FIZZL

The checks as Claude Code plugins, with their skills and MCP servers: /plugin marketplace add Fizzl13/x402-doctor, then /plugin install x402-doctor@fizzl. Also presign-guard@fizzl, fizzl-agent-wallet@fizzl and ichimoku-signal@fizzl.

• Our open data on Hugging Face: the daily x402 Trust Index (every paid endpoint, its verdict and on-chain payments) and the x402 Agent Safety Bench, free under CC BY 4.0.
• We check 42,000 paid x402 endpoints every day: what works, what breaks, and what happened when we paid random ones.
• x402 on Stellar: 631 paid endpoints, and the asset-field mistake that blocks 7% of them.
• The seven most common x402 seller mistakes, each with the fix as code.
• Circle's Agent Marketplace: two-thirds of the listings take only Gateway payments, and what that means for agents.
• Half the x402 sellers paid on Base were paid only by scanners: who really pays, and where the money goes.
• Who can freeze the money AI agents pay with?: one key or several, for every stablecoin x402 runs on.
• x402 runs on cents, but the money comes from a few big payments: what agents buy, and what that means for limits and prices.
• How to let an AI agent pay without handing it your money: daily limits in code, your approval per payment, no keys at the provider, and a real test.
• Random x402 sellers delivered 74 to 89% of the time; picked ones 46 of 46: what an agent should look for in a service that buys for it.
• MetaMask calls almost every x402 payment a "High-risk approval": what an x402 payment really lets the seller do, and what to check instead.
• 1,382 Algorand routes the newest x402 client can't pay: @x402/avm 2.29.0 takes only the CAIP-2 network id, and the one-line fix for sellers and buyers.
• A tweet in Morse code emptied an AI agent's wallet: how Grok and Bankrbot were tricked, why text filters miss it, and what a check outside the agent does.
• x402's critical SDK flaws: what V12 found, why npm audit stays silent, and the 548 endpoints that ask more than the new $1 default cap.
• Every x402 project fails npm audit: what the zod advisory really means, and why npm audit fix would stop your payments.
• x402 on the XRP Ledger: the payment count fell 98%, the money went up: one seller now paid with Checks, and the fleets behind the payment counts.
• x402 on X Layer: 1,067 paid endpoints, and no payments yet: one seller with 76%, four different dollars, and four days of blocks without a single payment.
• x402 on Stellar: 1,880 endpoints, 398 payments, $3.93: who pays, through which facilitators, and the look-alike payment every new account gets within 15 seconds.
• Let an AI agent buy a paid API it has never used, in one call: finding a seller with a record, checking before paying and after, and today's picks.
• Tools to check an x402 endpoint before an AI agent pays, compared: seven checkers, by the question each one answers.
• Approve AI agent payments in your own wallet with AC2: above its limit, the agent pays only with your signed approval.
• XRPL Batch, delegation, MPTs, vaults and loans: what an agent should check before it signs the XRP Ledger's new transaction types.
• Privy XRPL wallets for AI agents: what the policy checks, and the gap Privy closed in its denylist example after our report.
• An AI support agent that refunds through PayPal: what to check before every refund the Agent Toolkit makes, with a live demo on the PayPal sandbox.