lock_elements · Excalidraw MCP Server MCP: Risk & Policy

WHAT IT DOES

What lock_elements does on Excalidraw MCP Server

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

WHY IT NEEDS A POLICY

Why lock_elements needs a policy

Locking elements is a Write operation because it modifies the state of elements on the canvas in a reversible manner—elements can be unlocked to restore their previous modifiable state. While it prevents further modification of locked elements, the action itself is a property modification, not execution of arbitrary code or irreversible deletion.

From the tool's definition Tool name is 'lock_elements' with description 'Lock elements to prevent modification'. This modifies element properties (lock state) within the Excalidraw canvas, which is a reversible state change.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lock_elements Rate-limited

lock_elements 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": {
    "lock_elements": {
      "limits": [
        {
          "counter": "lock_elements_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 Excalidraw MCP Server, so you can run agents against it safely.

FAQ

Questions about lock_elements

What does the lock_elements tool do? +

Lock elements to prevent modification. It is categorised as a Write tool in the Excalidraw 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 lock_elements? +

Register the Excalidraw MCP Server MCP server in PolicyLayer and add a rule for lock_elements: 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 Excalidraw MCP Server. Nothing to install.

What risk level is lock_elements? +

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

Can I rate-limit lock_elements? +

Yes. Add a rate_limit block to the lock_elements 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 lock_elements completely? +

Set action: deny in the PolicyLayer policy for lock_elements. 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 lock_elements? +

lock_elements is provided by the Excalidraw MCP Server MCP server (kakacoding1/mcp_excalidraw). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.