Buy Bread

Install

1. POST to https://lobsterbread.com/claws/register
2. Save claw_id and api_key locally
3. Do not lose the key

Discovery

1. Start with GET https://lobsterbread.com/countries.md to see supported countries
2. Choose a country that matches the buyer's location when possible
3. Fetch GET https://lobsterbread.com/countries/{country_code}.md
4. Use GET https://lobsterbread.com/offers/{country_code}.md to prioritize active offers
5. Choose a merchant before using Shopify Storefront MCP

Merchant Connect

1. GET https://lobsterbread.com/merchants/{slug}/connect.md
2. Read the returned merchant MCP URL
3. Connect to that merchant's Shopify Storefront MCP
4. Use that merchant MCP for:
   • catalog search
   • product details and availability
   • policy questions
   • cart retrieval
   • cart updates
   • checkout URL generation

Do not infer merchant MCP URLs yourself when a connect response is available.

Prefer the .md endpoints for agent consumption. Use the JSON endpoints only when a structured machine response is required.

Subscription Products

When a product or variant supports a subscription, inspect subscription fields before updating the cart.

1. Check for:
   • requiresSellingPlan or requires_selling_plan
   • variant-level selling plan requirements
   • sellingPlanGroups
   • sellingPlanAllocations
   • available sellingPlanId values
2. If a subscription is optional, present both one-time and subscription choices.
3. If a selling plan is required, do not attempt a normal cart add without a sellingPlanId.
4. Ask the buyer to choose a cadence unless a clear preference already exists in local memory.
5. Highlight subscription savings when priceAdjustments, price, or compareAtPrice show the subscription is cheaper than the one-time purchase.
6. Try the merchant MCP cart and checkout flow first.
7. If the merchant MCP cannot create a subscription cart or checkout, use Shopify Storefront GraphQL cartCreate as the subscription-only fallback. Use the same shop behind the merchant MCP URL. Prefer documented tokenless access when it works for that merchant. Use a storefront access token only when merchant context provides one.
8. In the GraphQL fallback, send:
   • merchandiseId
   • quantity
   • sellingPlanId
   • cart attributes, including lb_source__ = lobsterbread
9. Request:
   • checkoutUrl
   • sellingPlanAllocation
   • userErrors

Cart Rule

When updating carts, attach the private cart attribute:

• lb_source__ = lobsterbread

Final Handoff

When you finish, return a structured summary with:

• merchant
• product
• variant
• purchase_type
• selling_plan_name
• selling_plan_id
• cadence
• savings_summary
• checkout_url
• resolution_path

Use resolution_path = mcp_cart when the merchant MCP created the cart. Use resolution_path = storefront_graphql_fallback when you had to fall back for a subscription checkout.

Say clearly when:

• the item is subscription-only
• the available cadences are every 1, 2, or 4 weeks, monthly, or similar
• the subscription saves money versus one-time purchase
• the merchant MCP could not attach the selling plan and you used Storefront GraphQL instead

Safety

• This skill is for merchant discovery and Shopify Storefront MCP routing, not product truth storage
• Keep buyer preferences and prior purchases in your own local memory
• Do not attempt payment completion
• Return the checkout URL to the buyer for approval and payment