Errors

JSON endpoints return a body with success: false, an error string and usually a detail. CSV lanes return the same information as # comment lines so a firewall importing the file does not choke on JSON.

Status	When	What to do
400	A required parameter is missing or malformed	Read error; it names the parameter
401	No key, or the key is not recognized	Send Authorization: Bearer <key>; check for a typo or a deleted key
403	The key is valid but not for this resource (for example a key without feed scope on the STIX bundle), or the request was refused as automated	Check your plan and the endpoint’s requirements
404	Unknown path or object	Check the URL against the endpoint reference
429	Daily quota or per-minute limit reached	Wait for X-RateLimit-Reset, or upgrade
5xx	Our fault	Retry with backoff; current service status is at GET /api/v1/status

An unrecognized key:

{
  "success": false,
  "error": "Invalid API key",
  "detail": "This key is not recognized. It may never have been registered, or was mistyped.",
  "register_url": "https://analytics.dugganusa.com/stix/register"
}

A CSV lane without a key answers 401 with comment lines:

# UNAUTHORIZED - API key required. Registration is free and takes about 30 seconds.
# Register free (10 queries/day, no card): https://analytics.dugganusa.com/stix/register

MCP servers answer in JSON-RPC. On Jeevesus, an invalid key returns error code -32001, and a rate limit returns HTTP 429 with error code -32029:

{ "jsonrpc": "2.0", "id": null, "error": { "code": -32029, "message": "rate_limited: minute cap 60" } }