diff --git a/crates/arr-core/src/lib.rs b/crates/arr-core/src/lib.rs
index 3449d2d..11f2517 100644
--- a/crates/arr-core/src/lib.rs
+++ b/crates/arr-core/src/lib.rs
@@ -7,6 +7,7 @@ use std::{collections::BTreeMap, path::PathBuf, time::SystemTime};
 pub mod lang;
 pub mod policy;
 pub mod score;
+pub mod tracking;
 
 pub use arr_parse::NameClaims as ParsedRelease;
 pub use score::{Score, ScoreWeights};
diff --git a/crates/arr-core/src/tracking.rs b/crates/arr-core/src/tracking.rs
new file mode 100644
index 0000000..8aa56ab
--- /dev/null
+++ b/crates/arr-core/src/tracking.rs
@@ -0,0 +1,86 @@
+use crate::{Episode, Series};
+
+/// Applies a series' tracking rule to episodes discovered in a new season.
+///
+/// Callers pass only episodes from a newly revealed season. Existing seasons
+/// keep their leaf-level intent unchanged.
+pub fn apply_new_season_auto_track(series: &Series, episodes: &mut [Episode]) {
+    if series.auto_track {
+        for episode in episodes {
+            episode.wanted = true;
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::time::SystemTime;
+
+    use super::apply_new_season_auto_track;
+    use crate::{
+        Episode, EpisodeId, Language, MediaState, RootId, SeasonId, Series, SeriesId,
+        TitleOverrides,
+    };
+
+    fn series(auto_track: bool) -> Series {
+        Series {
+            id: SeriesId(1),
+            tmdb_id: 82_728,
+            title: "Bluey".into(),
+            year: 2018,
+            original_language: Language::Other("en".into()),
+            root_id: RootId(1),
+            auto_track,
+            overrides: TitleOverrides::default(),
+            upstream_ended: false,
+            blocked: false,
+        }
+    }
+
+    fn episode(season: i64, number: u16, wanted: bool) -> Episode {
+        Episode {
+            id: EpisodeId(season * 100 + i64::from(number)),
+            season_id: SeasonId(season),
+            number,
+            title: format!("Episode {number}"),
+            air_date: Some(SystemTime::UNIX_EPOCH),
+            wanted,
+            state: MediaState::Missing,
+            search_attempts: 0,
+            last_searched_at: None,
+        }
+    }
+
+    #[test]
+    fn auto_track_marks_new_season_episodes_wanted() {
+        let mut new_season = vec![episode(3, 1, false), episode(3, 2, false)];
+
+        apply_new_season_auto_track(&series(true), &mut new_season);
+
+        assert!(new_season.iter().all(|episode| episode.wanted));
+    }
+
+    #[test]
+    fn untracked_series_keeps_leaf_intent_only() {
+        let manually_wanted_season = [
+            episode(2, 1, true),
+            episode(2, 2, true),
+            episode(2, 3, true),
+        ];
+        let mut new_season = vec![episode(3, 1, false), episode(3, 2, false)];
+
+        apply_new_season_auto_track(&series(false), &mut new_season);
+
+        assert!(manually_wanted_season.iter().all(|episode| episode.wanted));
+        assert!(new_season.iter().all(|episode| !episode.wanted));
+    }
+
+    #[test]
+    fn auto_track_does_not_clear_explicit_leaf_intent() {
+        let mut new_season = vec![episode(3, 1, true), episode(3, 2, false)];
+
+        apply_new_season_auto_track(&series(true), &mut new_season);
+
+        assert!(new_season.iter().all(|episode| episode.wanted));
+    }
+}