> For the complete documentation index, see [llms.txt](/llms.txt).

# Security

MetaMask Agent Wallet applies mandatory security on every transaction. Agents cannot opt out of the security pipeline.

## Transaction simulation[​](#transaction-simulation "Direct link to Transaction simulation")

Before a transaction executes, the CLI simulates it to surface reverts, unexpected state changes, and other failures early.

## Transaction Shield (powered by Blockaid)[​](#transaction-shield-powered-by-blockaid "Direct link to Transaction Shield (powered by Blockaid)")

Transaction Shield scans transactions for known threats. Malicious transactions are blocked before they execute. When a transaction is flagged, you receive details in the CLI output and through the approval flow.

## Servo MEV protection[​](#servo-mev-protection "Direct link to Servo MEV protection")

Servo helps protect transactions from sandwich attacks and related MEV extraction where supported on the target chain.

## Cubist TEE-backed key custody[​](#cubist-tee-backed-key-custody "Direct link to Cubist TEE-backed key custody")

In server-wallet mode, private keys are held inside a Cubist trusted execution environment (TEE). Keys are not exposed to the agent process. You retain self-custody and can export your secret recovery phrase when supported by your account configuration.

## Two-factor approval (2FA)[​](#two-factor-approval-2fa "Direct link to Two-factor approval (2FA)")

When a transaction violates your policy or is flagged as high risk, the CLI pauses the job until you approve or reject it. Approval is delivered through:

- MetaMask Mobile push notification, or
- Email link with transaction details

The agent cannot proceed without your approval.

## Guard Mode and Beast Mode[​](#guard-mode-and-beast-mode "Direct link to Guard Mode and Beast Mode")

| Mode                 | Policy enforcement                         | 2FA                                                 |
| -------------------- | ------------------------------------------ | --------------------------------------------------- |
| Guard Mode (default) | Daily spend limits and protocol allowlists | On policy violations                                |
| Beast Mode (opt-in)  | Reduced policy interruptions               | Still required on malicious or flagged transactions |

Configure modes at initialization:

```
mm init --wallet server-wallet --mode guard
mm init --wallet server-wallet --mode beast

```

## Next steps[​](#next-steps "Direct link to Next steps")

- [Choose your wallet mode](/agent-wallet/get-started/choose-wallet-mode/)
- [Architecture](/agent-wallet/concepts/architecture/)