Use Claude Code, Codex and Cursor's models from one place
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.
Connect the plans you already pay for
In Settings › Models, connect subscriptions such as Claude (Pro or Max), ChatGPT (Plus, Pro or Business), Grok (SuperGrok or X Premium+) or GitHub Copilot, or add API keys. Reason runs on your own accounts first; a Reason plan's credits cover the rest.
Give it a task you know the answer to
In the composer, name the repository and paste a task you've already solved, such as a failing test. Reason works on its own cloud computer, runs the tests and opens a pull request, so you can compare its diff with your other agent's.
Switch the model and compare
Start a second Session on the same branch with a model from another provider, and ask it to review the first diff. Each Session shows the model and account it ran on.
Claude Code, Codex and Cursor at a glance
| Claude Code | Codex | Cursor | |
|---|---|---|---|
| Made by | Anthropic | OpenAI | Anysphere |
| Kind | Coding agent | Coding agent | AI code editor and agent |
| Open source | No | CLI under Apache-2.0 | No |
| Models | Claude | OpenAI; open models with --oss | Grok models included; others at API list price |
| Cloud tasks | Cloud sessions | Codex cloud | Cloud Agents, Premium and higher |
| Schedules | Scheduled tasks (research preview) | Scheduled tasks | Not listed in the docs we read; Bugbot reviews every pull request update |
| Slack | @Claude | From ChatGPT Plus | @cursor |
| Entry plan | Pro, $20 a month | ChatGPT Free and Go include it; Plus $20 | Free; Plus $8 |
| Coding Agent Index v2.0 | 62 (Opus 5.5) | 55 (GPT-6 Astra) | No entry found |
From each vendor's own pages and Artificial Analysis's comparison pages, checked Nov 2, 2026.
Does the tool matter if the model is the same?
Yes. A harness decides how the model reads code, runs tools and spends tokens. In Reason's published runs on the same model (GPT-6 Astra at xhigh), same tasks and same graders, Reason 1.1 scored 65.1 against Codex's 62.5 on the earlier 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.
Reason is an always-on teammate that is also a frontier coding agent: its own cloud computer per Session, memory across Sessions, Loops and Slack, and the model picked per task from Reason's models or the Claude, ChatGPT, Grok and Copilot plans you connect. Hit your limit? Reason keeps going on your other connected accounts or Reason credits. It isn't open source and has no free plan.
Sources (checked Nov 2, 2026)
- Anthropic: Claude plans and pricing
- Claude Code docs: Claude Code on the web
- Claude Code docs: scheduled tasks
- Claude Code docs: Claude Code in Slack
- OpenAI: Codex pricing
- OpenAI: Codex cloud
- openai/codex on GitHub (Apache-2.0)
- Cursor: pricing
- Cursor docs: Cloud Agents
- Artificial Analysis: Coding Agent Index
- Artificial Analysis: Claude Code vs Codex
- Reason: Reason 1.1 Coding Agent Index results (Oct 10, 2026)
- Reason benchmark repository and methodology
Questions
Which is the best AI coding tool in 2026: Claude Code, Codex or Cursor?
On Artificial Analysis's Coding Agent Index v2.0, Claude Code on Opus 5.5 leads Codex on GPT-6 Astra, 62 to 55, and we found no Cursor entry. Cursor is the editor of the three. Try your own task in each.
Which runs in the cloud?
All three can: Claude Code cloud sessions, Codex cloud tasks and Cursor Cloud Agents keep working with your laptop closed, on the plans that include them.
Which is cheapest?
Codex is included in ChatGPT Free and Go; Cursor has a free plan and Plus at $8 a month; Claude Code starts at $20 a month with Claude Pro.
Can I use more than one?
Yes. Many people keep two, and Reason can run Claude and OpenAI models on the Claude and ChatGPT plans you connect, so a task continues when one runs out.
What happens when an agent hits its usage limit?
Claude Code, Codex and Cursor stop or offer paid usage at their plan's limits. Hit your limit? Reason keeps going on your other connected accounts or Reason credits.
Is Reason affiliated with these vendors?
No. Reason is built by Reason Machines and is not affiliated with or endorsed by Anthropic, OpenAI, Anysphere, Cognition, GitHub, Google or xAI. Facts about their products come from their own pages, linked under Sources.