Create message (Anthropic)

Sends a structured list of input messages and generates the next message in the conversation. This is the Anthropic Messages API. Reasoning behavior mirrors the Chat Completions API: corti-s1 and corti-s1-mini generate chain-of-thought reasoning, while -instant variants do not. However, the Anthropic Messages API response does not expose reasoning as a separate field — content is returned as text blocks only.

POST /messages

cURL

Basic

curl --request POST \
  --url https://ai.eu.corti.app/anthropic/v1/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'anthropic-version: <anthropic-version>' \
  --data '
{
  "model": "corti-s1",
  "max_tokens": 500,
  "messages": [
    {
      "role": "user",
      "content": "Count from 1 to 5"
    }
  ]
}
'

200

{
  "id": "<string>",
  "type": "message",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "<string>"
    }
  ],
  "model": "<string>",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 123,
    "output_tokens": 123,
    "cache_creation_input_tokens": 123,
    "cache_read_input_tokens": 123
  }
}

{
  "error": "<string>",
  "detail": "<string>"
}

{
  "error": "<string>",
  "detail": "<string>"
}

Authorizations

Authorization · string · header · required

Use a Corti-issued bearer token.

Headers

anthropic-version · string · default: 2023-06-01 · required

Anthropic API version header.

Body

application/json

model · enum<string> · default: corti-s1 · required

Available options: corti-s1, corti-s1-instant, corti-s1-mini, corti-s1-mini-instant

max_tokens · integer · required

Maximum tokens to generate. Required by the Anthropic API.

Required range: x >= 1

messages · object[] · required

Conversation messages. Supported roles: user, assistant.

Minimum array length: 1

Show child attributes

system · string | null

System prompt. Equivalent to a system message in chat completions.

stream · boolean · default: false

If true, returns SSE with typed events: message_start, content_block_start, content_block_delta, content_block_stop, message_delta, message_stop.

temperature · number<float> · default: 1

Required range: 0 <= x <= 1

top_p · number<float> · default: 0.95

Response

200

application/json

Successful response. For non-streaming requests, returns a complete message object. For streaming requests, returns Server-Sent Events (SSE) with typed events: message_start, content_block_start, content_block_delta, content_block_stop, message_delta, message_stop.

id · string

Unique message ID (e.g. chatcmpl-3e537413-...).

type · enum<string>

Available options: message

role · enum<string>

Available options: assistant

content · object[]

Array of content blocks.

Show child attributes

model · string

The model name used for this response.

stop_reason · enum<string>

Why generation stopped.

Available options: end_turn

usage · object

Show child attributes