lint loop because "it's just a small change".
• Committing without reading Codex's diff yourself.