claude-codex

Smart size-based routing: Claude implements small changes (<=2 files, <=30 lines), Codex implements large changes, code-reviewer agent reviews all. Best for: executing a plan or task where you want automatic routing by complexity. Triggers on: /execute-codex, execute plan, implement with routing, run the plan.

Full TDD with smart routing: Claude writes tests first, Codex audits tests, then routes implementation by size (Claude small / Codex large), code-reviewer reviews. Best for: TDD on larger tasks where Codex should handle heavy implementation. Triggers on: /tdd-execute-codex, TDD with routing, test-driven execute, TDD large feature.

Claude implements code changes, Codex reviews via MCP with structured APPROVED/WARNING/BLOCKED verdicts. Best for: straightforward implementation where you want an external Codex review. Triggers on: /claude-codex, implement and review, build with Codex review, code with external review.

Create a detailed implementation plan with Opus-level reasoning, then Codex audits it for correctness, completeness, and security in a loop until approved. Best for: planning before coding — never modifies production code. Triggers on: /plan-codex, plan a feature, create implementation plan, design a system, architect this.

Full TDD workflow: Claude writes tests first (RED), Codex audits tests, Claude implements (GREEN), refactors (IMPROVE), Codex reviews final implementation. Best for: test-driven development where you want Codex reviewing both tests and code. Triggers on: /tdd-claude-codex, TDD with review, test-driven implement, tests first then implement.

How to use OpenAI Codex via MCP tools for code generation, plan review, and collaborative implementation loops. Use when calling Codex for implementation, review, or any cross-model collaboration.