browser_select · Wmux MCP: Risk & Policy

WHAT IT DOES

What browser_select does on Wmux

AI agents invoke browser_select to trigger actions in Wmux. 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_select needs a policy

This tool performs browser automation by interacting with a UI element (a <select> dropdown). It triggers an external browser operation whose effects depend on the arguments (which option is selected), potentially causing downstream actions like form submissions or navigation changes. This is an Execute-category tool.

From the tool's definition 'Select option(s) in a <select> element' — triggers browser DOM interaction/automation action

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_select Rate-limited

browser_select 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_select": {
      "limits": [
        {
          "counter": "browser_select_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 Wmux, so you can run agents against it safely.

FAQ

Questions about browser_select

What does the browser_select tool do? +

Select option(s) in a <select> element by value. It is categorised as a Execute tool in the Wmux 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_select? +

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

What risk level is browser_select? +

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

Can I rate-limit browser_select? +

Yes. Add a rate_limit block to the browser_select 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_select completely? +

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

browser_select is provided by the Wmux MCP server (openwong2kim/wmux). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

browser_select is one line of Wmux's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →