Cursor
AI code editor · Chat Completions
Cursor's OpenAI key override is the whole trick: one base URL, one key, then register the model IDs you want in chat and agent modes.
Base URL · OpenAI-compatible
https://korouter.ai/v1
Plus an API key from Keys and a bare model ID from Models. Every price on the catalog sits below the provider's official rate — pay as you go.
Setup
- 1. Open Cursor Settings → Models → API Keys.
- 2. Paste your key into OpenAI API Key, enable Override OpenAI Base URL, and set it to
https://korouter.ai/v1. - 3. Click Verify, then use Add model to register each bare model ID you want, e.g.
claude-fable-5.
Verify
Select the added model in chat and send a message. The call appears on Usage with its token breakdown and charge.
If it fails
- Verify fails with 403 (INSUFFICIENT_BALANCE) — verification sends a real request, so the account needs credits first.
- Tab autocomplete unchanged — the override covers chat and agent modes; Cursor Tab keeps using Cursor's own models.
- model not found — the custom model name must match the bare ID exactly; disable built-in models you do not route through the key.
Troubleshooting
The failures below account for nearly every unsuccessful first connection, whatever the tool.
| Status | Symptom | Fix |
|---|---|---|
| 401 | Key missing, mistyped, or deleted | Re-copy the key from Keys and confirm which header your tool sends — Authorization: Bearer or x-api-key. |
| 403 | No credits on the account (INSUFFICIENT_BALANCE) | Add credits first. Verify buttons and test prompts inside tools fire real requests. |
| 404 | Model not found | Send the bare model ID exactly as listed on Models — no provider/ prefix in the request body. |
| 429 | Concurrency or key spend limit reached | Lower parallel requests, or raise the key's spend limit, then retry with backoff. |
The full status-code table, retry guidance, and error envelopes are in Errors & limits. Still stuck? Email support@korouter.ai with the tool name, the model ID, and the exact error text.
Other tools
Free to sign up, no monthly fee — pay as you go with credits.