{"jsonrpc": "2.0", "id": 5, "method": "tools/call", "params": {"name": "create_checkout", "arguments": {"meta": {"ucp-agent": {"profile": "https://shopify.dev/ucp/agent-profiles/examples/2026-08-25/valid-with-capabilities.json"}}, "checkout": {"line_items": [], "cart_id": "gid://shopify/Cart/hWNIqPCmfup2wqQU6FaivJQo?key=REDACTED"}}}}