execute_js · DOM Analyzer MCP Server MCP: Risk & Policy

WHAT IT DOES

What execute_js does on DOM Analyzer MCP Server

AI agents invoke execute_js to trigger actions in DOM Analyzer 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 execute_js needs a policy

The tool executes arbitrary JavaScript code directly within a browser context. While the description mentions it is useful for debugging and state inspection, the capability to execute unrestricted JavaScript gives it high blast radius: an AI agent could exfiltrate sensitive data, modify page state maliciously, inject payloads, or trigger unintended side effects depending on what code is executed.

From the tool's definition Tool name 'execute_js' and description stating it 'Esegue JavaScript nella pagina' (Executes JavaScript on the page) and 'returns the result'. This enables arbitrary code execution within a browser environment.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

execute_js Rate-limited

execute_js 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": {
    "execute_js": {
      "limits": [
        {
          "counter": "execute_js_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 DOM Analyzer MCP Server, so you can run agents against it safely.

FAQ

Questions about execute_js

What does the execute_js tool do? +

Esegue JavaScript nella pagina Dom Analyzer e restituisce il risultato (utile per Dom Analyzer state, debug). It is categorised as a Execute tool in the DOM Analyzer 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 execute_js? +

Register the DOM Analyzer MCP Server MCP server in PolicyLayer and add a rule for execute_js: 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 DOM Analyzer MCP Server. Nothing to install.

What risk level is execute_js? +

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

Can I rate-limit execute_js? +

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

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

execute_js is provided by the DOM Analyzer MCP Server MCP server (sudo-elia/dom-analyzer-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.