Apple users have been waiting for a long time for a significant improvement in the voice assistant Siri, which is offered on all of the manufacturer’s devices. With the update to System 27, the time has finally come: Siri is receiving an LLM-based makeover. This goes hand in hand with a redesign of the operating interface. There is no sign of this in the current beta versions – at least not at first glance. However, a Reddit user claims to have found a way to see at least some of the tools. Internally, the graphical controls are called “Lightweight UI”. In the final macOS 27 Golden Gate (and probably iOS/iPadOS 27 as well) they will be available whenever text is selected. When a user clicks on the Siri logo, contextual AI prompts appear that they can apply to the selection. They have already been created in the third developer beta, as well as in the first public beta. However, you first have to activate it using a terminal command and a restart.
Hidden marker
In order to use the lightweight Siri interface, you must create a file called “WritingTools” in the /Library/Preferences/FeatureFlags/Domain/ folder and provide it with the correct instructions. The easiest way to do this is to enter two terminal commands individually and confirm each with the Enter key:
sudo defaults write /Library/Preferences/FeatureFlags/Domain/WritingTools LightweightUI_macOS -dict Enabled -bool true
You then need to restart your Mac (or virtual machine). The new Siri symbol will then appear to the left of the selected text as soon as the mouse pointer hovers over the passage. Clicking on it reveals various subcommands. Some of these correspond to the text tools that have also been available to users in the EU since macOS 15.4. An additional, floating input field labeled “Ask Siri” also allows you to enter your own prompt.
Still very unfinished
There is a reason why this new operating option is not yet active by default: many of the commands shown do not yet respond to clicks. Nevertheless, experiments with the unfinished GUI can be worthwhile: they reveal how Apple imagines interaction with Siri in the future. It will be some time before “Siri AI”, as the new version is called, is available for German-speaking users – Apple is talking about a launch at a later date in 2026 and is initially limiting the function to the English language.
Disable Siri LightweightUI
If the still unstable Siri interface becomes a burden within your own beta installation, it can be switched off just as quickly. Using the command line command
sudo defaults write /Library/Preferences/FeatureFlags/Domain/WritingTools LightweightUI_macOS -dict Enabled -bool false
and a subsequent restart ensure that the Siri floating menu initially disappears again. If you want to activate it again later, all you have to do is run the second of the two command line commands listed above.
