undo

THE RISK

Critical Risk

Why undo needs a policy

Undo reverses a previous action in the editor, which could irrecoverably remove work or changes that were intentionally made. While 'undo' sounds benign, in an automated/AI context it can irreversibly discard intentional edits, effectively destroying state. It's not a simple write since it rolls back changes rather than creating or modifying data forward.

From the tool's definition Undo the last editor action via the transaction system

Documented attack patterns abuse exactly the kind of access undo gives an agent:

POLICY

How to control undo

PolicyLayer is an MCP gateway — it sits between your AI agents and Uefn, and nothing reaches the server without passing your rules. This is the rule we recommend for undo:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "undo"
  ]
}

undo disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Uefn — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Uefn tools

Destructive delete_actors Delete actors by their labels. Destructive delete_asset Delete an asset. Destructive tag_remove tag_remove Destructive shutdown Stop the MCP listener. Destructive snapshot_restore Restore the level to a previously saved snapshot state. Execute batch_exec Execute multiple bridge commands in a single editor tick — faster than sending one-by-one. Execute blueprint_compile Compile a Blueprint asset and return compilation status. Execute device_sim_trigger_method Trigger a discoverable method on the selected Verse device via Python API.

All 143 Uefn tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in Uefn → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about undo

What does the undo tool do? +

Undo the last editor action via the transaction system. It is categorised as a Destructive tool in the Uefn MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on undo? +

Register the Uefn MCP server in PolicyLayer and add a rule for undo: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Uefn. Nothing to install.

What risk level is undo? +

undo is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit undo? +

Yes. Add a rate_limit block to the undo rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block undo completely? +

Set action: deny in the PolicyLayer policy for undo. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides undo? +

undo is provided by the Uefn MCP server (quangdang46/uefn-verse-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Uefn tool call.

Start from Uefn, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →