Keyword Notification Rules

Per-user, per-room custom keyword rules (beyond @mentions) checked on createMessage and delivered via Event Grid + Web Push.

Why not

Mention-based notifications already cover the core "ping me when relevant" need.
Custom rules add per-user DB state and per-message scanning cost for marginal gain.

Previous

Rejected — append-only store of previous message versions.

Next

Read receipts / unread badges

Rejected — full per-message unread tracking; mention-only counts remain allowed.