What is ArbiSim Guard?
Last updated: July 2026 · Supported by Ava Labs Retro9000
One sentence
Before any transaction goes to the blockchain, ArbiSim Guard runs it first — on a copy of the live chain — and tells your agent whether it is safe to proceed.
New: Circle Agent Stack integration
Circle Agent Wallets get a native pre-flight policy hook, and agents can pay $0.001 USDC per call with x402 Nanopayments — no API key required.
The problem it solves
AI agents are increasingly making financial decisions on their own. They can swap tokens, pay for services, and move funds across chains — all without a human approving each step.
That autonomy is powerful. But it also means there is nothing to catch mistakes before they happen. A bad transaction is sent, it reverts or executes badly, and by the time the agent notices, money has been wasted or lost.
ArbiSim is that catch. It is a mandatory safety check your agent runs before it sends anything.
How it works in plain English
Your agent has a plan
It wants to execute a transaction — a token swap, a DeFi deposit, an agent-to-agent payment.
It sends that plan to ArbiSim first
Via a simple API call or an MCP tool call. No blockchain interaction happens yet.
ArbiSim runs it on a live copy of the chain
It creates an isolated snapshot of the real blockchain state — real prices, real contracts, real liquidity — and executes your transaction inside that snapshot. Nothing moves.
You get a verdict
APPROVED means the transaction looks safe. REJECTED means ArbiSim found a problem, and it tells you exactly what: the transaction would fail, the price impact is too high, someone is trying to front-run you, etc.
Your agent decides
If approved, it proceeds. If rejected, it aborts and reports back.
Who is this for?
AI agent developers
You are building autonomous agents that interact with DeFi protocols. You need a way to validate transactions before they execute in production.
DeFi protocol teams
You want to offer simulation infrastructure to the agent frameworks integrating with your protocol.
Blockchain BD / investor reviewers
You want to see a live, working safety layer with real integrations on Avalanche and Arbitrum.
Web3 developers new to agents
You want to understand what a transaction will do before you run it. ArbiSim explains the result in plain English.
Supported chains
Avalanche support is funded by the Ava Labs Retro9000 program. Learn about Retro9000 ↗