Anthropic-compatible messages endpoint.
Authorizations
Virtual key mk-live-… on the data plane. x-api-key: mk-live-… is also accepted.
Headers
Pin this request to a routing session (sticky provider/model across a conversation). Header wins over body session_id.
256"chat-7f3a2b"
Comma-separated capability hard-filter (e.g. vision,tool_use) — candidates lacking any listed capability are excluded. Header wins over body spillway.require_capabilities. Unknown capability → 422.
"vision,tool_use"
Disambiguate a model name served by multiple providers. Must be a known provider AND on the key's allow-list (403 model_not_allowed otherwise).
"anthropic"
Opt into per-request tracing: on / 1 / true (case-insensitive). The response then carries x-spillway-trace-id.
"on"
JSON object of request tags merged into the request metadata for reporting (body metadata wins on collision). Bounded: ≤16 keys total, key ≤64 chars, value ≤256 chars.
"{\"team\":\"platform\",\"feature\":\"chat\"}"
Body
Response
Provider-shaped response (OpenAI/Anthropic JSON, or an SSE stream when streaming).