The For You feed was chronological, hashtag-interest-EXCLUSIVE, and ignored
follows entirely (docs/feed-algo-audit.md). Now it is inclusive + ranked:
- createForYouScorerStage scores each video: follows-boost (author you follow)
+ interest/watch-topic affinity (cosine vs your interests+watch-history vector)
+ freshness - disinterest penalty. Reuses Explore's vector/similarity helpers.
- createForYouScoreSorter ranks by that score (muted last, recency tiebreak).
- For You pipeline: interests now BOOST not exclude (enforceInterests:false);
scorer added; chronological sorter replaced. Never empty (falls back to
recency when you have no follows/interests/history).
- buildForYouFeedRuntime now feeds subscriptionAuthors + watchHistoryTagCounts.
Watched/blocked/muted are still removed (suppression/blacklist/moderation
stages unchanged). Cheat-resistant tests (older boosted items only win via the
boost). Grid renders end-to-end (~1.3s). Weight tuning is a follow-up.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
Traced registerForYouFeed/buildForYouFeedRuntime + feedEngine. Confirms hashtag
prefs, blocks, watch-history suppression, and moderation DO drive For You. Gaps:
G1 follows have zero effect on For You; G2 chronological not relevance-ranked;
G3 interest filter is binary/exclusive; G4 watch-topic affinity unused; G5 no
blending. No code changed.
