Claudecodex

claudecodex — Run Claude Code with GPT-5.6 using your ChatGPT subscription

claudecodex lets you use Claude Code with OpenAI models — GPT-5.6
(Sol / Terra / Luna) as the engine — billed to your ChatGPT Plus/Pro
subscription through a local Codex proxy, without an Anthropic API key
or an OpenAI API key.

You keep the Claude Code agent workflow you like (file edits, terminal flow,
approvals, MCP servers, skills) but the model answering is GPT-5.6, running on
the ChatGPT subscription you already pay for instead of your Anthropic usage.

One-line install. Plain claude stays completely stock.

How it works

claudecodex launches the real Claude Code UI, points it at a local
Anthropic-compatible proxy on 127.0.0.1:18765, and the proxy forwards requests
to GPT-5.6 via Codex auth on your ChatGPT subscription:

Jump to: Install · Usage & model switching ·
Configuration · vs alternatives ·
Troubleshooting · FAQ: Claude Code without an Anthropic API key

Demo

*(8× speed — watch the full demo video)*

Why run Claude Code with OpenAI models?

- Claude Code UI + GPT models — the best agentic coding interface, driving
  OpenAI's strongest coding model (GPT-5.6 Sol at max reasoning effort).
- Uses the ChatGPT subscription you already have — no pay-per-token API
  bills; requests go through Codex auth on your Plus/Pro plan.
- Zero interference — a thin launcher that execs claude with
  process-local environment variables. Your normal claude command, login,
  settings, and Anthropic models are untouched.
- Full 372K context window — configured to GPT-5.6 Sol's real Codex
  context limit, so the context gauge and auto-compaction are accurate.
- Model switching built in — flip between Sol (best), Terra (mid), and
  Luna (fast/cheap) per launch or mid-session.

claudecodex is a thin…