browser_type · MCProxy MCP: Risk & Policy

WHAT IT DOES

What browser_type does on MCProxy

AI agents invoke browser_type to trigger actions in MCProxy. 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_type needs a policy

This tool performs a browser action (typing into input fields) that triggers external operations whose effects depend on the arguments provided. It can be used to submit forms, enter credentials, or interact with web applications in ways that cause side effects. The humanized typing feature suggests it's designed to simulate human behavior, which increases potential for misuse.

From the tool's definition Type text into an input element. Supports humanized typing with random keystroke delays.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_type Rate-limited

browser_type 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_type": {
      "limits": [
        {
          "counter": "browser_type_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 MCProxy, so you can run agents against it safely.

FAQ

Questions about browser_type

What does the browser_type tool do? +

Type text into an input element. Supports humanized typing with random keystroke delays. It is categorised as a Execute tool in the MCProxy 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_type? +

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

What risk level is browser_type? +

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

Can I rate-limit browser_type? +

Yes. Add a rate_limit block to the browser_type 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_type completely? +

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

browser_type is provided by the MCProxy MCP server (saladtechnologies/mcproxy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.