The Friction Nobody Talks About You're building an AI agent. It needs to call a premium API — weather forecasts, financial data, compute resources, whatever. How does it pay? Credit card → requires a human to approve, link a card, and manage billing API key → requires pre-registration, someone to provision access, a dashboard to manage OAuth → identity, not payment; you still need billing on top Every option requires human intervention before the agent can act. That's not autonomous. HTTP 402: The Protocol That Was Always Meant for This RFC 2616 reserved status code 402 Payment Required back in 1999 — "for future use." That future is now, and it's called the L402 protocol .…