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Cursor IDE Integration with LiteLLM

This tutorial shows you how to integrate Cursor IDE with LiteLLM Proxy, allowing you to use any LiteLLM-supported model through Cursor's interface with BYOK (Bring Your Own Key) and custom base URL.

Benefits of using Cursor with LiteLLM​

When you use Cursor IDE with LiteLLM you get the following benefits:

Developer Benefits:

  • Universal Model Access: Use any LiteLLM supported model (Anthropic, OpenAI, Vertex AI, Bedrock, etc.) through the Cursor IDE interface.
  • Higher Rate Limits & Reliability: Load balance across multiple models and providers to avoid hitting individual provider limits, with fallbacks to ensure you get responses even if one provider fails.
  • Streaming Support: Full streaming support with proper response transformation for Cursor's expected format.

Proxy Admin Benefits:

  • Centralized Management: Control access to all models through a single LiteLLM proxy instance without giving your developers API Keys to each provider.
  • Budget Controls: Set spending limits and track costs across all Cursor usage.
  • Request Logging: Track all requests made through Cursor for debugging and monitoring.

Prerequisites​

Before you begin, ensure you have:

  • Cursor IDE installed
  • A running LiteLLM Proxy instance with HTTPS enabled (HTTP is not supported)
  • A valid LiteLLM Proxy API key
  • An HTTPS domain for your LiteLLM Proxy (required by Cursor)

Quick Start Guide​

Step 1: Install LiteLLM​

Install LiteLLM with proxy support:

pip install litellm[proxy]

Step 2: Configure LiteLLM Proxy​

Create a config.yaml file with your model configurations:

config.yaml
model_list:
  - model_name: gpt-4o
    litellm_params:
      model: gpt-4o
      api_key: os.environ/OPENAI_API_KEY
  
  - model_name: claude-3-5-sonnet
    litellm_params:
      model: anthropic/claude-3-5-sonnet-20241022
      api_key: os.environ/ANTHROPIC_API_KEY

general_settings:
  master_key: sk-1234567890 # Change this to a secure key

Step 3: Start LiteLLM Proxy​

Start the proxy server with HTTPS enabled:

litellm --config config.yaml --port 4000
HTTPS Required

Important: Cursor IDE requires HTTPS connections. HTTP (http://) will not work. You must:

  • Deploy your LiteLLM Proxy with HTTPS enabled
  • Use a valid SSL certificate
  • Access the proxy via an HTTPS domain (e.g., https://your-proxy-domain.com)

For local development, you'll need to set up HTTPS (e.g., using a reverse proxy like nginx with SSL, or deploying to a cloud service with HTTPS).

Step 4: Configure Cursor IDE​

Configure Cursor IDE to use your LiteLLM proxy with the /cursor/chat/completions endpoint:

  1. Open Cursor IDE
  2. Go to Settings → Features → AI
  3. Enable "Use Custom API" or "Bring Your Own Key"
  4. Set the following:
    • Base URL: https://your-proxy-domain.com/cursor (⚠️ Important: Must use HTTPS and include /cursor)
    • API Key: Your LiteLLM Proxy API key (e.g., sk-1234567890)
HTTPS Required

Cursor IDE requires HTTPS connections. HTTP (http://) will not work. You must:

  • Use an HTTPS URL for your base URL (e.g., https://your-proxy-domain.com/cursor)
  • Ensure your LiteLLM Proxy is accessible via HTTPS
  • Have a valid SSL certificate configured

Example Configuration:

Base URL: https://your-proxy-domain.com/cursor
API Key: sk-1234567890

Replace your-proxy-domain.com with your actual HTTPS domain where LiteLLM Proxy is running.

Why /cursor in the base URL?

Cursor automatically appends /chat/completions to the base URL you provide. By setting the base URL to https://your-proxy-domain.com/cursor, Cursor will send requests to /cursor/chat/completions, which is the special endpoint that handles Cursor's Responses API input format and transforms it to Chat Completions output format.

If you set the base URL to just https://your-proxy-domain.com, Cursor would send requests to /chat/completions, which won't work correctly with Cursor's request format.

Step 5: Test the Integration​

  1. Restart Cursor IDE to apply the settings
  2. Open a code file and try using Cursor's AI features (completions, chat, etc.)
  3. Your requests will now be routed through LiteLLM Proxy

You can verify it's working by:

  • Checking the LiteLLM Proxy logs for incoming requests
  • Using Cursor's chat feature and seeing responses stream correctly
  • Checking your LiteLLM dashboard for request logs and cost tracking

How It Works​

The /cursor/chat/completions endpoint is specifically designed to handle Cursor's unique request format:

  1. Input: Cursor sends requests in OpenAI Responses API format (with input field)
  2. Processing: LiteLLM processes the request through its internal /responses flow
  3. Output: The response is transformed to OpenAI Chat Completions format (with choices field) that Cursor expects

This transformation happens automatically for both streaming and non-streaming responses.

Advanced Configuration​

Using Different Models​

You can configure Cursor to use different models by updating your config.yaml:

config.yaml
model_list:
  - model_name: gpt-4o
    litellm_params:
      model: gpt-4o
      api_key: os.environ/OPENAI_API_KEY
  
  - model_name: claude-3-5-sonnet
    litellm_params:
      model: anthropic/claude-3-5-sonnet-20241022
      api_key: os.environ/ANTHROPIC_API_KEY
  
  - model_name: gemini-pro
    litellm_params:
      model: gemini/gemini-1.5-pro
      api_key: os.environ/GEMINI_API_KEY

Then in Cursor, you can specify which model to use in your requests.

Rate Limiting and Budgets​

Set up rate limits and budgets in your config.yaml:

config.yaml
general_settings:
  master_key: sk-1234567890

litellm_settings:
  # Set max budget per user
  max_budget: 100.0
  
  # Set rate limits
  rate_limit: 100  # requests per minute

Request Logging​

All requests from Cursor will be logged by LiteLLM Proxy. You can:

  • View logs in the LiteLLM Admin UI
  • Export logs to your preferred logging service
  • Track costs per user/team

Troubleshooting​

Cursor shows no output​

  • Check base URL: Ensure it uses HTTPS and includes /cursor (e.g., https://your-proxy-domain.com/cursor, not http:// or without /cursor)
  • Verify HTTPS: Cursor requires HTTPS - HTTP connections will not work
  • Check API key: Verify your LiteLLM Proxy API key is correct
  • Check proxy logs: Look for errors in the LiteLLM Proxy logs

Requests failing​

  • Verify HTTPS is enabled: Cursor requires HTTPS connections. Ensure your LiteLLM Proxy is accessible via HTTPS with a valid SSL certificate
  • Verify proxy is running: Check that LiteLLM Proxy is accessible at your HTTPS base URL
  • Check SSL certificate: Ensure your SSL certificate is valid and not expired
  • Check model configuration: Ensure the model you're trying to use is configured in config.yaml
  • Check API keys: Verify provider API keys are set correctly in environment variables

HTTP not working​

If you're trying to use HTTP (http://) and it's not working:

  • This is expected: Cursor IDE requires HTTPS connections
  • Solution: Deploy your LiteLLM Proxy with HTTPS enabled (use a reverse proxy like nginx, or deploy to a cloud service that provides HTTPS)

Streaming not working​

The /cursor/chat/completions endpoint automatically handles streaming. If streaming isn't working:

  • Check that your model supports streaming
  • Verify the proxy logs for any transformation errors
  • Ensure Cursor IDE is up to date