Using Cursor

Compatibility: works with caveats. Cursor can send its local Chat and Agent requests to luv13 through the OpenAI API key setting with Override OpenAI Base URL turned on. Tab, Auto, Cloud or Background Agents, Automations, the Cursor CLI and Cursor's API and SDK can't use your own key. The override applies to every OpenAI-family request while it's on. Cursor staff have also said Cursor sometimes sends Responses API requests, which luv13 doesn't serve.

Before you start

You need:

• The Cursor desktop app.
• A luv13 API key. The Quickstart shows how to get one.
• The model id luv13/glm-5.3-flash, from the live list at https://api.luv13.ai/v1/models. See GLM-5.3 Flash for details on the model.

Facts about luv13 that affect this setup:

• luv13 serves one generation endpoint, POST /v1/chat/completions, plus GET /v1/models. /v1/responses, /v1/messages, /v1/completions and /v1/embeddings return 404 (checked 2026-09-30). See Endpoints.
• Every model costs a flat $0.33 per 1M tokens, input the same as output. See Pricing.
• The model list at https://api.luv13.ai/v1/models doesn't report context length, so luv13 publishes no per-model limits. See the model list.

Test your key and model first

Run these two checks in a terminal before you touch the tool. They take a few seconds and rule out key and model problems.

1. The model id exists. This call needs no key:

curl -s https://api.luv13.ai/v1/models

The list should include "id":"luv13/glm-5.3-flash".

2. Your key works for chat. Set the key in your shell first (export LUV13_API_KEY="your luv13 key"), then run:

curl -s https://api.luv13.ai/v1/chat/completions \
  -H "Authorization: Bearer $LUV13_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "luv13/glm-5.3-flash",
    "messages": [{"role": "user", "content": "Reply with the word ready."}],
    "max_tokens": 20
  }'

With a valid key you should get back a JSON chat completion whose choices[0].message.content holds the reply, plus a usage block. If you see {"error":{"code":401,"message":"unauthorized","type":"invalid_auth"}} instead, the key is missing or wrong, and no tool setting will fix that.

Set up Cursor

These steps follow Cursor's "Bring your own API key" help page, OpenAI's help article on using OpenAI models in Cursor, and replies from Cursor staff on the Cursor forum, all read on 2026-09-30. Cursor's own docs don't document the base URL override step by step, so the labels in steps 4 and 5 may look a little different in your version.

1. Open Cursor Settings (the gear icon, or the command palette) and select Models.
2. Find the OpenAI API Key field.
3. Paste your luv13 key into it. Don't paste it anywhere else, such as a rules file or chat.
4. Turn on Override OpenAI Base URL and enter exactly:

   https://api.luv13.ai/v1

Use no trailing slash and no /chat/completions. Cursor adds the path itself.

5. Save or verify the key.
6. Add a custom model with the name:

   luv13/glm-5.3-flash

The name must match luv13's id exactly, including the luv13/ prefix.

7. Make sure the new model is enabled, then pick it in the model picker of a local Chat or Agent session.
8. Send a short prompt such as "Reply with the word ready."

What works and what doesn't

Things to know

• Requests go through Cursor's servers. Cursor's docs say your key isn't stored on its servers, but it's sent to Cursor's backend with every request, because Cursor builds the final prompt there. So luv13 gets the call from Cursor, not from your computer.
• Privacy. Cursor's docs say its Zero Data Retention policy doesn't apply when you use your own key. How luv13 handles data is covered on Data and Privacy.
• Billing. luv13 bills you for the tokens at its flat rate. On Cursor's Teams and Enterprise plans, Cursor's docs say its own per-token "Cursor Token Rate" still applies to requests made with your key. Check Cursor's pricing for your plan.
• The override is global. Cursor staff have confirmed that while Override OpenAI Base URL is on, all OpenAI-family requests go to the custom URL, even for models picked from Cursor's built-in list. The only workaround they give is to turn the override off when you use Cursor's models and back on for luv13.

Common errors

General tip: if a request fails and you're not sure whether the problem is Cursor or luv13, run test 2 above with the same key and model. If curl works, the problem is in the Cursor settings.

Sources

• Cursor, "Bring your own API key" (read 2026-09-30)
• OpenAI Help Center, "Using OpenAI models in Cursor" (marked "Updated: last month", read 2026-09-30)
• Cursor forum, staff replies on the base URL override (August and September 2026) and Cursor forum, "The custom override of the OpenAI base URL is unusable" (February 2026)
• luv13 endpoints and errors checked live with curl on 2026-09-30.

Related: Base URL, OpenAI-Compatible APIs, Errors and Status Codes.