OpusGate

Cursor

Cursor lets you override the OpenAI base URL, so its chat can talk to OpusGate's OpenAI-compatible side. Configuration lives inside Cursor's own settings UI (there is no config file to script — set it up once by hand).

Required values
Base URL: https://api.opusgate.dev/v1 — keep the /v1, Cursor appends /chat/completions itself.
API key: your sk-og-... from the Keys page.

Setup

  1. Open Settings (Cmd/Ctrl + ,) → Models in the left sidebar.
  2. Click + Add Model and type the exact model ID you want (e.g. claude-opus-4.8, claude-sonnet-4.6). IDs are case-sensitive — copy them from the models page.
  3. Turn on Override OpenAI Base URL and enter https://api.opusgate.dev/v1.
  4. In the OpenAI API Key field, paste your sk-og-... key. (Despite the "OpenAI" label, the key goes to OpusGate.)
  5. Click Verify — Cursor sends a test request through OpusGate. A green check means you're done.

What routes through OpusGate — and what doesn't

  • Only the Chat / Plan panel (Cmd/Ctrl + L) uses the custom endpoint. This is a deliberate Cursor limitation, not an OpusGate one.
  • Agent, Edit/Composer, Apply and autocomplete stay on Cursor's backend and keep billing to your Cursor subscription.
  • Want full agentic coding at OpusGate prices? Use Claude Code, Cline or Roo Code — they route everything through your key.

Troubleshooting

Verify fails

Three usual causes: the base URL is missing /v1; the key was pasted with a space or is revoked (issue a fresh one); or your balance is empty (top up — verification makes a real, tiny billed request).

Model responds with "model not found"

The model name you added must match an OpusGate ID exactly — claude-opus-4.8, not claude-3-opus or a display name. Check the catalog.

Custom model works, then Cursor switches back

Cursor re-enables its built-in models after some updates. Re-select your custom model in the picker at the bottom of the chat panel.

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