构建通用商业协议
Commerce is humanity's longest-running trade. Universal, but not uniform. We've spent 20+ years at Shopify learning just how complex it is—billions of transactions, millions of merchants—and it continues to humble us: payment options and rules differ based on properties of the cart, buyer, and market; discounts have stacking and combination rules that can rival the tax code; fulfillment options explode with runaway permutations; and the list goes on. This complexity is not a bug, it’s an emergent property of diverse retailers.
商业是人类持续时间最长的贸易。普遍，但不统一。我们在Shopify的20多年经验中学习到它的复杂性——数十亿笔交易、数百万商家——它继续让我们谦卑：支付选项和规则基于购物车、买家和市场的属性而不同；折扣有堆叠和组合规则，可能媲美税法；履约选项随着失控的排列组合而爆炸；而且列表还在继续。这种复杂性不是bug，而是多样化零售商的涌现属性。
Universal Commerce Protocol (UCP) is designed to model this reality with flexibility in mind. We co-developed UCP with Google to create an open standard for AI agents to connect and transact with any merchant.
Universal Commerce Protocol (UCP) 旨在以灵活性为重点来模拟这一现实。我们与 Google 共同开发了 UCP，以创建 AI 代理与任何商家连接和交易的开放标准。
Merchants declare and define what capabilities they support, including their own bespoke functionality. Agents discover these capabilities, negotiate what they can handle, and proceed to complete transactions. UCP defines the discovery and negotiation mechanisms between agent and merchant, as well as the core capabilities that make commerce programmable for agents and humans alike.
商家声明并定义它们支持的能力，包括它们自己的定制功能。代理发现这些能力，协商它们能处理的范围，并继续完成交易。UCP定义了代理与商家之间的发现和协商机制，以及使商业对代理和人类同样可编程的核心能力。
Capabilities and extensions
功能和扩展
Monolithic protocols eventually collapse under complexity: too rigid to adapt, too slow to evolve. Thoughtfully layered protocols survive and thrive by separating responsibilities, defining clear APIs, and enabling composition. TCP/IP proved this and UCP applies this pattern to commerce, separating responsibilities into layers:
单体协议最终会在复杂性下崩溃：太僵硬无法适应，太慢无法演进。深思熟虑的分层协议通过分离职责、定义清晰的API并启用组合来生存和繁荣。TCP/IP证明了这一点，UCP将这种模式应用于商业，将职责分离到层中：
- Shopping service defines core transaction primitives: checkout session, line items, tot...