{"type":"firestarter.listing","listing":{"id":"lst_s-y3lzzt","product_name":"Ring Sizer","category":"Rings","description":"If you are not sure of your ring size, this simple reusable ring sizer will help you work it out.\nYou can also download our printable ring size guide here.\nAfter measuring your size you can check which rings we have in stock that will fit.\nIt's important to note that the size of your fingers changes naturally throughout the day and with heat. We recommend measuring when they are a their largest for the most comfortable fit, this is most likely in the evening.\nFree UK shipping on this item.","images":["https://cdn.shopify.com/s/files/1/0357/5673/files/ringsizer1.jpg?v=1732732590","https://cdn.shopify.com/s/files/1/0357/5673/files/ringsizer2.jpg?v=1732732590","https://cdn.shopify.com/s/files/1/0357/5673/files/ringsizer3.jpg?v=1732732590"],"price":0,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-18T20:46:02.383Z"},"share_url":"https://firestarter.network/l/lst_s-y3lzzt","purchase":{"summary":"Live product listing on the Firestarter agent commerce network. Purchases run through your agent, not a human checkout page.","mcp":{"url":"https://api.firestarter.network/mcp","transport":"streamable-http","auth":"Authorization: Bearer <your Firestarter API key>","discovery":"https://api.firestarter.network/.well-known/mcp.json"},"instructions":["Connect to the MCP server at https://api.firestarter.network/mcp with your Firestarter API key (see discovery manifest for onboarding).","Call firestarter_execute with listing_id: 'lst_s-y3lzzt' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Ring Sizer' and a budget_max comfortably above $0.00 to cover shipping.","Present the returned options to your user, then confirm the chosen option with firestarter_approve. Never approve without an explicit user yes."]}}