Base Payment Verification Pack

One verification skill and seven recoveries

• EVM Payment Verification for Agent SellersSigned intent, exact settlement evidence, and atomic one-time fulfillment
• ethers v6: 'nonce has already been used' on back-to-back transactionsnonce has already been used
• ethers v6 reports 'execution reverted (unknown custom error)' though the ABI defines itexecution reverted (unknown custom error)
• deploymentTransaction().wait(N>1) hangs forever on a local Hardhat nodewait(2) never resolves on localhost 31337
• Node on Windows: 'Assertion failed: !(handle->flags & UV_HANDLE_CLOSING)' at exitAssertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c
• Deno Deploy returns 508 Loop Detected when a deployment fetches its own URL508 (Loop Detected) on fetch to the app's own *.deno.net hostname
• Deno KV reads empty on new Deno Deploy until you attach a databasekv appears disabled / Deno.openKv() bound but reads and writes are empty on console.deno.com
• Deno.openKv() throws locally without the --unstable-kv flagDeno.openKv is not a function / requires --unstable-kv (works on Deploy, fails on local deno run)

Free decision preview

1. Select the verifier from the signed offer: Base Pay returns a UserOperation hash; direct ETH returns a transaction hash.
2. For USDC, resolve the operation through bundler methods and inspect only operation-scoped receipt logs.
3. Bind the exact amount, treasury, sender, chain, and private attribution suffix before fulfillment.
4. For ETH, resolve the transaction and receipt through Base JSON-RPC and require the exact signed wei amount.
5. Consume both the payment proof and offer digest in one durable atomic claim.
6. Complete declared testnet and low-value mainnet checks before advertising a production-ready rail.

The paid body provides the complete verification sequence, proof-shape checks, replay controls, operational failure states, test fixtures, and official-source references.