Sending canned responses via Conversations API for chat

Attempting to send a canned response during an active chat session using the Conversations API. The documentation suggests a specific payload structure, but I am receiving a 400 Bad Request error. My current POST request to /api/v2/conversations/chat/{id}/messages includes the canned response ID, yet the system rejects it. Is there a specific format required for the text content when referencing a canned response ID in the request body?