fs_move_file · LocalAnt MCP: Risk & Policy

WHAT IT DOES

What fs_move_file does on LocalAnt

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

WHY IT NEEDS A POLICY

Why fs_move_file needs a policy

Moving or renaming files modifies the filesystem state reversibly—the operation can be undone by moving the file back or restoring from backup. This is a Write operation rather than Destructive because the data itself is not deleted or overwritten, merely relocated.

From the tool's definition Tool name 'fs_move_file' and description 'Move/rename a file within the allowlist' indicate file modification operations that are reversible.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fs_move_file Rate-limited

fs_move_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": {
    "fs_move_file": {
      "limits": [
        {
          "counter": "fs_move_file_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 LocalAnt, so you can run agents against it safely.

FAQ

Questions about fs_move_file

What does the fs_move_file tool do? +

Move/rename a file within the allowlist. It is categorised as a Write tool in the LocalAnt 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_move_file? +

Register the LocalAnt MCP server in PolicyLayer and add a rule for fs_move_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 LocalAnt. Nothing to install.

What risk level is fs_move_file? +

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

Can I rate-limit fs_move_file? +

Yes. Add a rate_limit block to the fs_move_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 fs_move_file completely? +

Set action: deny in the PolicyLayer policy for fs_move_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 fs_move_file? +

fs_move_file is provided by the LocalAnt MCP server (yuga-hashimoto/localant). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.