Mixer contract

Inputs

Input	Type	Source
liveBatch	TweetResult[]	API state + posts rehydrate
canonicalPool	TweetResult[]	tf_canonical_posts
seenPostIds	Set<string>	seen_items
churnSeed	number	Remix epoch + page salt (Home only)

Output

feedPosts — ordered list for the active tab after:

1. mergeFeedWithUnseenCanonicalFirst (Home) or mergeFeedById (other pages)

2. buildMixerFeedPostsBase — time window, Top/Latest/Media, topic prefs

Invariants

• Dedupe by tweet id across live and canonical.

• Unseen canonical precedes live on Home (unless include-seen).

• No persisted mixerCache in v1 — order is reproducible given same seed and DB snapshot.

UI surfaces

• Home: classic/stream TweetCard (not masonry tiles for main tabs).

• Spaces/Broadcasts directories may use tile layout (ix-feed--masonry).