Anthropic, OpenAI, Google Gemini, xAI, OpenRouter, Mistral, Groq, Cohere and Together AI are supported, plus any OpenAI-compatible endpoint. Each agent is assigned a model, so a sales development rep can run on an inexpensive model while an architect runs on a larger one.
Changing an agent's model does not change anything else about it. Usage is billed by the provider, on your key.