POST `/v1/messages`

Anthropic-compatible Messages endpoint. Serves direct Anthropic and AWS Bedrock for anthropic.* model ids. Streaming and tool use are pass-through, byte-identical to upstream Anthropic.

Authentication

x-api-key: fm_live_...
anthropic-version: 2023-06-01

Request body

request json

{
  "model": "claude-3-5-sonnet-latest",
  "max_tokens": 256,
  "system": "You are concise.",
  "messages": [
    {"role": "user", "content": "What is 2+2?"}
  ]
}

Required fields

model — string. Anthropic-shape model id.
messages — array of { role: "user" | "assistant", content }.
max_tokens — integer.

Optional

system, temperature, top_p, top_k.
stream — boolean. Anthropic-style event stream.
tools, tool_choice.

MoE on the Anthropic surface

x-fm-route works here too, but Fire Mission constrains the routed decision to Anthropic-shape providers (Anthropic direct or AWS Bedrock with anthropic.* ids) so the request body stays compatible. If MoE produces a non-Anthropic-shape model, the call fails with moe_routing_unavailable.

Response (non-streaming)

response json

{
  "id": "msg_...",
  "type": "message",
  "role": "assistant",
  "model": "claude-3-5-sonnet-latest",
  "content": [{"type": "text", "text": "4"}],
  "stop_reason": "end_turn",
  "usage": {"input_tokens": 18, "output_tokens": 1}
}

Errors

Errors use the Anthropic envelope ({ type: "error", error: { type, message } }). See the errors page for Fire Mission-specific codes.

POST /v1/messages