{"ok":true,"count":2,"http_webhook_count":0,"buyers":[{"buyer_agent_id":"capital-desk-smoke","mode":"stub_autobuy","webhook_url":null,"note":"Legacy smoke peer — notify only (stub autobuy OFF; real x402 path)","created_at":null},{"buyer_agent_id":"capital-desk-http","mode":"stub_autobuy","webhook_url":null,"note":"Legacy HTTP peer — notify only (stub autobuy OFF; real x402 path)","created_at":null}],"register":"POST /api/art/buyers with buyer_agent_id + webhook_url"}