txKit

txKit makes AI-agent transactions safe to allow. Verify before you sign.

THE PROBLEM

AI agents are gaining write access to crypto wallets. Today an agent receives an intent, builds a transaction, and signs it - the user sees a hex blob, or nothing at all, until funds have moved. There is no standard requiring an agent to disclose what a transaction will do, and no on-chain policy engine the agent cannot circumvent. Blind signing has already drained billions from users; txKit stops it from being automated at agent scale.

THE SOLUTION - three interlocking layers

1. ERC-8265 Prepared Transaction Envelope (Ethereum PR #1753): a typed, unsigned bundle the agent builds before any signing, carrying the decoded function, declared value, expiry, policy metadata, and an EIP-712 binding to the authorised agent signer. The user sees this, not calldata. txKit is the reference implementation, authored by Mike Diamond.

2. AgentPolicyGate (on-chain): a Solidity contract that enforces five rules on every executeEnvelope call - forwarded value matches the declared value, envelope not replayed, recipient allow-listed, value within the spend cap, and the EIP-712 signature recovers to the configured agent signer. A rogue or compromised agent runtime cannot bypass it; the agent never holds a private key.

3. txKit UI: a Next.js dApp that shows a plain-language preview - function, decoded arguments, Arbitrum sequencer-fee and L1-calldata breakdown, expiry, and policy verdict. The user approves once; the transaction executes.

TWO LIVE DEMOS (end to end on testnet)

Pendle yield swap on Arbitrum Sepolia (demo.txkit.dev/yield-swap): a Claude agent turns the intent "Swap 100 USDC for PT-stETH" into an envelope; the gate executes the swap.

x402-paid RWA buy on Robinhood Chain testnet (demo.txkit.dev/rwa-buy): "Buy 5 TSLA" behind an x402 micropayment paywall; the gate executes the buy and settles a real on-chain mxUSD transfer to the merchant treasury.

LIVE ON-CHAIN (every executeEnvelope returned status 0x1; 27 Forge tests passing)

Arbitrum Sepolia (421614): AgentPolicyGate 0x3A9DaED4...412A5, verified source on Arbiscan.

Robinhood Chain (46630, Arbitrum Orbit): AgentPolicyGate 0x0d4E461d...4d35, all contracts verified on Blockscout; the RWA buy settles a real ERC-20 mxUSD transfer (tx 0xa4736fe7...).

ARBITRUM AND ORBIT FIT

The preview exposes the Arbitrum sequencer-fee and L1-calldata breakdown natively, a data point that does not exist on L1. The same envelope and gate ran on Robinhood Chain (Arbitrum Orbit) with zero code change.

HONEST SCOPE

Deterministic mock routers (real gate path, mock swap and RWA payload). x402 verification is real with an on-chain mxUSD settlement leg; the hosted facilitator is self-hosted because Coinbase's does not support Orbit chains. Testnet only, no user funds at risk. ERC-8265 is an active draft (PR #1753), community-reviewed, awaiting editor review.

Live demo: demo.txkit.dev | Code: github.com/txkit/mono/tree/main/examples/arbitrum-london