curl -X POST 'https://api.gumloop.com/api/v1/sessions/sess_xYz789AbCd/messages' \
  -H 'Authorization: Bearer YOUR_ACCESS_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{"input": "Now write a follow-up email."}'

{
  "session": {
    "id": "sess_xYz789AbCd",
    "agent_id": "abc123DEFghiJKL",
    "messages": [
      {
        "id": "msg_a1b2c3",
        "role": "user",
        "content": "Research Acme Corp and draft a brief.",
        "created_at": "2026-05-15T14:32:00Z",
        "creator_id": "user_2b9d71f0",
        "parts": null
      },
      {
        "id": "msg_d4e5f6",
        "role": "assistant",
        "content": "Here is what I found about Acme Corp...",
        "created_at": "2026-05-15T14:32:09Z",
        "creator_id": null,
        "parts": null
      },
      {
        "id": "msg_g7h8i9",
        "role": "user",
        "content": "Now write a follow-up email.",
        "created_at": "2026-05-15T14:35:00Z",
        "creator_id": "user_2b9d71f0",
        "parts": null
      }
    ],
    "created_at": "2026-05-15T14:32:00Z",
    "state": "processing",
    "agent_name": "Sales research agent",
    "agent_team_id": "team_4f8c92ab",
    "agent_creator_user_id": "user_2b9d71f0",
    "agent_icon_url": null,
    "agent_tools": [],
    "participants": {
      "user_2b9d71f0": {
        "first_name": "Ada",
        "last_name": "Lovelace"
      }
    },
    "creator": {
      "id": "user_2b9d71f0",
      "first_name": "Ada",
      "last_name": "Lovelace",
      "email": "ada@example.com",
      "profile_picture": null
    }
  },
  "queue_position": null
}