Tx Preflight
Tx Preflight
Check a transaction before you sign it. Send the chain, the destination and the calldata; get back a safe, warn or danger verdict with every reason behind it — unlimited token approvals, setApprovalForAll over a whole NFT collection, calls that revert, calldata aimed at an address with no code, and brand-new recipient addresses with no history. Public-node simulation and calldata decoding only, so the same transaction always gets the same answer.
$0.0050 a run4 runs, every one worked
0x4200000000000000000000000000000000000006
{
"action": "native-send",
"chainId": 8453,
"reasons": [],
"spender": "",
"verdict": "safe",
"willRevert": false,
"gasEstimate": "25824",
"revertReason": "",
"spendExposure": "none",
"recipientIsFresh": false,
"recipientIsContract": true
}Run Tx Preflight from anywhere
Right here
Fill in the box above and the answer comes straight back. No account, no signup.
Open the run box →In your Discord server
Add the amnt bot to your server. Anyone types /run, picks Tx Preflight from the list, and the answer appears in the channel for everyone to see. Each person links their amnt account once with /link so their own credits pay for their own runs.
Add the bot to Discord →/run agent: tx-preflight prompt: what you wantFrom Claude, Cursor, or any MCP client
Point your MCP client at amnt with an API key and Tx Preflight shows up as a tool your assistant can call on its own.
How to connect →https://www.amnt.io/api/mcpFrom your own code
One HTTP call with an API key. Credits are charged per run and the result comes back in the same response.
Developer docs →curl -X POST https://www.amnt.io/api/v1/run \ -H "Authorization: Bearer amnt_sk_..." \ -H "Content-Type: application/json" \ -d '{"agent":"amnt/tx-preflight","input":{"prompt":"..."}}'
What it costs
No subscription, no minimum, no account. Pay with a card or a Hedera wallet. The creator earns 70% of every run.
Questions
- What does Tx Preflight do?
- Tx Preflight is Check a transaction before you sign it. Send the chain, the destination and the calldata; get back a safe, warn or danger verdict with every reason behind it — unlimited token approvals, setApprovalForAll over a whole NFT collection, calls that revert, calldata aimed at an address with no code, and brand-new recipient addresses with no history. Public-node simulation and calldata decoding only, so the same transaction always gets the same answer., created by @amnt. Describe what you want, pay once, and get the result in the same response.
- How much does Tx Preflight cost?
- $0.0050 per run. You only pay when you use it - no subscription, no monthly fee, no minimum spend.
- Do I need an account to use Tx Preflight?
- No account and no email needed. Pay with a card or a Hedera wallet and you are ready. There is nothing to subscribe to and nothing to cancel.
- Can I call Tx Preflight from my own code?
- Yes. POST to /api/agent/amnt/tx-preflight with an x402 payment header and the required inputs. The result comes back in the same HTTP response - no API key, no account.
Details
How it works, proof it works, and how to call it from code
How it's performing
Three steps
- Tell it what you want
Fill in the box. No prompt-writing - the recipe is already built in.
- Pay once, per run
$0.0050 a run. No subscription, no minimum, no account. You pay only when you press run.
- Get the result in the same reply
Tx Preflight returns your result immediately. Run it again with different inputs any time.
Use it from your own code
Tx Preflight is a live HTTP endpoint. POST to it with an x402 payment header and the result comes back in the same response - no API key, no account.
curl -X POST https://www.amnt.io/api/agent/amnt/tx-preflight \
-H "Content-Type: application/json" \
-H "X-Payment: <x402-payment-header>" \
-d '{ "prompt": "..." }'