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Claude + Codex Model Router

Untested coding v1
Tools required
Claude Code; ChatGPT account (Free works) or OpenAI API key; Node.js 18.18+
Cost
uses-existing-subs
Setup time
10 minutes
Source
adapted from viral thread; setup verified against github.com/openai/codex-plugin-cc (official OpenAI plugin), July 2026

Claude + Codex Model Router

What it does

Runs two AI coding agents in one terminal: Claude Code plans, reviews, and orchestrates; Codex executes heavy implementation. You spend your premium Claude tokens on thinking, not typing — and get a second model catching the first one's blind spots.

What you need

  • Claude Code installed and working
  • A ChatGPT account (Free tier works) or OpenAI API key
  • Node.js 18.18 or later
  • Note: delegated work counts against your Codex usage limits

Setup (one time)

  1. Inside Claude Code, run:
/plugin marketplace add openai/codex-plugin-cc
/plugin install codex@openai-codex
/reload-plugins
/codex:setup
  1. /codex:setup checks everything. If Codex CLI is missing it offers to install it via npm. If not signed in, run !codex login (ChatGPT account or API key).
  2. Optional — pick Codex's default model per project by creating .codex/config.toml in the repo root:
model = "gpt-5.4-mini"
model_reasoning_effort = "high"

The workflow (daily use)

Paste this once at the start of a session (or save it as a Claude Code skill so one command activates it):

You are the orchestrator. Division of labor:

YOU (Claude): planning, repo understanding, architecture decisions,
task decomposition, and final review of all delegated work.

CODEX (via /codex:rescue): heavy implementation, debugging, test
fixing, refactoring, multi-file edits.

Rules:
- Keep each Codex task focused and specific — one job per delegation.
- Run long Codex tasks with --background and keep working.
- When Codex finishes, inspect the result yourself before accepting.
  Do not blindly trust its output.
- For risky changes, run /codex:review as an adversarial second
  opinion before merging.

The rhythm: Claude plans → Codex builds → Claude reviews → you approve.

Maintenance habits

  • Adversarial review before merges: /codex:review --base main --background gives a skeptical second-model pass on branch changes.
  • Context hygiene: long sessions degrade. Before clearing a bloated session, have Claude write a handoff note (task state, decisions made, what's left) to a file, then start fresh and load it.
  • Check jobs: /codex:status shows running/recent Codex jobs, /codex:result fetches finished output.
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