onyx_tx_preflight

Active

declared in 1.26.0

Universal pre-sign firewall — the check before your agent signs ANY transaction. Give the tx (to, data, value); Onyx decodes the 4-byte selector + args, tells you in plain terms what it does, and flags the wallet-drain patterns: unlimited approve(), setApprovalForAll (blanket NFT approval), transfers to fresh/EOA recipients, raw ETH sends to unknown addresses, and calls to unverified targets. Returns a SIGNED ALLOW/REVIEW/BLOCK + human explanation. The single highest-frequency safety gate an on-chain agent has — every signed tx should pass through it. (price: $0.10 USDC, tier: metered)

Parameters schema

{
  "type": "object",
  "required": [
    "to"
  ],
  "properties": {
    "to": {
      "type": "string",
      "description": "The transaction's `to` address (target contract or recipient). Required."
    },
    "data": {
      "type": "string",
      "description": "The transaction calldata (0x-hex). Omit/empty for a plain ETH transfer."
    },
    "value_wei": {
      "type": "string",
      "description": "Optional. ETH value being sent, in wei (base-10 string)."
    }
  }
}

What this tool wraps· 1 endpoint

min confidence0.70 0.50

Packagepypi: x402
declared dependency0.85

Parent server

onyx-paid-mcp

https://github.com/dimitrilaouanis-tech/onyx-mcp

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