diff --git a/docs/rfc/implemented/2026-06-18-session-surface.md b/docs/rfc/implemented/2026-06-18-session-surface.md index 159db911b1..528718b968 100644 --- a/docs/rfc/implemented/2026-06-18-session-surface.md +++ b/docs/rfc/implemented/2026-06-18-session-surface.md @@ -1,10 +1,10 @@ -# ADR 0019: Session surface — a linked list over the event log for LLM message derivation +# RFC: Session surface — a linked list over the event log for LLM message derivation -Status: accepted (2026-06-17) +Status: implemented (accepted 2026-06-18) ## Context -The `Session` event log is the single source of truth ([ADR 0003](0003-event-sourced-sessions.md)), but the only view over it was `deriveMessages()` — a linear scan that filtered and transformed raw events into `Message[]`. This creates problems for session-history-manipulating plugins (compaction, tool-call result pruning, etc.). Without a central mechanism, each plugin would need to wrap `agent/request` to rewrite the message list — a pattern that suffers from listener-ordering fragility, provides no durable record of what was changed, and forces repeated changes to the core `deriveMessages()` whenever a new manipulation is added. A central hub in the `session` package, with a provenance-recording mechanism and enough flexibility for future plugins to manipulate session history through a stable API, lays a solid foundation for plugin development. +The `Session` event log is the single source of truth ([event-sourced sessions](../implemented/2026-06-11-event-sourced-sessions.md)), but the only view over it was `deriveMessages()` — a linear scan that filtered and transformed raw events into `Message[]`. This creates problems for session-history-manipulating plugins (compaction, tool-call result pruning, etc.). Without a central mechanism, each plugin would need to wrap `agent/request` to rewrite the message list — a pattern that suffers from listener-ordering fragility, provides no durable record of what was changed, and forces repeated changes to the core `deriveMessages()` whenever a new manipulation is added. A central hub in the `session` package, with a provenance-recording mechanism and enough flexibility for future plugins to manipulate session history through a stable API, lays a solid foundation for plugin development. ## Decision diff --git a/packages/session-persistence-sqlite/README.md b/packages/session-persistence-sqlite/README.md index cec1e9700f..6eb8568e46 100644 --- a/packages/session-persistence-sqlite/README.md +++ b/packages/session-persistence-sqlite/README.md @@ -6,7 +6,7 @@ A SQLite durable session-persistence backend — a second `SessionPersistence` i ## 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 [ADR 0019](../../docs/adr/0019-session-surface.md)). The schema migrates from v1 to v2 via `ALTER TABLE ADD COLUMN` — existing rows get NULL for both columns, which is correct for events written before surface support. Out-of-log metadata (`SessionMeta`) lives in a `sessions` row, including the mutable `SessionSummary` fields (`updatedAt`, `title`, `firstPrompt`) that `update()` rewrites without touching the event log. A `sessions` row is written only by the first `append` — its existence is the lazy-materialization signal (`has`/`list` report exactly the sessions that have a row), so no separate column is needed. +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/2026-06-18-session-surface.md)). The schema migrates from v1 to v2 via `ALTER TABLE ADD COLUMN` — existing rows get NULL for both columns, which is correct for events written before surface support. Out-of-log metadata (`SessionMeta`) lives in a `sessions` row, including the mutable `SessionSummary` fields (`updatedAt`, `title`, `firstPrompt`) that `update()` rewrites without touching the event log. A `sessions` row is written only by the first `append` — its existence is the lazy-materialization signal (`has`/`list` report exactly the sessions that have a row), so no separate column is needed. The repo targets Node ≥ 24 (the root `engines` field), which includes the stable `node:sqlite` module. The database opens with `foreign_keys = ON` (so `ON DELETE CASCADE` drops a session's events with its row) and `journal_mode = WAL`. The table-layout version is stored in `PRAGMA user_version` and checked on open: a fresh database is stamped with the current `SCHEMA_VERSION`; a database written by a newer, incompatible build (higher `user_version`) is rejected rather than opened against an unknown layout.