Cost-efficient autonomous coding agent that writes code, runs tests and opens pull requests — in the cloud, locally, or from terminal, web or Slack.
Homepage hero — Reason is the world's best coding agent
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What is Reason?
A state-of-the-art coding agent for cost efficiency
Reason is an autonomous coding agent built for cost efficiency. Give it a task and it writes code, runs tests and opens a pull request — scoring higher than harnesses like Codex and Pi on benchmarks such as Terminal Bench 4.0 and DeepSWE while being 22% cheaper. It connects to a GitHub repo and assigns issues, producing evidence-backed pull requests complete with screen recordings, logs and before/after screenshots. Sessions run detached from the machine they drive: they survive crashes, can be rewound, and hop between cloud Linux, cloud Mac and your own Mac without losing state. You can drive Reason from the terminal, the Mac app, the web app or Slack, with your choice of models and your existing coding-plan subscriptions plugged in (with automatic rollover at rate limits). It can even import and resume sessions from Claude Code, Codex, OpenCode or Devin. Start free on your own computer; cloud runs are billed by credits.
Platforms and languages
Reason Availability
Platforms
Languages
Capabilities
Reason Key Features
Autonomous coding agent for GitHub
Connect a repo, assign an issue, and Reason writes code, runs tests and opens an evidence-backed pull request with screen recordings, logs and before/after screenshots.
Runs in the cloud or locally
The agent harness runs detached from the machine it drives, so sessions survive crashes, can be rewound, and hop between cloud Linux, cloud Mac and your own Mac.
Cost-efficient harness
A small toolset and short append-only prompts keep every turn fully cache-eligible — scoring 65.1 vs Codex's 62.5 on the Coding Agent Index at 22% lower cost per solved task.
Multi-surface access
Drive it from the terminal, Mac app, web app or Slack with your choice of models, and plug in your existing coding-plan subscriptions with automatic rollover when one hits rate limits.
Session portability
Import and resume an existing Claude Code, Codex, OpenCode or Devin session and keep going.
Best for
Who uses Reason?
Software developers and engineering teams
ship code faster with a cost-efficient coding agent across GitHub, terminal, Slack and the web
Plans and access
Reason Pricing
Freemium
Start free on your own computer; cloud runs billed by credits. No public price list.
Common questions
Reason FAQs
Is Reason free?
You can start free on your own computer. Cloud runs are billed by credits; there is no published price list, and YC startups reportedly get $1,000 in credits.
Where can I run Reason?
In the terminal, the Mac app, the web app, or Slack. Sessions run in the cloud or locally and can hop between cloud Linux, cloud Mac and your own Mac.
Which models does Reason use?
Your choice of models, including your existing coding-plan subscriptions with automatic rollover when one hits its rate limit.
Can Reason continue a session from another agent?
Yes — it can import and resume existing Claude Code, Codex, OpenCode or Devin sessions.
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