deepseek-harness/packages/client/runtime/README.md

@deepseek-ai/dsh-client-runtime

Client cordis boot + core services: SlotsService (Service wrapper over SlotCore + 'slots/changed' bridge), SessionsService (list store projection, scope tree, bindings, ancestry), the Session object layer (exported as a type; instances are owned and handed out by SessionsService — the manager/paging internals stay package-internal, tests reach them via src), ClientLoader (./loader subpath, statically held by the shell). Contract: api-contracts v3 §4.

Session title projection

SessionManager retains the latest validated session/title control snapshot independently of list and session-instance arrival. Newer event seqs replace older snapshots, title timestamps contribute to list recency, and a subscription baseline discards any retained title beyond its lastSeq before the optional folded title arrives. Explicit session removal also clears the retained title. The client-facing SessionSummary.title is therefore only the actual durable title; displayTitle is always present and falls back through the cwd basename and session id. A cold persisted session keeps that fallback until opening or resuming it causes the host to fold and project its log-backed title.

Session model selection

Each resident Session owns a modelSelection snapshot containing the current provider/model target, provider-grouped directory, provider-local failures, and the idle/loading/ready/selecting/error state. History establishes or refreshes the current target, opening a selector refreshes the directory, and selection failures preserve the last target and usable groups. Directory and selection operations share a monotonically increasing generation so an older response cannot overwrite a newer selection. A reconnect rebuild restores the target reported by the Host without replacing unchanged selection substructure.

Model Experience

None, as the session object layer selects the provider/model route used by a later Host request but adds no model-visible content.

KV Cache effect

Changing the target can change or invalidate provider-side cache reuse; this package does not alter the prompt prefix itself.

Known Limitations and Deferred Work

• loader.unload is a stub (throws not-implemented) — the full chain (fiber dispose → registration cascade → style removal) lands with the HMR project.
• Scope teardown is stage-driven, single-occupant today — the staged session follows list.current exactly (staging is the open signal: the event window opens ⟺ the session is on stage); a removed-while-staged session's scope survives frozen until the stage moves on, not until true observer count reaches zero. Resolution (cell()/binding()/scope()) is pure addressing, render-safe. The staged state can widen to a multi-pane list when concurrent panes land.
• Value imports of this package from plugin bundles must use the /client subpath — the bare package name is not in the loader externals table and inlines a second module instance, whose private scope-tag Symbol never matches (the empty-state P0 postmortem).