aid: 4th-heart
name: 4th & Heart
description: '4th & Heart is a California-based consumer packaged goods company that makes grass-fed,
  pasture-raised ghee (clarified butter) and ghee-based spreads, sold direct-to-consumer from its own
  Shopify storefront at fourthandheart.com and through national grocery retail. It is not a software vendor
  and publishes no developer program, but the storefront exposes a real, unauthenticated agent-commerce
  surface: a Universal Commerce Protocol (UCP) merchant profile at /.well-known/ucp, a live Model Context
  Protocol server at /api/ucp/mcp serving 13 catalog, cart, checkout and order tools with full JSON Schema,
  an /llms.txt and /agents.md agent instruction document, and Shopify customer-account OAuth 2.0 / OpenID
  Connect discovery metadata on its own domain.'
image: https://fourthandheart.com/cdn/shop/files/4thandHeartGhee.png?v=1730292913
url: https://raw.githubusercontent.com/api-evangelist/4th-heart/refs/heads/main/apis.yml
specificationVersion: '0.20'
created: '2026-09-05'
modified: '2026-09-05'
tags:
- Company
- Food and Beverage
- Consumer Packaged Goods
- Retail
- E-Commerce
- Agentic Commerce
- Universal Commerce Protocol
- MCP
- Shopify
- Direct to Consumer
tags_raw:
- Company
- Food and Beverage
- Consumer Packaged Goods
- Retail
- E-Commerce
- Agentic Commerce
- Universal Commerce Protocol
- Model Context Protocol
- Shopify
- Direct to Consumer
apis:
- aid: 4th-heart:4th-heart-commerce
  name: 4th & Heart Agentic Commerce (UCP / MCP)
  description: The agent-facing commerce surface of the 4th & Heart online store, implemented by Shopify's
    native Universal Commerce Protocol support on the merchant's own domain. A remote MCP server at https://fourthandheart.com/api/ucp/mcp
    answers tools/list anonymously with 13 tools covering catalog search and lookup, cart lifecycle, checkout
    lifecycle and order retrieval. The UCP merchant profile at /.well-known/ucp declares protocol version
    2026-08-25 with two prior dated versions still served, and the shopping, cart, checkout, fulfillment,
    discount and order capabilities. Checkout completion requires contemporaneous buyer approval.
  image: https://fourthandheart.com/cdn/shop/files/4thandHeartGhee.png?v=1730292913
  humanURL: https://fourthandheart.com/agents.md
  baseURL: https://fourthandheart.com/api/ucp/mcp
  tags:
  - Agentic Commerce
  - MCP
  - Universal Commerce Protocol
  - E-Commerce
  - Catalog
  - Cart
  - Checkout
  tags_raw:
  - Agentic Commerce
  - Model Context Protocol
  - Universal Commerce Protocol
  - E-Commerce
  - Catalog
  - Cart
  - Checkout
  properties:
  - type: MCPServer
    url: mcp/4th-heart-mcp.yml
  - type: Authentication
    url: authentication/4th-heart-authentication.yml
  - type: OAuthScopes
    url: scopes/4th-heart-scopes.yml
  - type: ErrorCatalog
    url: errors/4th-heart-problem-types.yml
  - type: Conventions
    url: conventions/4th-heart-conventions.yml
  - type: DataModel
    url: data-model/4th-heart-data-model.yml
  - type: RateLimits
    url: rate-limits/4th-heart-rate-limits.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://fourthandheart.com/
- type: Documentation
  url: https://fourthandheart.com/agents.md
- type: LLMsTxt
  url: llms/4th-heart-llms.txt
- type: WellKnown
  url: well-known/4th-heart-well-known.yml
- type: MCPServer
  url: mcp/4th-heart-mcp.yml
- type: Conformance
  url: conformance/4th-heart-conformance.yml
- type: Lifecycle
  url: lifecycle/4th-heart-lifecycle.yml
- type: DomainSecurity
  url: security/4th-heart-domain-security.yml
- type: Plans
  url: plans/4th-heart-plans-pricing.yml
- type: RateLimits
  url: rate-limits/4th-heart-rate-limits.yml
- type: AgentSkill
  url: skills/_index.yml
- type: Blog
  url: https://fourthandheart.com/blogs/recipes
- type: Support
  url: https://fourthandheart.com/pages/contact-us
- type: SignUp
  url: https://fourthandheart.com/account/login
- type: TermsOfService
  url: https://fourthandheart.com/policies/terms-of-service
- type: PrivacyPolicy
  url: https://fourthandheart.com/policies/privacy-policy
x-enrichment:
  date: '2026-09-05'
  status: enriched
  artifacts_added: 19
  pass: local-v3