upload_file · Chrome Devtools MCP: Risk & Policy

WHAT IT DOES

What upload_file does on Chrome Devtools

AI agents invoke upload_file to trigger actions in Chrome Devtools. 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 upload_file needs a policy

This tool performs a browser action (file upload) through a DOM element in a live Chrome browser. It triggers an external operation whose effects depend on arguments - uploading a file to whatever destination the form element targets. This could result in sensitive data being sent to external servers, making it high severity.

From the tool's definition Upload a file through a provided element

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload_file Rate-limited

upload_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": {
    "upload_file": {
      "limits": [
        {
          "counter": "upload_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 Chrome Devtools, so you can run agents against it safely.

FAQ

Questions about upload_file

What does the upload_file tool do? +

Upload a file through a provided element. It is categorised as a Execute tool in the Chrome Devtools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on upload_file? +

Register the Chrome Devtools MCP server in PolicyLayer and add a rule for upload_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 Chrome Devtools. Nothing to install.

What risk level is upload_file? +

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

Can I rate-limit upload_file? +

Yes. Add a rate_limit block to the upload_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 upload_file completely? +

Set action: deny in the PolicyLayer policy for upload_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 upload_file? +

upload_file is provided by the Chrome Devtools MCP server (shivamprasad99/chrome-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.