Mysten Labs and Google Cloud launch Verifiable Agent Arbiter to audit AI agents

AI agents are getting permission to book, buy, negotiate and execute on behalf of companies. The awkward question is how anyone proves what those agents actually did.

Mysten Labs and Google Cloud think they have an answer. On October 6, 2026, the two companies unveiled the Verifiable Agent Arbiter (VAA), an evidence layer built to let enterprises cryptographically confirm that their AI agents operated inside the authority they were given.

How the Verifiable Agent Arbiter works

VAA splits agent activity into two tracks. Telemetry such as prompts, outputs, tool calls and policy decisions is stored in Google Cloud Storage buckets that the customer controls.

The cryptographic proofs tied to that activity live elsewhere. They are stored on Walrus, Mysten’s decentralized data platform designed for AI workloads, and coordinated on the Sui Layer-1 blockchain.

That separation is the core design choice. Sensitive business data stays private in the enterprise’s own cloud environment, while the evidence that it hasn’t been altered sits on infrastructure no single party can quietly edit.

Evan Cheng, CEO of Mysten Labs, said VAA is meant to ensure that an AI agent’s authority cannot be exceeded, framing the product as a way to make agent behavior both verifiable and accountable.

Disputes, incidents and agent commerce

VAA is pitched for several jobs beyond simple logging. The first is dispute resolution.

When two agents disagree about what happened in a transaction, VAA can replay the exchange through Google’s open Agent2Agent (A2A) protocol. Google has contributed A2A to the Linux Foundation, which positions it as a shared standard rather than a proprietary Google product.

The second job is incident reconstruction. If an agent goes off the rails or a security event occurs, teams can rebuild the sequence of actions from tamper-evident records instead of piecing together scattered logs.

The third is long-term record retention. Mysten and Google say the stored records are built to be resilient against quantum computing threats.

Finally, VAA plugs into agentic commerce. It integrates with Sui’s Agent Payments facilitator and uses the x402 protocol for service discovery and near-immediate settlement.

The rollout is staged. Initial enterprise deployments come first, with broader access planned afterward.

Why regulators are part of the pitch

The timing is not accidental. The EU AI Act comes into force in 2027, and noncompliance could bring fines of up to €15 million or 3% of global annual turnover.

Background: Sui’s growing Google ties

This isn’t the first time Mysten and Google have lined up. In September 2025, the Sui blockchain added support for Google’s Agentic Payments Protocol (AP2), which focused on letting AI agents handle payments.

VAA extends that relationship from payments into accountability. The first project helped agents spend money. This one helps companies prove the spending was authorized.

VAA also leans on the broader Sui Stack, which includes Sui, Walrus, Seal and Nautilus. Mysten positions the stack as tooling for verifiable execution and data provenance in enterprise settings.

What this means

For enterprises, VAA keeps raw data within the company’s own Google Cloud environment, while the integrity of that data can be checked against public infrastructure.

For the Sui ecosystem, the partnership is a distribution win. Google Cloud brings enterprise relationships that most Layer-1 networks would struggle to reach on their own, and Walrus gets a high-profile workload that matches what it was designed to handle.

Because VAA orchestrates its proofs on Sui and stores them on Walrus, enterprise adoption could translate into more activity on those networks. Whether that happens depends on how many enterprises move past initial deployments, which is not yet known.

The key signals to track are the pace at which VAA moves from initial enterprise deployments to broader availability, how widely the A2A protocol is adopted under the Linux Foundation, and whether agent payments through x402 and Sui’s facilitator gain traction outside of pilots.