Lookup Harbor Action

Look up exactly one record using a granted read-only Harbor action. Use a scoped credential belonging to this Harbor, including a read-only credential. An administrator must grant the Connection, read-only operation, lookup field, and returned fields. Select an identity with [List actions](../../../../../api-reference/harbors/actions/list), then inspect its effective lookup and output fields with [Describe action](../../../../../api-reference/harbors/actions/describe). Polytomic checks current grants and provider capabilities on each lookup. The response contains one record under `data`, limited to the selected fields. Omitting `fields` returns all currently available granted outputs; new provider fields remain excluded until an administrator grants them. Salesforce uses `Id`; HubSpot uses `hs_object_id`. Preserve these IDs as strings. Alternate keys, fuzzy matches, search, and batching are unsupported. A definite absence returns `404 Not Found`. More than one exact match returns `409 Conflict`. Invalid selections return `400 Bad Request`; unavailable capabilities or provider failures return `503 Service Unavailable`. Errors do not include lookup values or provider response bodies. This request is synchronous and read-only. It requires no preparation, approval, execution identifier, or status polling. It creates no write receipt or private write evidence. Harbor Activity records `action.looked_up` with field names and an outcome, never the lookup value or returned values. If Activity cannot be recorded, Polytomic returns no record. Unknown properties, duplicate keys, invalid Unicode, trailing JSON, and bodies larger than 256 KiB are rejected. Lookup values must be JSON scalars. Numeric values must use integer notation within +/-9007199254740991. Send a new nonzero UUID in `X-Polytomic-Activity-Request-ID` for each request. `X-Polytomic-Harbor-Session` is optional for direct REST requests. A supplied session must be active and bound to your credential and Harbor.