Tianyi Cui
25dcd7293c
Delete design-session citations (decision/audit/plan ordinals, stack positions), change narration, review choreography, and reviewer-addressed justification from comments, JSDoc, docs, READMEs, Agent Notes, tests, and generator templates; restate every affected fact as current-state contract prose. Fix generated docs at their sources and regenerate the catalogs and cordis-surface regions; re-paste type-equiv blocks; update every bilingual counterpart and re-record the pairs. Record the citation rule in the committed-artifact-citations Agent Note.
1.9 KiB
Agent Note: Event-sourced sessions with derived message history
Status: implemented
English | 中文
Problem
The MVP requires strict event-based tracing with fully replayable sessions (严格的基于事件的trace、logging系统，session完全可回放).
Decision
A Session is an append-only log of typed SessionEvents — the single source of truth. The LLM message history is derived from the log (deriveMessages()); raw stream chunks are logged for token-level replay fidelity while the assembled assistant/message event is authoritative for derivation. Replay/fork = seed a new session with an existing log.
Appends are synchronous (the hot path never blocks on I/O); session/event is a sync notification; persistence plugins buffer write-behind and drain at the awaited session/flush checkpoint fired at every turn end.
Ordering contract: the loop claims inbox messages before agent/pre-step, opens step/start only after an enter decision, then appends the returned user/message batch before request derivation. Provider output is assembled and appended as assistant/message before tool dispatch, so the durable log records the exact message the tools follow. Regression tests pin that ordering.
Alternatives considered
A mutable message array with events fired as notifications — simpler, but state and log can diverge; with event-sourcing the log IS the state, so divergence is structurally impossible.
Consequences
- Replay, trace, and telemetry are structurally guaranteed, not bolted on.
- Persistence stays a plugin concern; the in-memory store ships in dsh-session.
- The event vocabulary is merge-extensible (plugins add e.g. compaction events); session persistence froze its shape once the log became durable.
- Derivation cost grows with log length — compaction (dsh-compact) is the intended mitigation, not log mutation.