Fix: Xcode Command PhaseScriptExecution Failed (Cursor)

Hitting Command PhaseScriptExecution failed with a nonzero exit code in Xcode after generating code with Cursor? The short answer: this is not your Swift code, it is a run-script build phase failing, and the causes are a short, fixable list. Read the real error in the build log, match it to a cause below, and apply the fix. Starting clean, for example building the UI from a free VP0 design and keeping a standard project layout, prevents most of these in the first place.

Who this is for

This is for people building iOS apps with Cursor and other AI tools who get a red build failure pointing at a script phase rather than a line of Swift, and want to know what actually broke.

Read the real error first

The red “Command PhaseScriptExecution failed with a nonzero exit code” line is a summary, not the cause. Open the build log, expand the failed Run Script phase, and read the message printed just above it. That line, “command not found,” “operation not permitted,” “pod: not found,” is the truth. The Apple guide to running custom scripts during a build explains how these phases work, and the Xcode build system documentation covers where to find the log. Never debug the summary line; debug the message above it.

Symptom in the log	Likely cause	Fix
sandbox or “operation not permitted”	Script sandboxing blocks file writes	Set ENABLE_USER_SCRIPT_SANDBOXING to No, or declare input and output files
”command not found” / node missing	Tool not on Xcode’s PATH	Use absolute paths or source the right environment in the script
”pod: not found”	CocoaPods not installed or wrong shell	Install pods, run pod install, open the .xcworkspace
”No such file or directory”	Missing input or output file list	Add the script’s input and output files
Expo or RN script fails	Stale node_modules or cache	Reinstall, clear Metro and derived data

The fixes that actually work

For sandboxing, the quick fix is setting ENABLE_USER_SCRIPT_SANDBOXING to No in build settings, but the clean fix is declaring the script’s input and output files so it runs inside the sandbox. For a missing tool, AI-generated scripts often assume node or a CLI is on the PATH, which Xcode does not inherit, so use absolute paths or explicitly source the environment. For CocoaPods, make sure pods are installed and you opened the .xcworkspace, not the .xcodeproj. After any fix, clean the build folder and clear derived data so you are not chasing a cached failure.

Build cleaner so it happens less

Most of these errors come from AI builders bolting on build phases that assume a setup you do not have. Keep the project standard: a conventional structure, scripts added deliberately with declared inputs and outputs, and dependencies installed before you build. Building the UI from a clean reference like a free VP0 design keeps the project predictable, so Xcode has fewer surprise phases to fail on. For related AI-build-error fixes, see the Xcode command phase script failed fix, an Expo EAS build failed with CocoaPods on AI-generated code, a Lovable export missing Info.plist in Xcode, and Cursor rules for a SwiftUI native mobile template. When you do ship, remember the Apple Developer Program is $99 a year, so get the build green well before submission.

Common mistakes

The first mistake is debugging the red summary line instead of the real error above it. The second is disabling sandboxing blindly when declaring files is the proper fix. The third is assuming Xcode inherits your terminal PATH; it does not. The fourth is opening the .xcodeproj when CocoaPods needs the .xcworkspace. The fifth is not clearing derived data, so you keep seeing a cached failure after you already fixed it.

Key takeaways

• The error is a build script failing, not your Swift code; read the message above the red line.
• From Cursor code the usual causes are sandboxing, a missing PATH tool, CocoaPods, or missing file lists.
• Fix the specific cause; for sandboxing, declaring input and output files beats disabling it.
• Clean the build folder and derived data after a fix to avoid chasing a cached error.
• Start from a clean reference like a free VP0 design so fewer surprise phases exist.

Sources

• Apple Xcode documentation: the official toolchain for building and signing iOS apps.
• React Native architecture overview: how React Native renders real native views.
• Metro bundler troubleshooting: fixing the React Native JavaScript bundler.

Frequently asked questions

What does Command PhaseScriptExecution failed mean in Xcode? A run-script build phase exited with a nonzero code, so the failure is in a script, not your Swift. Read the actual error above the red summary line.

Why do I get this error from Cursor AI generated code? AI builders add or assume build scripts without the matching setup. Common causes are sandboxing, a missing PATH tool like node, or missing file lists.

How do I fix script sandboxing errors in Xcode? Set ENABLE_USER_SCRIPT_SANDBOXING to No, or better, declare the script’s input and output files so it works within the sandbox.

How do I avoid these build errors in the first place? Start from a clean, known-good project, add scripts deliberately, and build the UI from a free VP0 design so the structure stays standard.