add_types_to_file · MCP Pyrefly Autotype Server MCP

WHAT IT DOES

What add_types_to_file does on MCP Pyrefly Autotype Server

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

WHY IT NEEDS A POLICY

Why add_types_to_file needs a policy

This tool creates or modifies data (Python source code) in a reversible manner. While it changes files, the modifications are non-destructive type annotations that preserve functionality and can be reverted or re-edited. This is characteristic of Write operations rather than Execute (which runs code with side effects) or Destructive (which cannot be undone).

From the tool's definition The tool 'add_types_to_file' modifies Python files by adding type annotations. The description states it will 'Add type annotations to a Python file', which constitutes modifying existing code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_types_to_file Rate-limited

add_types_to_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": {
    "add_types_to_file": {
      "limits": [
        {
          "counter": "add_types_to_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 MCP Pyrefly Autotype Server, so you can run agents against it safely.

FAQ

Questions about add_types_to_file

What does the add_types_to_file tool do? +

Add type annotations to a Python file using Pyrefly. It is categorised as a Write tool in the MCP Pyrefly Autotype 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 add_types_to_file? +

Register the MCP Pyrefly Autotype Server MCP server in PolicyLayer and add a rule for add_types_to_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 MCP Pyrefly Autotype Server. Nothing to install.

What risk level is add_types_to_file? +

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

Can I rate-limit add_types_to_file? +

Yes. Add a rate_limit block to the add_types_to_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 add_types_to_file completely? +

Set action: deny in the PolicyLayer policy for add_types_to_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 add_types_to_file? +

add_types_to_file is provided by the MCP Pyrefly Autotype Server MCP server (lolpack/mcp-pyrefly-autotype). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.