Use your ChatGPT plan in Reason
Open Reason on the web or the Mac app
Sign in at reasonmachines.com, or download the Reason app for macOS from reasonmachines.com/download. Both open the same Sessions. Sending work to Reason needs a Pro or Max plan.
Sign in with ChatGPT
Open Settings › Models and, under Subscriptions, choose Sign in with ChatGPT, then sign in with your ChatGPT Plus, Pro or Business account. Reason then runs OpenAI models on your plan, and OpenAI bills it as part of that plan.
Connect your other plans and keys
In the same Subscriptions list, connect Claude (Pro or Max), Grok (SuperGrok or X Premium+) or GitHub Copilot too, and add API keys under API keys. Work on your own accounts is billed by that provider, not in Reason credits.
Pick the model per task
In the composer, choose the model for the Session. Each Session shows the model and account it ran on, so you can see which plan did the work.
Keep going at a limit
When the account a turn runs on hits its limit, Reason moves the turn to your other connected accounts for that provider, then to Reason credits if your workspace can pay, and says so in the conversation.
Where your ChatGPT plan works for coding
| Agent | ChatGPT plan? | From its docs |
|---|---|---|
| Codex | Yes | Sign in with ChatGPT for subscription access; Plus, Pro and Business get the CLI, IDE extension, web and iOS; Free and Go get the desktop app |
| Claude Code | No | Signs in with Claude plans, Claude Console or a cloud provider; Anthropic doesn't support routing it to non-Claude models through any gateway |
| Cursor's own agent | No | OpenAI: a ChatGPT subscription doesn't include API usage; use the Codex IDE extension inside Cursor instead |
| Codex extension in Cursor | Yes | OpenAI's own extension, signed in with ChatGPT |
| opencode | Yes | ChatGPT Plus or Pro sign-in |
| Amp | Yes | Your ChatGPT Plus or Pro subscription for OpenAI models |
| Reason | Yes | Sign in with ChatGPT for Plus, Pro or Business, beside Claude, Grok and Copilot plans and API keys |
From each vendor's docs, checked Nov 2, 2026. OpenAI also says it plans to wind down its contract providing OpenAI models to Cursor, with a proposed transition period of November 12, 2026.
Why Claude Code and Cursor don't take a ChatGPT plan
Claude Code is built around Claude models. Its docs list Claude subscriptions, the Claude Console, Amazon Bedrock, Google Vertex AI and Microsoft Foundry, and its gateway page says Anthropic doesn't support routing Claude Code to non-Claude models through any gateway. Community proxies that try it are unofficial.
Cursor bills OpenAI models through Cursor or your own OpenAI API key, and a ChatGPT subscription isn't an API key. OpenAI's help article points Cursor users to the Codex extension, which runs inside Cursor on your ChatGPT plan. Cursor's own API-key option works with chat models only.
Reason: all your AI subscriptions in one coding agent
Use the subscriptions you already pay for (ChatGPT Plus/Pro/Business, Claude Pro/Max, SuperGrok or X Premium+, GitHub Copilot) or your own API keys in one coding agent. Hit your limit? Reason keeps going on your other connected accounts or Reason credits.
On cost: in Reason's published benchmark on GPT-6 Astra at xhigh effort, with the same tasks and graders, Reason 1.1 scored 65.1 against Codex's 62.5 on Coding Agent Index v1.5, at 22% lower cost per solved task. That's Reason's benchmark of its own harness, with the runner published to reproduce it.
Sources (checked Nov 2, 2026)
Questions
Can I use my ChatGPT subscription in Claude Code?
No. Claude Code runs Claude models and signs in with a Claude plan, the Claude Console or a cloud provider. Anthropic doesn't support routing it to non-Claude models through a gateway.
Can I use ChatGPT Plus in Cursor?
Only through OpenAI's Codex extension, which you can install in Cursor and sign in with ChatGPT. Cursor's own agent uses Cursor's plans or an OpenAI API key, which a ChatGPT subscription doesn't include.
Does ChatGPT Plus include Codex?
Yes. Plus, at $20 a month, includes Codex on the web, in the CLI, in the IDE extension and on iOS; OpenAI describes it as enough for a few focused coding sessions each week.
Does a ChatGPT subscription include API usage?
No. OpenAI says a ChatGPT subscription doesn't include OpenAI API usage. Codex and agents with a ChatGPT sign-in run on the plan; anything that asks for an API key bills separately.
What happens in Reason when I hit my plan's limit?
Hit your limit? Reason keeps going on your other connected accounts or Reason credits. The turn moves to your other connected accounts for the same provider, then to Reason credits if your workspace can pay, and the conversation says which account it continued on.
Is Reason affiliated with OpenAI, Anthropic or GitHub?
No. Reason is built by Reason Machines and is not affiliated with or endorsed by OpenAI, Anthropic, GitHub, Anysphere or xAI. Facts about their products come from their own docs, linked under Sources.