maximize_browser · Selenium MCP Server MCP: Risk & Policy

WHAT IT DOES

What maximize_browser does on Selenium MCP Server

AI agents invoke maximize_browser to trigger actions in Selenium 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 maximize_browser needs a policy

This tool controls a real browser window state through Selenium WebDriver. While it only resizes the window and has no data side effects, it executes an external browser operation. The blast radius is low since it only affects window display size, but it falls under Execute as it triggers an action in an external system (the browser).

From the tool's definition 'Maximize the browser window' — triggers an external browser operation via Selenium WebDriver

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

maximize_browser Rate-limited

maximize_browser 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": {
    "maximize_browser": {
      "limits": [
        {
          "counter": "maximize_browser_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 Selenium MCP Server, so you can run agents against it safely.

FAQ

Questions about maximize_browser

What does the maximize_browser tool do? +

Maximize the browser window. It is categorised as a Execute tool in the Selenium 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 maximize_browser? +

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

What risk level is maximize_browser? +

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

Can I rate-limit maximize_browser? +

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

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

maximize_browser is provided by the Selenium MCP Server MCP server (nayakprashant/selenium-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.