memos/apps/memos-local-plugin/core/episode

core/episode/

Episode lifecycle + stitching (V7 §2.4.1, §2.6 Tier 2b).

Why this directory is intentionally empty

V7 splits episode-related work across two responsibilities, and each already has its own module:

Concern	Lives in
Lifecycle (open / close / reopen)	core/session/episode-manager.ts
V7 §0.1 relation classifier	core/session/relation-classifier.ts
Persistence adapter	core/session/persistence.ts (EpisodesRepo)
SQL schema	core/storage/migrations/001-initial.sql
Tier 2b "episode replay"	core/retrieval/tier2-trace.ts::rollupEpisodes
Event aggregation	core/session/events.ts

Episode logic is intimate with session logic (same lifecycle bus, same repo transactions), so folding it into core/session/ avoids a circular dependency between core/episode/ and core/session/. The architecture diagram in ARCHITECTURE.md §3.2 lists this directory for discoverability only — actual code belongs next to the session manager.

Episode stitching in practice

V7 §2.4.1 calls out "episode stitching" as auxiliary — not a prerequisite for L2 induction. We implement it implicitly:

1. EpisodeManager.start opens a row in episodes.
2. pipeline/orchestrator.ts::onTurnStart classifies the incoming user turn's relation to the previous episode (revision / follow_up / new_task) and either:
   • reopens the previous episode (revision, V7 §0.1),
   • starts a fresh episode in the same session (follow-up), or
   • starts a new session + episode (new task).
3. Capture attaches trace_ids to the episode on finalize.
4. Retrieval's Tier 2b reads all traces belonging to one episode and renders a chronological action-sequence summary when the episode's goal-level cosine clears episodeGoalMinSim — this is the "sub-task episode replay" V7 §2.6 Tier 2b describes.

Invariants

• An episode always belongs to exactly one session.
• episodes.status ∈ {'open', 'closed'}. Reopening a closed episode (V7 §0.1 revision path) flips status back to 'open' and records meta.reopenReason.
• Trace rows hold the authoritative episode_id foreign key; the episode's trace_ids_json is a denormalised convenience field (kept in sync by EpisodeManager.attachTraceIds).
• Episode lifecycle events are emitted on the SessionEventBus (episode.started, episode.turn_added, episode.finalized, episode.abandoned, episode.reopened, episode.relation_classified).

Tests

• tests/unit/session/episode-manager.test.ts — lifecycle.
• tests/unit/session/relation-classifier.test.ts — V7 §0.1 routing.
• tests/unit/retrieval/tier2.test.ts — Tier 2b rollup + goal filter.
• tests/unit/pipeline/memory-core.test.ts — end-to-end through the orchestrator (revision + new_task routing integration).