# Cross-Model (Claude Code + Codex) Workflow

based on [claude-code-best-practice](https://github.com/shanraisshan/claude-code-best-practice) and [codex-cli-best-practice](https://github.com/shanraisshan/codex-cli-best-practice)

## Workflow

```
┌─────────────────────────────────────────────────────────────────────────┐
│              CROSS-MODEL CLAUDE CODE + CODEX WORKFLOW                   │
├─────────────────────────────────────────────────────────────────────────┤
│                                                                         │
│  STEP 1: PLAN                                          Claude Code      │
│  ─────────────                                         Opus 4.6         │
│  Open Claude Code in plan mode (Terminal 1).           Plan Mode        │
│  Claude interviews you via AskUserQuestion.                             │
│  Produces a phased plan with test gates.                                │
│                                                                         │
│  Output: plans/{feature-name}.md                                        │
│                                                                         │
│                              ▼                                          │
│                                                                         │
│  STEP 2: QA REVIEW                                     Codex CLI        │
│  ──────────────────                                    GPT-5.4          │
│  Open Codex CLI in another terminal (Terminal 2).                       │
│  Codex reviews plan against the actual codebase.                        │
│  Inserts intermediate phases ("Phase 2.5")                              │
│  with "Codex Finding" headings.                                         │
│  Adds to the plan — never rewrites original phases.                     │
│                                                                         │
│  Output: plans/{feature-name}.md (updated)                              │
│                                                                         │
│                              ▼                                          │
│                                                                         │
│  STEP 3: IMPLEMENT                                     Claude Code      │
│  ──────────────────                                    Opus 4.6         │
│  Start a new Claude Code session (Terminal 1).                          │
│  You implement phase-by-phase                                           │
│  with test gates at each phase.                                         │
│                                                                         │
│                              ▼                                          │
│                                                                         │
│  STEP 4: VERIFY                                        Codex CLI        │
│  ────────────────                                      GPT-5.4          │
│  Start a new Codex CLI session (Terminal 2).                            │
│  Codex verifies the implementation                                      │
│  against the plan.                                                      │
│                                                                         │
└─────────────────────────────────────────────────────────────────────────┘
```

## How cross-model workflow actually looks in production

![Cross-Model Workflow](assets/cross-model-workflow.png)

*Last Updated: 2026-03-06*