set_viewport · tldraw MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_viewport does on tldraw MCP Server

AI agents invoke set_viewport to trigger actions in tldraw MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why set_viewport needs a policy

This tool manipulates the viewport state of a live tldraw canvas — scrolling and zooming — which constitutes triggering an external operation (UI state change) rather than simply reading data or writing persistent content. It falls under Execute as it controls the live canvas environment. Misuse has moderate blast radius since it affects the view but not the underlying data.

From the tool's definition 'Control the canvas viewport' and 'zoom-to-fit' indicate triggering external operations on a live canvas

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_viewport Rate-limited

set_viewport stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_viewport": {
      "limits": [
        {
          "counter": "set_viewport_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 set_viewport

What does the set_viewport tool do? +

Control the canvas viewport. Use scrollToContent to zoom-to-fit,. It is categorised as a Execute tool in the tldraw MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on set_viewport? +

Register the tldraw MCP Server MCP server in PolicyLayer and add a rule for set_viewport: 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 set_viewport? +

set_viewport is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit set_viewport? +

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

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

set_viewport 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.