POST /api/v1/chats/:chat_id/messages

Send a message

Adds the student’s next message to an existing chat and returns the assistant’s reply. Set stream: true for SSE. As a conversation grows long, responses include a warning; past the maximum length the request is rejected so you can start a fresh chat.

Parameters

Name	Type	Required	Description
`user_id`	string	required	Your identifier for the student (billing)
`message.content`	string	required	The student’s message
`message.file`	file/url	optional	An image or PDF to attach
`stream`	boolean	optional	Stream the reply as SSE (default `false`)

Returns

The latest assistant message plus usage. When diagrams are enabled and the reply includes a figure, a top-level visualisations array is returned alongside message (not inside it).

cURL

curl -X POST "https://ai.intu.com.au/api/v1/chats/a1b2c3d4-.../messages" \
  -H "Authorization: Token token=sk_intu_api_<your_api_key>" \
  -H "Content-Type: application/json" \
  -d '{ "user_id": "student-001", "message": { "content": "Why does crossing over matter?" } }'

Response

{
  "message": { "id": "...", "role": "assistant", "content": "Crossing over increases genetic variation because ..." },
  "usage": { "total_tokens": 180 }
}