web_search · Nav MCP: Risk & Policy

WHAT IT DOES

What web_search does on Navmcp

AI agents invoke web_search to trigger actions in Navmcp. 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 web_search needs a policy

Given the server context (browser automation via Selenium and FastMCP) and sibling tools like fetch_url, click_element, and paper_search, web_search likely triggers browser-based search operations — an external action executed via Selenium. Empty description lowers confidence.

From the tool's definition Tool name: 'web_search'; description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

web_search Rate-limited

web_search 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": {
    "web_search": {
      "limits": [
        {
          "counter": "web_search_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 Navmcp, so you can run agents against it safely.

FAQ

Questions about web_search

What does the web_search tool do? +

web_search. It is categorised as a Execute tool in the Navmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on web_search? +

Register the Nav MCP server in PolicyLayer and add a rule for web_search: 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 Navmcp. Nothing to install.

What risk level is web_search? +

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

Can I rate-limit web_search? +

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

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

web_search is provided by the Nav MCP server (jianlins/navmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.