download_file · Markdown For Agents MCP: Risk & Policy

WHAT IT DOES

What download_file does on Markdown For Agents

AI agents use download_file to create or update resources in Markdown For Agents — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Markdown For Agents environment.

WHY IT NEEDS A POLICY

Why download_file needs a policy

This tool fetches a remote file and writes it to the local filesystem. It creates/overwrites a local file, which is a Write action. The severity is medium because it can write arbitrary binary content (including ZIPs or executables) to a local path, but it does not execute code or irreversibly destroy existing data by itself.

From the tool's definition Download a binary file (PDF, image, ZIP, etc.) from a URL and save it to a local path.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

download_file Rate-limited

download_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": {
    "download_file": {
      "limits": [
        {
          "counter": "download_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 Markdown For Agents, so you can run agents against it safely.

FAQ

Questions about download_file

What does the download_file tool do? +

Download a binary file (PDF, image, ZIP, etc.) from a URL and save it to a local path. It is categorised as a Write tool in the Markdown For Agents MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on download_file? +

Register the Markdown For Agents MCP server in PolicyLayer and add a rule for download_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 Markdown For Agents. Nothing to install.

What risk level is download_file? +

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

Can I rate-limit download_file? +

Yes. Add a rate_limit block to the download_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 download_file completely? +

Set action: deny in the PolicyLayer policy for download_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 download_file? +

download_file is provided by the Markdown For Agents MCP server (johnnyfoulds/markdown-for-agents-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.