The Buyer object includes contact and company information, ICP and Persona evaluation, Target Lists, Signal counts, attribution, and first and last Signal details.signal_count uses the same Signal type naming as the Signals API:
An API key can only retrieve Buyers belonging to its associated workspace.If the Buyer does not exist or belongs to another workspace, the API returns:
404 Not Found
The API does not reveal whether a Buyer exists in another workspace.