Providers

Sandgrouse automatically detects which LLM provider a request is intended for by inspecting the request headers. No configuration is needed — just point your tool at the proxy and sandgrouse handles routing.

Supported providers

Detection is evaluated in the order listed above. If a request contains both x-goog-api-key and Authorization: Bearer, it is routed as a Gemini request.

Anthropic (Claude Code)

Set the base URL before launching Claude Code:

export ANTHROPIC_BASE_URL=http://localhost:8080

Claude Code sends the anthropic-version and x-api-key headers on every request. Sandgrouse detects these and forwards to https://api.anthropic.com.

OpenAI (Cursor, GitHub Copilot)

export OPENAI_BASE_URL=http://localhost:8080

Any request with an Authorization: Bearer header that doesn't match another provider is routed to https://api.openai.com. This covers Cursor, GitHub Copilot, and any tool using the OpenAI SDK.

Google Gemini

export GEMINI_BASE_URL=http://localhost:8080

Requests with the x-goog-api-key header are routed to https://generativelanguage.googleapis.com.

Unknown providers

If sandgrouse cannot detect the provider from the request headers, it returns a 400 Bad Request with a message listing the expected headers. This prevents silent routing failures.

How routing works

When a request arrives at localhost:8080/v1/messages, sandgrouse:

1. Inspects the request headers to identify the provider
2. Rewrites the URL to the provider's upstream (e.g., https://api.anthropic.com/v1/messages)
3. Forwards all headers and the request body transparently
4. Returns the upstream response to the client

Your API keys are passed through as-is. Sandgrouse never stores, logs, or modifies authentication credentials.