Audits the JSON-LD structured data on one public web page: P1 for no schema or missing required properties, P2 for a low rich-result score, each with the properties to add. Call it when a page is missing rich results in Google or before publishing a page that should earn them. Input: url. Returns in seconds. Errors: 400 invalid input, 502 audit failed, 504 timed out. You are not charged for an error response.