Choose your harness
A "harness" is just the app that runs your agent on your computer. You have two good options: Codex and Claude Code. You only need one. This page helps you pick.
The short version: we recommend Codex. It's the smoother, more polished product to live in day to day. Its model isn't the strongest one out there, but the experience is the nicest. Pick Claude Code if you want the strongest frontier models, like Opus, doing your thinking.
Just tell me which one
- Want the easiest, nicest ride? Codex. It's our default pick.
- Want the most capable models, like Opus, for hard thinking? Claude Code.
- On Linux? Claude Code. It's the only one with a Linux option.
Codex
Recommended default
- The smoother, more polished app to use every day
- Desktop app for Mac and Windows, no terminal
- No Linux app
- Runs on a ChatGPT subscription
- Its model isn't the strongest around
Claude Code
For the best frontier models
- A capable, straightforward app to use every day
- Desktop app for Mac and Windows, no terminal
- The only option on Linux (via the command line)
- Runs on a Claude subscription
- Access to the strongest models, like Opus, for hard thinking and writing
What runs where
- Mac: Codex or Claude Code, both as a desktop app.
- Windows: Codex or Claude Code, both as a desktop app.
- Linux: Claude Code only, via the command line.
One thing worth knowing up front: whichever you pick, the agent runs on your computer and your files stay on your computer. The harness is just the doorway.
Can't decide? Go with Codex. You can always switch later. The workspace files are identical for both, so nothing you build is locked to one harness.
Stuck or need help?
Send a message and it comes straight to me. Tell me where you got stuck and I'll write back.
Rather have it done for you?
If following the steps yourself isn't how your brain works today, that's fine. On a Zoom call you share your screen and hand me control, and I set it up for you, right there on your own computer. You watch it come together and end the call with a working setup, nothing left on your plate.
Pick a time below. No pitch, no pressure, no homework beforehand.