file_extension · FreeTaxUSA MCP Server MCP: Risk & Policy

WHAT IT DOES

What file_extension does on FreeTaxUSA MCP Server

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

WHY IT NEEDS A POLICY

Why file_extension needs a policy

This tool creates/modifies tax filing records by submitting an extension form to the IRS. While the word 'File' might suggest Destructive intent, the core action is creating a new document/record rather than irreversibly destroying data. The severity is high because unauthorized extension filings could delay refunds, trigger penalties if misapplied, or cause compliance issues.

From the tool's definition Tool is described as 'File Form 4868 for an automatic extension.' Form 4868 is an IRS tax extension form that, when filed, creates a new legal tax obligation record.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

file_extension Rate-limited

file_extension 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_extension": {
      "limits": [
        {
          "counter": "file_extension_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 FreeTaxUSA MCP Server, so you can run agents against it safely.

FAQ

Questions about file_extension

What does the file_extension tool do? +

[Phase 3 - Not yet implemented] File Form 4868 for an automatic extension. It is categorised as a Write tool in the FreeTaxUSA MCP Server 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_extension? +

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

What risk level is file_extension? +

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

Can I rate-limit file_extension? +

Yes. Add a rate_limit block to the file_extension 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_extension completely? +

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

file_extension is provided by the FreeTaxUSA MCP Server MCP server (schwarztim/freetaxusa-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.