Computer use: all synthetic clicks/keystrokes silently dropped on macOS; screenshots work, permissions verified good

Environment: Claude desktop app 1.20186.1, macOS 26.5.2 (M2 Pro Mac mini)

Symptom: In local agent mode, computer-use screenshots, cursor movement, and app-opening all work, but every synthetic click and keystroke is silently dropped — the tools report success ("Clicked." / "Key pressed."), yet nothing happens on screen.

Ruled out:

• Accessibility and Input Monitoring are granted; toggled off/on and verified fresh in the TCC database
• Claude app restarted after the permission reset
• Secure-input mode confirmed off
• Full macOS reboot performed

Still broken after all of the above.

Key evidence: AppleScript / System Events keystrokes sent from the same session deliver input successfully (a keystroke "n" using command down opened a new Finder window). So macOS is accepting synthetic input from the app's identity — only the computer-use event channel fails.

Repro:

1. Start a local agent mode session with computer use
2. request_access for Finder → granted, tier "full"
3. Click the File menu, or double-click a desktop folder
4. Tool returns success; screen shows no effect (menu doesn't open, folder isn't selected/opened)

Cursor position reads back exactly at the requested coordinates, so coordinate mapping appears correct — the click event itself never lands.