xcode_write_file · Xcode MCP: Risk & Policy

WHAT IT DOES

What xcode_write_file does on Xcode

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

WHY IT NEEDS A POLICY

Why xcode_write_file needs a policy

This tool creates or modifies source code files reversibly. While it could theoretically be used to inject malicious code into a project, the action itself is reversible (code can be edited or reverted), making it Write rather than Execute or Destructive.

From the tool's definition Tool name 'xcode_write_file' and description 'Write content to a Swift/ObjC file in the project' explicitly indicate creation/modification of source code files.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

xcode_write_file Rate-limited

xcode_write_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": {
    "xcode_write_file": {
      "limits": [
        {
          "counter": "xcode_write_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 Xcode, so you can run agents against it safely.

FAQ

Questions about xcode_write_file

What does the xcode_write_file tool do? +

Write content to a Swift/ObjC file in the project. It is categorised as a Write tool in the Xcode MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on xcode_write_file? +

Register the Xcode MCP server in PolicyLayer and add a rule for xcode_write_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 Xcode. Nothing to install.

What risk level is xcode_write_file? +

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

Can I rate-limit xcode_write_file? +

Yes. Add a rate_limit block to the xcode_write_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 xcode_write_file completely? +

Set action: deny in the PolicyLayer policy for xcode_write_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 xcode_write_file? +

xcode_write_file is provided by the Xcode MCP server (raunaksplanet/xcode-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.