undo · AI-Canvas MCP Server MCP: Risk & Policy

WHAT IT DOES

What undo does on AI-Canvas MCP Server

AI agents use undo to create or update resources in AI-Canvas MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AI-Canvas MCP Server environment.

WHY IT NEEDS A POLICY

Why undo needs a policy

While 'undo' restores prior state, it is fundamentally a write operation that modifies the current design document. It does not delete data irreversibly (Destructive category), but it does change document state. Severity is medium because misuse could revert intentional changes, but the operation is itself reversible via redo.

From the tool's definition Tool named 'undo' with description 'Undo the last operation' – reverses a modification to design state, restoring a previous state. This is a write-class operation (modifies design documents) that is reversible (can be re-done).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

undo Rate-limited

undo stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "undo": {
      "limits": [
        {
          "counter": "undo_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches AI-Canvas MCP Server, so you can run agents against it safely.

FAQ

Questions about undo

What does the undo tool do? +

Undo the last operation. It is categorised as a Write tool in the AI-Canvas MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on undo? +

Register the AI-Canvas MCP Server 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 AI-Canvas MCP Server. Nothing to install.

What risk level is undo? +

undo is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

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 AI-Canvas MCP Server MCP server (laoluojuhai/ai-canvas). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.