fetch_file · Local Search MCP Server MCP: Risk & Policy

WHAT IT DOES

What fetch_file does on Local Search MCP Server

AI agents use fetch_file to create or update resources in Local Search MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Local Search MCP Server environment.

WHY IT NEEDS A POLICY

Why fetch_file needs a policy

This tool fetches an external file and writes it into the local search index. It creates/modifies index state by adding a new document, making it a Write operation. Misuse could pollute the index with malicious or unwanted content, giving it medium severity.

From the tool's definition Download a single file from a URL and add it to the searchable index

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fetch_file Rate-limited

fetch_file stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "fetch_file": {
      "limits": [
        {
          "counter": "fetch_file_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Local Search MCP Server, so you can run agents against it safely.

FAQ

Questions about fetch_file

What does the fetch_file tool do? +

Download a single file from a URL and add it to the searchable index. Returns job ID for progress tracking. It is categorised as a Write tool in the Local Search MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fetch_file? +

Register the Local Search MCP Server MCP server in PolicyLayer and add a rule for fetch_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 Local Search MCP Server. Nothing to install.

What risk level is fetch_file? +

fetch_file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit fetch_file? +

Yes. Add a rate_limit block to the fetch_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 fetch_file completely? +

Set action: deny in the PolicyLayer policy for fetch_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 fetch_file? +

fetch_file is provided by the Local Search MCP Server MCP server (patrickruddiman/local-search-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.