Describe one granted operation and its currently available enabled fields.

Select an identity from List actions. Supply its connection_id, schema_id, and operation_id. Use a scoped credential belonging to this Harbor; description does not require write access.

effect identifies an operation as read_only or mutating. For read-only operations, lookup_fields and output_fields contain only fields both granted by the administrator and currently available through the Connection. input_fields is empty. Use Lookup action to return one projected record without preparation.

For mutations, input_fields contains only granted, currently available fields. lookup_fields and output_fields describe the connector's lookup and output. Fields retain their types, constraints, required flags, and nullability. Supply exactly one lookup when lookup_fields is nonempty; otherwise omit it. Omitted input fields remain unchanged. Explicit null requires nullable: true.

For mutations, idempotency describes remote deduplication, not permission to retry. Harbor write receipts remain metadata-only.

A provider discovery failure or a granted operation that is no longer available returns 503 Service Unavailable, not an empty field list. An ungranted identity returns 403 Forbidden. These responses do not revoke saved permissions. Polytomic checks current grants and provider capabilities again at execution.

Description fetches only the selected object's operations. It does not fetch fields for the entire catalog. Lookup permissions are checked against fresh provider metadata. Provider permissions and automation still apply.

Send a new nonzero UUID in X-Polytomic-Activity-Request-ID. A supplied X-Polytomic-Harbor-Session must be active and bound to this credential and Harbor. Successful description is recorded as action.listed.