AppleIntelligenceMediator fails on macOS 26.5.1 — Catalyst System Settings panes not accessible via AX API

[Michael-Z-Freeman]

Hi. When I first tested the agent with "Open display settings" access to the local AI model failed and agent dropped to the LLM. This appears to be to do with update to macOS 26.5.1.

Environment: macOS 26.5.1 (Sequoia)

Summary:
The AppleIntelligenceMediator fails because Catalyst System Settings panes on macOS 26.5.1 don't expose their inner UI controls (toggles, buttons) through the Accessibility API. Traditional AppKit-based AX traversal doesn't work here.

Evidence:

• Apple Intelligence & Siri is confirmed already enabled
• URL schemes (x-apple.systempreferences:com.apple.preference.appleintelligence) successfully open the pane
• But AX find_element for specific controls returns nothing — this is NOT a permissions issue, AX is properly granted

Four recommended fixes:

1. Env/config flag to skip the check — quickest path, user can set a flag to bypass the mediator
2. Read system plist keys directly — probe system defaults/plist instead of UI interaction (most robust)
3. System Events keyboard navigation workaround — fragile, depends on tab order
4. Better logging when AX fails — currently fails silently, hard to debug

Workaround:
Since Apple Intelligence is already enabled, a quick flag-based skip in the mediator would unblock downstream features immediately.

Appendix:
The old .appex Extensions directory pattern is obsolete in macOS 26.5.1 — the Settings pane registration has moved to a different mechanism, confirming the old assumptions in the codebase are stale.

[macOS26]

Will look into potential issues with Tahoe update 26.5.1. Try turning off Apple AI in the brain icon where Agent! / the main LLM has more tools at its disposal.