Gemini

The gemini provider speaks the native Gemini API (generateContent). Use it for Gemini models on Google's own endpoint, or for any proxy that serves the same API shape.

model:
  provider: gemini
  id: gemini-3.6-flash

With no base_url, requests go to https://generativelanguage.googleapis.com and the key is read from GEMINI_API_KEY — get one from Google AI Studio. Point api_key_env at a different env var if your key lives elsewhere; the mechanics are in Providers.

model:
  provider: gemini
  id: gemini-3.6-flash
  base_url: https://my-gemini-proxy.internal   # any generateContent-compatible endpoint
  api_key_env: PROXY_API_KEY

Gemini is also reachable through Google's OpenAI-compatible endpoint with the openai-compatible dialect (base_url: https://generativelanguage.googleapis.com/v1beta/openai/). Prefer the native dialect: it reports thinking-token usage correctly and doesn't depend on the compatibility layer's dialect mapping.

Two behaviors worth knowing:

• Tool-call ids are synthesized. Gemini matches tool results to calls by function name rather than id, and not every model version emits ids at all, so the provider mints ids of the form <name>#<n> and recovers the name when replaying tool results. This is invisible in normal operation; it only matters if you read raw session transcripts.
• Thinking tokens count as output. Reasoning models like Gemini 3.6 Flash report thought tokens separately (thoughtsTokenCount); they are billed as output, so the provider adds them to the run's output-token usage.

For reaching Gemini models on Vertex AI (service-account auth rather than API keys), put a rewriting proxy such as LiteLLM behind base_url — the framework deliberately holds no cloud-SDK credentials.