Since Android 13 the system shows a preview of whatever was just copied, at the bottom of the screen. For a password that is precisely what we are trying to avoid: it appears in clear, outside the app, for several seconds. The flag that suppresses it is a ClipDescription extra, which IFMXClipboardService does not expose - hence going straight to ClipboardManager. Note Jcontent_ClipboardManager, not JClipboardManager: the latter is the deprecated android.text one, which knows only bare text and has no ClipData to carry an extra.
Backgrounding already locks; the idle timer covers the phone left face-up on a table with the app open. It samples timestamps every 15 s rather than counting seconds - a wake-up per second would cost battery for no precision that matters.
Attachments dropped from the plan: this vault has none.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>