deepseek-harness/packages/session-query/session-query

@deepseek-ai/dsh-session-query

Exact session-history retrieval and relationship tracing through ctx.sessionQuery. The service presents live ctx.sessions and an optional, dynamically mounted ctx.sessionPersistence as one logical corpus. Matching ids produce one record: live events win, while live and persisted report both source availabilities. Conflicting immutable headers fail with SESSION_QUERY_SOURCE_CONFLICT.

Reads

• listSessions() reads current persistence metadata, merges live records with live precedence, and returns cloned records in deterministic newest-first order.
• readTitle(sessionId) loads one live-preferred or persisted log and folds its latest session/title event into a SessionTitleSnapshot; it returns undefined when the known session has no title.
• listEvents(sessionId) loads the live-preferred raw log and classifies each event as current, shadowed, or log-only with the shared dsh-session surface fold.
• readSurface(sessionId) returns one cloned header, raw-log capture boundary, and the complete folded current surface in model-history order. A live session wins over persistence; compaction is observed before or after its replacement append, never as a synthetic mixture.
• readEvent(request) returns a cloned header, the full target event, and a bounded raw-seq window. before and after default to zero and may not exceed readWindowMax.
• traceSession(sessionId) reads the corpus once and returns immediate-to-outward ancestors plus deterministic recursive descendant trees. complete: false identifies the first missing parent; a target-connected cycle fails with SESSION_QUERY_INVALID_LINEAGE.
• traceEvent(request) loads the logical log once and returns direct positional replacements and direct logged provenance. replacementChain follows positional replacers to the final replacement; provenance links remain non-transitive.

Persistence is optional and may mount or unmount dynamically. Cross-corpus listing and lineage tracing fail with SESSION_QUERY_PERSISTENCE_FAILED while mounted persistence is unreadable. A title, event read, or trace targeting a known live session does not consult persistence, so durable backend health cannot make current in-memory state unreadable. Persisted title and event operations list before loading and reject a metadata mismatch rather than combining inconsistent observations. listSessions() remains lightweight and does not load logs or index titles.

listEvents(), readSurface(), and traceEvent() run the same one-pass dsh-session surface fold. A loaded log is valid only when event seqs are zero-based and contiguous, surface markers obey event-type eligibility, provenance arrays are nonempty and duplicate-free, references name earlier events, and each positional replacement names and cites every surface node it removes; every violation fails with SESSION_QUERY_INVALID_SURFACE.

SessionQueryError.code is a closed union: SESSION_QUERY_EVENT_NOT_FOUND, SESSION_QUERY_INVALID_CONFIG, SESSION_QUERY_INVALID_LINEAGE, SESSION_QUERY_INVALID_SURFACE, SESSION_QUERY_INVALID_WINDOW, SESSION_QUERY_PERSISTENCE_FAILED, SESSION_QUERY_SESSION_NOT_FOUND, and SESSION_QUERY_SOURCE_CONFLICT.

Configuration

Key	Default	Contract
readWindowMax	50	Maximum before or after raw-event count.

Model Experience

None, as this trusted query service returns cloned session records only to its callers and registers no model-facing prompt, schema, tool, or message.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

• No caller authorization — this is trusted context-wide infrastructure; a future model tool or UI must constrain which sessions its caller may inspect.
• No search or extraction — filters, extraction registry, search-provider protocol, index synchronization, and a model-facing tool are absent. The tracing decision owns relationship semantics; content-bearing full-text-search results and their chainable filters belong beside their first implementation in the proposed SQLite package.