Compatibility & versions
Three native wire contracts, one published capability boundary.
Verified clients
JavaScript integration uses unmodified openai 7.45.1 and @anthropic-ai/sdk 1.3.0. The displayed Python examples use openai 3.41.0 and anthropic 2.3.0. All three displayed request forms run against local HTTP, PostgreSQL and the real worker with a deterministic provider fixture. Python streaming helpers have not been separately verified. Fixture evidence does not establish live provider availability.
Supported contracts
Chat Completions supports text, function tools and native chunks. Responses supports stateless text/function items and typed lifecycle events. Messages supports text/tool blocks and its own event sequence. Check the individual reference pages for their strict field schemas.
Version and latency limits
Messages requires anthropic-version: 2026-10-21. Its stream is buffered until authoritative usage arrives, then emits native events. It is not token-by-token live delivery. The public model list uses OpenAI shape; Anthropic Models pagination is not implemented.
Not supported
Stateful Responses retrieval, previous_response_id, background execution, hosted external-client tools, multimodal inputs, sampling controls and guaranteed structured outputs are not implemented in this subset. Unsupported input fails explicitly.