Race
Send one prompt to two, three or four models at once, watch them work side by side, and keep the result you like.
Different models are good at different things, and often the quickest way to learn which one handles a task well is to try them. A race sends the same prompt to several models at once. Each works in its own session, and you keep the one that did best.
Race is in preview. Races run in the desktop app and are remembered on the computer that started them. Judging, merging a winner's changes for you, and cost comparison before you start are coming soon.
Start a race
- In the composer, open the Race menu (the trophy icon, "Race the prompt across models").
- Choose Race ×2, ×3 or ×4. The menu shows which models will race. Cusp picks lanes from different providers first, so a race compares genuinely different models.
- Write the prompt and send it.
Cusp starts one session per lane with the same prompt and opens the race view. Choose Off in the same menu to go back to a single session.
Lanes and worktrees
In a git repository, every lane runs in its own worktree on a branch named cusp/race-<id>-<n>. Lanes can edit and run commands without touching your working copy or each other. Outside a git repository, lanes share the folder, so prefer read-only prompts (questions, plans, reviews) there.
Each lane is an ordinary session. It asks for permission like any other session, appears in the sidebar and the inbox, and has its own receipt.
Watch the race
The race view shows one column per lane with its model, its status and its live transcript.
| Status | Meaning |
|---|---|
| Queued | The lane hasn't started yet |
| Running | The model is working |
| Waiting for you | The lane needs a permission or an answer |
| Done | The lane finished |
| Failed | The lane stopped with an error |
| Stopped | You stopped the lane |
When lanes finish, Cusp marks the notable ones, for example Fastest and Cheapest.
Use ← and → to move between lanes and Enter to pick one.
Pick a winner
Choose Use this on the lane you want to keep. Cusp archives the other lanes and opens the winner as a normal session, so you can keep working in it.
Picking a winner doesn't merge anything. The winner's changes stay on its branch. Review them in the Changes pane, then merge the branch the way you normally would, or ask the agent in that session to do it.
Forget race removes the race grouping. The lane sessions themselves stay in the sidebar until you archive or delete them.
Limits
- A race is remembered on the computer that started it. Opening the race link elsewhere shows "This race isn't on this computer". The lane sessions are still available as ordinary sessions.
- Each lane costs what a session on that model costs. A ×4 race costs roughly four sessions.
- There's no judge yet. You compare the lanes yourself.
Next
- Review: look closely at the winning diff.
- Budgets and receipts: see what each lane cost.