Reactions live in the existing messages.display_metadata JSON column (no new
table), with iOS Tapback semantics enforced DB-side: one reaction per author
per message, re-tap retracts, different emoji replaces. The desktop catches up
to the reaction contract five platform adapters already ship.
- SessionDB: set/get_message_reaction, latest_message_row_id (role + offset +
require_text so invisible tool-call-only rows are never targeted),
take_unseen_reactions (announce-exactly-once), get_message_role
- message.react RPC: accepts row_id or newest_role for live messages that
haven't learned their durable id yet
- react_to_message tool: desktop-gated (check_fn), defaults to the user's
latest visible message, messages_back for retroactive reactions
- Model context rides run_message only (beside the speech-interrupted note):
the persisted prompt stays clean, so no [The user reacted …] scaffolding in
transcripts, and no cached prefix ever changes
- Resume projection forwards row_id + reactions; _row_id is stripped from
outgoing API copies next to display_metadata
