High Risk →

browser_select

Select an element on the page with index, Either

How to control browser_select ↓

What browser_select does on Search

AI agents invoke browser_select to trigger actions in Search. 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.

High Risk

Why browser_select needs a policy

This tool performs a browser interaction (selecting a UI element) which is an active operation with side effects depending on what element is selected. It falls under Execute as it triggers external browser operations. Severity is medium because selecting elements could trigger form submissions or navigation, but is generally less impactful than code execution.

From the tool's definition 'Select an element on the page with index' — interacts with page elements (e.g., dropdown selection), triggering browser UI actions

Documented attack patterns abuse exactly the kind of access browser_select gives an agent:

How to control browser_select

PolicyLayer is an MCP gateway — it sits between your AI agents and Search, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_select:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_select": {
      "limits": [
        {
          "counter": "browser_select_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

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.

  1. Create a free account and register Search — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

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Related tools and policies

Go deeper

Questions about browser_select

What does the browser_select tool do? +

Select an element on the page with index, Either. It is categorised as a Execute tool in the Search 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 Search 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 Search. 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 Search MCP server (@agent-infra/mcp-server-search). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Search tool call.

Start from Search, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

36 Search tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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