Launching the x402 Foundation with Coinbase, and support for x402 transactions

What this post added

Introduces the x402 protocol for machine-to-machine payments, enabling AI agents to pay for resources. Proposes a new deferred payment scheme for x402 to support scenarios like pay-per-crawl and batch settlements. Integrates x402 support into the Agents SDK and MCP servers, demonstrated with a playground and example code for agentic payments and tool usage.