A Reddit user on the r/MacOSBeta subreddit discovered a "hidden lightweight UI" for Siri AI in the macOS 27 Golden Gate beta. This feature provides a pop-up menu of AI tools when text is highlighted, including Rewrite, Proofread, "How does this sound?," "Edit with Siri," summarization, and bullet points. Context-specific tools appear for phone numbers ("Add to contacts") and addresses ("Open in Maps"), along with tools for calendar events, messages, emails, and tracking flights and packages. According to MacRumors, the interface in macOS 27 developer beta 3 and public beta 1 is unfinished, with some features not working. Reddit user pdfu provided Terminal code to enable the interface: `sudo mkdir -p /Library/Preferences/FeatureFlags/Domain && sudo defaults write /Library/Preferences/FeatureFlags/Domain/WritingTools LightweightUI_macOS -dict Enabled -bool true`, followed by a restart. To disable it, users input `sudo defaults write /Library/Preferences/FeatureFlags/Domain/WritingTools LightweightUI_macOS -dict Enabled -bool false`. It is unclear if the interface will launch with the official macOS version.