set_viewport_size · InSite MCP: Risk & Policy

WHAT IT DOES

What set_viewport_size does on InSite

AI agents invoke set_viewport_size to trigger actions in InSite. 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_size needs a policy

This tool changes the browser viewport dimensions, which is a browser state modification that affects subsequent operations. It's not purely reading data, nor is it destructive or financial. It triggers an external operation (browser resize) whose effect is a side effect on the browser engine, placing it in Execute.

From the tool's definition 'Set the browser viewport size' — modifies the state of a running browser session

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_viewport_size Rate-limited

set_viewport_size 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_size": {
      "limits": [
        {
          "counter": "set_viewport_size_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 InSite, so you can run agents against it safely.

FAQ

Questions about set_viewport_size

What does the set_viewport_size tool do? +

Set the browser viewport size. It is categorised as a Execute tool in the InSite 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_size? +

Register the InSite MCP server in PolicyLayer and add a rule for set_viewport_size: 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 InSite. Nothing to install.

What risk level is set_viewport_size? +

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

Can I rate-limit set_viewport_size? +

Yes. Add a rate_limit block to the set_viewport_size 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_size completely? +

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

set_viewport_size is provided by the InSite MCP server (jowharshamshiri/insite). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.