fs_backup_file · LocalAnt MCP: Risk & Policy

WHAT IT DOES

What fs_backup_file does on LocalAnt

AI agents use fs_backup_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_backup_file needs a policy

This tool creates (writes) a duplicate of file data. It is reversible (the backup can be deleted), causes no data loss, and has minimal blast radius if misused—an agent might create redundant backup copies but cannot destroy data or execute arbitrary code. It does not meet the threshold for Execute (no command execution) or Destructive (no irreversible deletion).

From the tool's definition Tool named 'fs_backup_file' with description 'Create a backup of a file' — it creates a new copy of existing data without modifying or deleting the original.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fs_backup_file Rate-limited

fs_backup_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_backup_file": {
      "limits": [
        {
          "counter": "fs_backup_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 LocalAnt, so you can run agents against it safely.

FAQ

Questions about fs_backup_file

What does the fs_backup_file tool do? +

Create a backup of a file. 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_backup_file? +

Register the LocalAnt MCP server in PolicyLayer and add a rule for fs_backup_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_backup_file? +

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

Can I rate-limit fs_backup_file? +

Yes. Add a rate_limit block to the fs_backup_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_backup_file completely? +

Set action: deny in the PolicyLayer policy for fs_backup_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_backup_file? +

fs_backup_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.