| HTTP Code | Error Code | Meaning |
|---|---|---|
400 Bad Request | INVALID_PARAMETERS | Payload failed Zod schema validation. |
401 Unauthorized | UNAUTHENTICATED_SESSION | Missing or invalid SIWE session cookie. |
403 Forbidden | POLICY_VIOLATION | One or more of the 18 deterministic rules failed. |
404 Not Found | RESOURCE_NOT_FOUND | Requested invoice, mandate, or execution ID does not exist. |
409 Conflict | EXECUTION_IN_FLIGHT | A concurrent trade is already executing on this mandate. |
410 Gone | QUOTE_EXPIRED | Textile firm quote accept deadline has lapsed. |
Error Responses
Standardized error envelopes, HTTP status codes, and policy rejection codes.