POST 404 not found HTTP status codes have a schema references to standardize the response payload returned for the error response
OpenAPI Response Post 404 Schema Ref Error
Message: POST 404 Responses MUST Use Schema Reference
Policies
Response 4xx
Client error responses are where developer experience lives or dies. Consistent 400, 401, 403, 404, and 429 responses with shared schema references make error handling predictable.