UCPStoreDocs
Protocol Fundamentals

Core Capabilities

Capabilities are the fundamental building blocks of UCP. They define the core commerce operations that every UCP-compatible system must support.

What are Capabilities?

Capabilities represent the essential commerce operations that must be supported by any UCP-compatible business. They provide the foundation for all commerce interactions between platforms, agents, and businesses.

Each capability has a unique namespace identifier (e.g., dev.ucp.shopping.checkout) that allows agents to verify support before initiating transactions.

Available Capabilities

Checkout

dev.ucp.shopping.checkout

Create, manage, and complete checkout sessions. Handles cart management, tax calculation, and payment processing.

Key Features

  • Create and manage checkout sessions
  • Cart management and modification
  • Tax calculation and totals
  • Multiple payment handler support
  • Completion and cancellation flows
View documentation

Identity Linking

dev.ucp.common.identity_linking

OAuth 2.0-based authorization enabling platforms to perform actions on behalf of users.

Key Features

  • OAuth 2.0 authorization flows
  • Account linking between platforms
  • Access to loyalty programs
  • Personalized offers and pricing
  • Secure token management
View documentation

Order

dev.ucp.shopping.order

Webhook-based lifecycle management for orders, including fulfillment tracking and post-purchase operations.

Key Features

  • Webhook-based order updates
  • Line item tracking
  • Fulfillment event management
  • Returns and refunds
  • Dispute handling
View documentation

Capability Declaration

Businesses declare their supported capabilities in their profile:

{
  "capabilities": [
    "dev.ucp.shopping.checkout",
    "dev.ucp.common.identity_linking",
    "dev.ucp.shopping.order"
  ]
}

Capability Versioning

Each capability follows semantic versioning. When breaking changes are introduced, the namespace is updated (e.g., dev.ucp.shopping.checkout.v2). Platforms should check capability versions before initiating transactions.

Next Steps

Learn about each capability in detail:

Protocol OverviewExtensions
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