New titles on this watchlist

This is NOT the per-service mode above it, even though both get called "the watchlist mode". That one decides what Kustos writes to somebody's watchlist; this one decides what Kustos does with what it reads from it. The two are laid out side by side on Watchlists.

It is the only auto-add route — there is no second mechanism to keep in step.

• Ignore watchlist (the default) — Kustos ignores this watchlist.
• Ask me first — new titles land in Requests for you to approve.
• Add automatically — anything new they watchlist gets added on its own, straight to Sonarr/Radarr.

A public or free-typed Trakt profile isn't a Plex person, so it has no mode — but you can still bulk-add from it.