Payment Protocol & Ethereum Integration - HTTP 402 错误代码在 30 多年前被定义为“需要付款”，但从未被广泛使用 [1] - 以太坊通过 x402 和 EIP 3009 赋予 HTTP 402 新的用途 [1] - 服务器现在可以用 USDC 报价，如果代理支付，请求通过；否则，请求被拒绝 [1]

Agent Capabilities - Agents are becoming more prevalent in daily use, including through MCP and pre-defined tool calling [1] - Agents have historically lacked the ability to manage finances, hindering their ability to pay for resources like API calls, storage, inference, or MCP access without human intervention [2] - The introduction of HTTP 402 is changing this limitation [2]