docs: document package model experience

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Tianyi Cui
2026-07-12 02:12:36 +08:00
parent 3dca90261c
commit 027970043c
75 changed files with 561 additions and 5 deletions

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@@ -4,6 +4,12 @@ A SQLite durable session-persistence backend — a second `SessionPersistence` i
> **TODO:** this backend talks to `node:sqlite` directly. If a cordis database service (`cordis/db` / a `@cordisjs` SQL driver plugin) is adopted, route through that instead of holding a raw `DatabaseSync` here — the contract surface (`SessionPersistence`) would not change, only the storage driver.
## Model Experience
| Context surface | What the model sees | Token effect |
|---|---|---|
| Resumed conversation history | SQLite storage contributes no live prompt or schema. Loading restores the same surface history as JSONL and preserves prior headers for reconstruction; the new loop composes its current envelope. Interrupted rows are balanced with error tool results. Row metadata and raw chunks are not messages. | Zero live-request tokens. Resume restores retained history and pays the current envelope, with small repair-result tokens only for an interrupted tool turn. |
## Storage model
Each `SessionEvent` maps 1:1 onto a row in an `events` table `(session_id, seq, type, time, data, source_event_seqs, surface_op)``data` is the event payload as JSON text, so the row shape is the event verbatim (including `assistant/chunk`, keeping `seq` contiguous). The two `TEXT` columns `source_event_seqs` and `surface_op` are nullable; they store the event's optional surface-metadata fields (see [session surface](../../../docs/rfc/implemented/architecture/2026-06-18-session-surface.md)). Out-of-log metadata (`SessionHeader`) lives in a `sessions` row. A `sessions` row is written only by the first `append` — its existence is the lazy-materialization signal (`list` reports exactly the sessions that have a row), so no separate column is needed.