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Lumen Pre-Sign Check
x402
Lumen Pre-Sign Check is a paid API for AI agents from lumenworks-x402-decoder.onrender.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Analyzes an EVM transaction or EIP-712 message before signing and returns a human-readable summary, risk flags, and a verdict on whether it is safe to sign.
Price / call$0.002
Success—
StatusUnknown
How this service works
Lumen Pre-Sign Check: call before signing any EVM transaction or EIP-712 message. Returns {summary, flags[], verdict} (looks_ok | review | do_not_sign_unless_intended). Flags unlimited approvals, Per…
Output
Returns a JSON object with: a plain-English summary array describing what the transaction does, a verdict field (looks_ok | review | do_not_sign_unless_intended), an array of flags with code, level, and message for each detected risk (e.g. UNLIMITED_APPROVAL at high severity), the decoded calldata including function signature and arguments, a label for the target contract if known, and a disclaimer noting this is informational only.
Example use cases
Unlimited approval risk detection
“I'm about to sign a token approval transaction with calldata 0x095ea7b3000000000000000000000000<spender>ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff to contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 — can you check if this is an unlimited approval and tell me whether I should sign it?”
DeFi swap pre-sign safety check
“My wallet is asking me to sign a transaction to 0xDef1C0ded9bec7F1a1670819833240f027b25EfF with some swap calldata — can you decode what function it's calling and flag any risks before I approve it?”
EIP-712 phishing detection
“I got a signature request that looks like an EIP-712 typed message — can you decode it, tell me what I'd actually be agreeing to, and flag whether it looks like a phishing attempt or is safe to sign?”
Technical details
Endpoint
POSThttps://lumenworks-x402-decoder.onrender.com/v1/tx/explain?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent or wallet interface needs to explain and risk-assess an EVM transaction or EIP-712 typed-data signature request before the user signs it. It is the right choice when you want a human-readable breakdown of what a transaction does, automated detection of high-risk patterns like unlimited token approvals, and a clear verdict without needing to simulate on-chain state or run a full security audit.
Side effects
- Unrecognized function selector returns partial decode with no signature match
- Malformed calldata causes decode failure or empty candidates array
- Unknown contract address returns no label or context
- EIP-712 message with non-standard types may produce incomplete risk notes
- Network or server unavailability returns 5xx error
- Missing required fields in request body returns 4xx validation error
Output
Schema · Response
{
"type": "json",
"example": {
"to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"kind": "transaction",
"risk": "high",
"flags": [
{
"msg": "Unlimited token approval: spender can drain this token at any time.",
"code": "UNLIMITED_APPROVAL",
"level": "high"
}
],
"summary": [
"Approve 0x111111125421cA6dc452d289314280a0f8842A65 (1inch v6 Router) to spend UNLIMITED units of token 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
],
"toLabel": "USDC (Base)",
"verdict": "do_not_sign_unless_intended",
"calldata": {
"source": "built-in",
"decoded": {
"args": [
"0x111111125421cA6dc452d289314280a0f8842A65",
"115792089237316195423570985008687907853269984665640564039457584007913129639935"
],
"signature": "approve(address,uint256)"
},
"selector": "0x095ea7b3",
"candidates": [
{
"args": [
"0x111111125421cA6dc452d289314280a0f8842A65",
"115792089237316195423570985008687907853269984665640564039457584007913129639935"
],
"signature": "approve(address,uint256)"
}
],
"signaturesFound": 1
},
"valueWei": "0",
"disclaimer": "Informational, not a security guarantee. looks_ok does not mean safe. No simulation, no on-chain state (proxy implementations, spender code, balances) is checked."
}
}Tags
x402
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