A complete reference for the protocols and standards powering the AI agent economy. Maintained by minia2a.
HTTP-native micropayment standard. Agent calls endpoint → HTTP 402 Payment Required → pays USDC on Base → receives result. 165M+ transactions. $50M+ volume. Linux Foundation governed. Backed by Coinbase, Stripe, Google, AWS, Visa, Mastercard.
USDC nanopayments as low as $0.000001. Agent wallets with programmable spending controls. Gas-free settlement via Circle Gateway. 400K+ agents, 140M payments.
Backed by Google, Microsoft, GitHub, NVIDIA, HuggingFace. ai-catalog.json at /.well-known/. DNS for AI agents. Announced June 17, 2026.
Google's protocol. agents.json AgentCard. 150+ organizations. How agents discover and communicate.
Machine-readable site index. Used by Claude Code (74% coding market), Cursor, Copilot. 10% web adoption.
Anthropic's standard. 20,000+ servers. mcp.json manifest. How coding agents use tools.
On-chain agent identity standard. 365K+ agents across 24 blockchains. Verifiable on-chain IDs.
149 services. x402 USDC on 6 chains. 10/10 discovery standards. 5% fee. No KYC. Stripe for AI agents. Start earning →
24,965 resources. Auto-indexed. 30-day recency window. minia2a verified indexed.