Errors & status codes

HTTP status codes

Code	Meaning	When you'll see it
200	OK	Successful request, payload in response.
201	Created	Resource created.
400	Bad Request	Invalid request body or missing required field.
401	Unauthorized	Missing or invalid credentials.
403	Forbidden	Credentials valid but not authorised for this resource (e.g. instance not visible to user).
404	Not Found	Resource (instance, document, conflict) does not exist.
409	Conflict	State-machine violation (e.g. trying to close an already-managed conflict).
422	Unprocessable Entity	Request body validates but is semantically wrong (e.g. answer length exceeds limit).
429	Too Many Requests	Rate limit hit (auth: 5 logins/min/IP).
500	Internal Server Error	Unexpected server failure. Exponential backoff retry recommended.
502	Bad Gateway	Upstream component (LLM router, vector store) unreachable.
503	Service Unavailable	Service in maintenance or degraded; respect the Retry-After header.

Error body shape

All three APIs return {"detail": "<message>"} on error. The success wrapper {"response": ...} is only present on 2xx.

{
  "detail": "Instance not found"
}

Per-API specifics

Instance API — api.kai-studio.ai

• 401 — wrong instance-id or api-key header.

• 404 — instance unknown to the platform.

Retrieval API — api-retrieval.kai-studio.ai

• 401 — token expired or revoked.

• 403 — instance access denied (group RBAC).

• 422 — query length or pagination parameter violation.

Audit API — api-audit.kai-studio.ai

• 409 — conflict already managed or ignored.

• 422 — workflow-state mismatch (e.g. answering a conflict that is in MANAGED state).

OAuth-specific errors

OAuth 2.1 endpoints return standard error responses defined in RFC 6749 §5.2:

Error code	Meaning
invalid_request	Required parameter missing, included twice, or malformed.
invalid_client	Client authentication failed (unknown client_id or bad client secret).
invalid_grant	Authorization code, refresh token, or resource-owner credential is invalid, expired, or revoked.
unauthorized_client	Client is not authorised to use the requested grant type.
unsupported_grant_type	The grant type is not supported by the authorisation server.
invalid_scope	Requested scope is invalid, unknown, malformed, or exceeds the granted scope.

See the OAuth 2.1 page for the full authentication flow.