xcode_build · Xcode MCP: Risk & Policy

WHAT IT DOES

What xcode_build does on Xcode

AI agents invoke xcode_build to trigger actions in Xcode. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why xcode_build needs a policy

Building is an Execute category action: it runs code (compilation, linking, build scripts, run phases) and triggers external operations. While the build process itself is typically deterministic for a given codebase, the build system can execute arbitrary scripts and has side effects (generates artifacts, modifies build directories, may trigger code generation).

From the tool's definition Tool description states it uses 'xcodebuild' to build the Xcode project. Building triggers compilation, linking, resource processing, and can execute build scripts and run phases—external operations whose effects depend on project configuration and arguments.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

xcode_build Rate-limited

xcode_build stays usable, but rate-capped — a runaway agent can't fire it dozens of times 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_build": {
      "limits": [
        {
          "counter": "xcode_build_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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_build

What does the xcode_build tool do? +

Build the Xcode project using xcodebuild. It is categorised as a Execute tool in the Xcode MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on xcode_build? +

Register the Xcode MCP server in PolicyLayer and add a rule for xcode_build: 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_build? +

xcode_build is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit xcode_build? +

Yes. Add a rate_limit block to the xcode_build 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_build completely? +

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

xcode_build 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.