Runs a risk screen on one person and returns the result. Requires the Screen API to be enabled for your organization. Include interstitial.redirect_url to run the screen in interstitial mode instead: the response has status requires_action and a next_action.url to send the person to; poll GET /screens/{id} for the verdict once they finish. Send an Idempotency-Key to make retries safe: a repeated key returns the original screen with a 201, a repeated key whose screen is still running returns a 409 (retry later), a repeated key with a different external_id returns a 422, and a repeated key whose original request failed returns the same error status as that request. A request rejected before the screen is created (invalid input, 422) creates nothing, so the same key can be retried once corrected. All fields go in the JSON body; a request with a query string is rejected with a 422.