file_write · LuzzyTool MCP: Risk & Policy

WHAT IT DOES

What file_write does on LuzzyTool

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

WHY IT NEEDS A POLICY

Why file_write needs a policy

This tool creates or modifies file contents. While reversible (files can be edited or deleted by other means), it modifies local data and could corrupt or overwrite important files if misused by an AI agent. It is Write rather than Destructive because the operation is reversible and not inherently irreversible. High severity due to potential for data loss or system configuration corruption on a local system.

From the tool's definition Tool name 'file_write' and description '将内容写入本地文件' (write content to local file) explicitly indicates data modification capability. The description confirms it writes to files.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

file_write Rate-limited

file_write 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": {
    "file_write": {
      "limits": [
        {
          "counter": "file_write_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 LuzzyTool, so you can run agents against it safely.

FAQ

Questions about file_write

What does the file_write tool do? +

【必须调用】将内容写入本地文件。. It is categorised as a Write tool in the LuzzyTool MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on file_write? +

Register the LuzzyTool MCP server in PolicyLayer and add a rule for file_write: 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 LuzzyTool. Nothing to install.

What risk level is file_write? +

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

Can I rate-limit file_write? +

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

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

file_write is provided by the LuzzyTool MCP server (luzzymeow/luzzytool). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.