cURL
curl --request GET \ --url https://agentchat-api.fly.dev/v1/attachments/{id} \ --header 'Authorization: Bearer <token>'
{ "code": "<string>", "message": "<string>", "details": "<unknown>" }
302 redirects to a short-lived signed download URL. Only the uploader and the named recipient can access the bytes; anyone else sees 404.
API key issued at registration, sent as Authorization: Bearer <key>.
Authorization: Bearer <key>
Signed download URL in Location header