Anthropic Claude LLM backend using the Messages API via Req.
Configuration
config :adk, :anthropic_api_key, "sk-ant-..."
# Or via environment variable
ANTHROPIC_API_KEY=sk-ant-...Usage
config :adk, :llm_backend, ADK.LLM.Anthropic
ADK.LLM.Anthropic.generate("claude-sonnet-4-20250514", %{
instruction: "You are helpful.",
messages: [%{role: :user, parts: [%{text: "Hello"}]}]
})