{"type":"firestarter.listing","listing":{"id":"lst_4_Hi2XtL","product_name":"Chest Expander","category":"Strength Training Accessory","description":"Don't let the name fool you: this bodybuilding classic targets the back, triceps, biceps, and more. It's been a staple in bodybuilding for over a century for its effectiveness and versatility in building lean, defined muscle with that wiry, natural look.Built for progression, this steel contraption has 7 springs with carabiner attachments, so you can remove or double up springs, adjusting the tension to suit your goals and experience level. When fully stretched, each spring provides 20lbs of resistance.Beginners and pros alike can use this for curls, flyes, and rows or attach to a fixed point for presses. Grab two for even more versatility (shameless upsell!)The chest expander offers consistent tension throughout the movement regardless of how many springs are attached, making it optimal over bands for bodybuilding.The design hasn't changed much over the past century because it hasn't needed to, but we've thrown on rotating handles and knurling for that cherry on top of a swole sundae.Watch your arm hair, though—and if you see Kaevon walking around looking smoother than a baby porpoise, mind your business.IMPORTANT: Use a minimum of two springs on opposing ends of the handles to avoid over-stretching them. The warranty on the springs is 3 months, as they are considered a perishable item.","images":["https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-1.jpg?v=1764594232","https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-2.jpg?v=1764594232","https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-3.jpg?v=1764594232","https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-4.jpg?v=1764594232","https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-5.jpg?v=1764594232","https://cdn.shopify.com/s/files/1/0654/3346/9125/files/EXPANDER-carousel-6.jpg?v=1764594232"],"price":73.99,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-18T20:46:45.793Z"},"share_url":"https://firestarter.network/l/lst_4_Hi2XtL","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_4_Hi2XtL' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Chest Expander' and a budget_max comfortably above $73.99 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."]}}