Recently I needed to develop my own Xcode source editor extension. The reasons for doing so aren’t relevant here, but the process quickly led me into an unexpected roadblock.
TL;DR: In your extension target settings, set XcodeKit.framework → “Embed without signing” under the General tab.
Extension not showing up in Xcode
After following Apple’s official guide for creating a source editor extension (a macOS app with an extension target), I ran the extension scheme to test it. However, the extension neither appeared in Xcode nor executed any code.
Normally, a source editor extension should appear in two places:
- macOS System Settings (Extensions → Xcode Source Editor)
- Xcode’s Editor menu
In my case, the extension showed up in System Settings but did not appear in Xcode.
Asking around
Like most developers, I immediately turned to Google and AI tools. It quickly became clear that this issue is not uncommon. Unfortunately, none of the suggested workarounds solved my problem.
Sifting through Xcode logs
After exhausting the usual fixes, I wondered whether Xcode might be logging something useful while attempting to load extensions.
Using the unified logging system, I started streaming Xcode logs with a predicate to filter relevant messages:
log stream --style compact --predicate 'process == "Xcode" && (eventMessage CONTAINS[c] "EditorExtension" || eventMessage CONTAINS[c] "XcodeKit")'
After running the extension again, I noticed the following message:
Xcode Extension does not incorporate XcodeKit
This was finally a clue.
Looking at existing extensions
My next step was to inspect existing open-source extensions. I looked at projects like SwiftFormat and compared their release artifacts with the one produced by my own extension.
Missing XcodeKit.framework
While inspecting the extension bundle, one difference stood out immediately: my extension was not bundling XcodeKit.framework, while SwiftFormat’s extension was.
I also noticed that SwiftFormat’s release workflow explicitly ensures that XcodeKit.framework is bundled into the extension archive.
The fix: Embed without signing
It turns out the default Xcode template for source editor extensions is misconfigured.
By default, XcodeKit.framework is set to “Do Not Embed” in the extension target settings. Because of this, the framework never gets bundled with the extension.
Changing the setting to:
General → Frameworks, and Libraries → XcodeKit.framework → “Embed without signing”
fixes the issue and allows Xcode to load the extension correctly.
Closing thoughts
Problems like this are especially frustrating when there’s little to no documentation online and even AI tools can’t identify the cause.
One useful takeaway is that Apple heavily relies on the Unified Logging System across their apps, tools and macOS in general. When something misbehaves, inspecting logs can provide a path forward.