openai, anthropic, mistralai, google-genai), the MCP client, tiktoken, httpx and boto3; they are imported on first use, so a process that talks to one provider never loads the others.
Extras
Optional packages
Some tools and stores need a package the extras do not cover. Each one tells you what to install when it is missing.API keys
Each provider and service reads its key from the environment:
Every client also accepts
api_key= directly. A .env file read with python-dotenv (dotenv.load_dotenv()) is the pattern the examples use.