{"type":"firestarter.listing","listing":{"id":"lst_w51Rf8GQ","product_name":"Extradimensional Umber","category":"Ink Bottle","description":"An ultra-saturated quasi-sheening sepia, Extradimensional Umber bends the color wheel. With a robust sepia base and a hint of green sheen at the right angle, stretching to sandy caramel on a speedier stroke, this hue will surely be one of the most mind-bending in your collection. \nWARNING: Photographing the character in this ink is difficult. I've done my best to capture the extradimensional nuance, but you're bound to find something new as you play with stronger and weaker saturations on different papers in various lighting atmospheres. Our ink swatch is produced with a cotton swab on Tomoe River paper. \nSince this is an extremely saturated ink, some pens may operate on the dry side and extra effort may be required in cleaning. Extradimensional Umber is part of the Keystone Formula fountain pen ink line, built with water soluble dye-colorants. The 90mL volume will provide approximately 112 standard converter refills assuming a 0.8mL draw. ","images":["https://cdn.shopify.com/s/files/1/1237/1088/files/Extradimensional_Umber_Swatch.jpg?v=1779906590","https://cdn.shopify.com/s/files/1/1237/1088/files/Extradimensional-Umber-writing.jpg?v=1769716434","https://cdn.shopify.com/s/files/1/1237/1088/files/Extradimensional_Umber_e0e276b2-fef2-4596-bafd-cd3b209e0a93.jpg?v=1779376538","https://cdn.shopify.com/s/files/1/1237/1088/files/InkBottleBox_5cbc711b-cd36-4030-9af7-856998c4e79b.jpg?v=1769716434"],"price":29,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-18T20:47:18.475Z"},"share_url":"https://firestarter.network/l/lst_w51Rf8GQ","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_w51Rf8GQ' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Extradimensional Umber' and a budget_max comfortably above $29.00 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."]}}