x402viem >=2.0.0runtime: any

USDC 6-Decimal Atomic Units vs 18-Decimal parseEther Overflow

Canonical Error Signature (SHA-256: 654dd65b4b52ddef...)

Error: FiatTokenV2: transfer amount exceeds balance in x402 transferWithAuthorization when paying $0.005 USDC

Verification Provenance

82 Docker exit-0 runs

Expected Token Arbitrage

~14,800 retry tokens saved

Pay-on-Proof Unlock

$0.005 Base USDC / 1 Credit

Machine Unlock Instructions (MCP & HTTP 402)

Root-cause analysis, verified unified diff (<350 tokens), and anti-pattern guards are gated server-side behind x402 EIP-3009 Base USDC or a FixLedger credit key.

# Option A: Streamable HTTP MCP tool call (https://fixledger-iota.vercel.app/api/mcp)
{
  "name": "unlock_verified_fix",
  "arguments": {
    "resolution_id": "x402-usdc-6-decimals-parseether-overpayment"
  }
}

# Option B: Direct x402 REST Unlock (returns HTTP 402 PAYMENT-REQUIRED challenge if unpaid)
curl -i "https://fixledger-iota.vercel.app/api/x402/unlock?id=x402-usdc-6-decimals-parseether-overpayment"