curl_download · Curl MCP Server MCP: Risk & Policy

WHAT IT DOES

What curl_download does on Curl MCP Server

AI agents invoke curl_download to trigger actions in Curl MCP Server. 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 curl_download needs a policy

This tool runs a curl command that downloads a file to the local filesystem. While it may appear to be a Read operation, saving files to disk is a side-effecting Write/Execute action. Since it executes an external curl process with configurable parameters (inherited from server description), it falls under Execute.

From the tool's definition 'Download a file using curl' — executes a curl command to fetch and write a file to the filesystem; 'return metadata' suggests the file is actually saved locally

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

curl_download Rate-limited

curl_download 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": {
    "curl_download": {
      "limits": [
        {
          "counter": "curl_download_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 Curl MCP Server, so you can run agents against it safely.

FAQ

Questions about curl_download

What does the curl_download tool do? +

Download a file using curl and return metadata. It is categorised as a Execute tool in the Curl MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on curl_download? +

Register the Curl MCP Server MCP server in PolicyLayer and add a rule for curl_download: 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 Curl MCP Server. Nothing to install.

What risk level is curl_download? +

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

Can I rate-limit curl_download? +

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

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

curl_download is provided by the Curl MCP Server MCP server (neeraj15022001/curl-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.