Monad testnet · live

A transaction seatbelt
for Monad.

// a screenshot can lie. a receipt can't.

On Monad you pay for the gas limit you declare, not the gas you use, and even when your transaction reverts. Reckon pre-flights every transaction: it simulates it, refuses to broadcast doomed ones, and sets the tightest correct gas limit.

tx.send()reckon.preflight()OKgas: 23,838BLOCK0 MON spentnaive agent burned0.0408 MONreckon-guarded spent0.0024 MON
94.04%
less MON burned by a Reckon-guarded agent
100%
of failed txs charge the full gas limit on Monad
3
surfaces: SDK · MCP agent guard · on-chain
42
tests, all against live testnet + local EVM
01

The problem: you pay for the limit, not the usage

Ethereum-model chains charge you for the gas your transaction actually consumed. Monad charges you for the gas limit you declared, whether you used it or not, and even when the transaction reverts. Set a loose limit (or let your wallet pad one for you) and you overpay on every single send.

$112.7K
burned by one Monad airdrop recipient on failed txs
~6%
of Monad testnet transactions fail (vs 0.9% on Ethereum)
same transaction. true execution cost: 23,838 gas.other EVM chains charge23,838 gas usedMonad charges (a naive 200k limit)200,000 gas limitthe red is pure overpay, charged even if the tx reverts.
02

Three surfaces, one seatbelt

The same pre-flight engine, wherever your transactions originate from.

packages/sdk

Drop-in SDK

A viem wrapper: preflight(), safeSend(), and batch routing through the on-chain guard. Optionally learns a per-contract gas buffer from real chain history instead of a flat percentage. Add the seatbelt to any dApp or deploy script.

packages/agent

MCP agent guard

An MCP server exposing reckon_preflight so any AI agent checks every transaction before sending. It blocks reverts and flags permission-escalating calls (unlimited approvals, NFT operator grants) even when they'd succeed, the pattern behind a real ~$175K agent-drain incident.

contracts/

On-chain GuardedExecutor

Bounded, predictable execution with per-caller policy, enforced on-chain outside any agent's control. EIP-7702 friendly.

03

Proof, not a promise

A real autonomous agent, run twice on live testnet: once naive, once Reckon-guarded.

Every number is a real balance delta, every hash is a real testnet transaction. No mocked state, anywhere.

See the full on-chain evidence →