update_element · tldraw MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_element does on tldraw MCP Server

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

WHY IT NEEDS A POLICY

Why update_element needs a policy

This tool modifies canvas data reversibly. While it changes element properties, these modifications can be undone through UI actions or subsequent updates. The impact is limited to the canvas state within a tldraw application. It does not delete data (Destructive), execute arbitrary code (Execute), involve financial transactions (Financial), or cause side effects beyond the canvas itself.

From the tool's definition Tool updates existing elements on a tldraw canvas with 'partial update — only provided fields change', allowing modification of diagram properties without deletion or irreversible destruction.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_element Rate-limited

update_element 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": {
    "update_element": {
      "limits": [
        {
          "counter": "update_element_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 tldraw MCP Server, so you can run agents against it safely.

FAQ

Questions about update_element

What does the update_element tool do? +

Update properties of an existing element (partial update — only provided fields change). It is categorised as a Write tool in the tldraw 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 update_element? +

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

What risk level is update_element? +

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

Can I rate-limit update_element? +

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

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

update_element is provided by the tldraw MCP Server MCP server (mihai-codes/tldraw-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.