fs_mkdir · E MCP: Risk & Policy

WHAT IT DOES

What fs_mkdir does on Emcp

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

WHY IT NEEDS A POLICY

Why fs_mkdir needs a policy

'mkdir' is a standard filesystem operation that creates a new directory. This is a reversible write operation (directories can be removed). The empty description lowers confidence slightly, but the name is unambiguous. Severity is medium because misuse could create unwanted directory structures, but it does not delete or overwrite existing data.

From the tool's definition Tool name 'fs_mkdir' strongly implies creating a directory on the filesystem. Description is empty, so classification is based on naming convention alone.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fs_mkdir Rate-limited

fs_mkdir 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": {
    "fs_mkdir": {
      "limits": [
        {
          "counter": "fs_mkdir_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about fs_mkdir

What does the fs_mkdir tool do? +

fs_mkdir. It is categorised as a Write tool in the Emcp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fs_mkdir? +

Register the E MCP server in PolicyLayer and add a rule for fs_mkdir: 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 Emcp. Nothing to install.

What risk level is fs_mkdir? +

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

Can I rate-limit fs_mkdir? +

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

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

fs_mkdir is provided by the E MCP server (slezica/emcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.