xcode_set_build_setting · Xcode MCP: Risk & Policy

WHAT IT DOES

What xcode_set_build_setting does on Xcode

AI agents use xcode_set_build_setting 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_set_build_setting needs a policy

This tool modifies project configuration by changing build settings. While reversible (settings can be changed back), it affects how code is compiled and linked. Misuse could inject unsafe compiler flags, disable security checks (e.g., code signing, ASLR, stack canaries), or redirect build artifacts maliciously.

From the tool's definition Tool name is 'xcode_set_build_setting' and description states it 'Set a build setting in the Xcode project for a target and configuration'. Setting/modifying build settings is reversible data modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

xcode_set_build_setting Rate-limited

xcode_set_build_setting 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_set_build_setting": {
      "limits": [
        {
          "counter": "xcode_set_build_setting_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_set_build_setting

What does the xcode_set_build_setting tool do? +

Set a build setting in the Xcode project for a target and configuration. 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_set_build_setting? +

Register the Xcode MCP server in PolicyLayer and add a rule for xcode_set_build_setting: 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_set_build_setting? +

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

Can I rate-limit xcode_set_build_setting? +

Yes. Add a rate_limit block to the xcode_set_build_setting 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_set_build_setting completely? +

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

xcode_set_build_setting 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.