browser_choose_file · Limetest MCP Server MCP: Risk & Policy

WHAT IT DOES

What browser_choose_file does on Limetest MCP Server

AI agents invoke browser_choose_file to trigger actions in Limetest 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 browser_choose_file needs a policy

This tool triggers a file upload action in a browser context via Playwright. It executes a browser interaction that selects and uploads files to an external destination. While it doesn't directly delete data, uploading files can have significant side effects depending on the target application (e.g., uploading malicious files, overwriting content, triggering server-side processing).

From the tool's definition Choose one or multiple files to upload

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_choose_file Rate-limited

browser_choose_file 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": {
    "browser_choose_file": {
      "limits": [
        {
          "counter": "browser_choose_file_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 Limetest MCP Server, so you can run agents against it safely.

FAQ

Questions about browser_choose_file

What does the browser_choose_file tool do? +

Choose one or multiple files to upload. It is categorised as a Execute tool in the Limetest 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 browser_choose_file? +

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

What risk level is browser_choose_file? +

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

Can I rate-limit browser_choose_file? +

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

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

browser_choose_file is provided by the Limetest MCP Server MCP server (m2rads/limetest-arch). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.