@deepseek-ai/dsh-api-session-controller owns the Host ctx.sessionController service and the generated Client session, skills, and fileReferences Remote namespaces. It serves Session lifecycle and history, the Host-generation model catalog, workspace-path opening, user-invocable skill discovery, and the adapter for Agent-scoped file references. Use it through API Gateway when a Client needs operations addressed by a Session.

Use this package
Configuration
Model Experience
Known Limitations and Deferred Work
Dev Note

Use this package

History pages and follow opening snapshots carry one { type: 'event', event: SessionWireEvent } record per durable Session event. The Client retains each accepted record as one durable SessionEventLikeEntry; Assistant token boundaries remain inside the compact stream on assistant/message or assistant/attempt. Tool arguments, result content, failures, and tool/result.data.meta pass through unchanged; the controller does not resolve a Tool definition, run a presenter, or attach UI data.

Each endpoint states its activation policy. List, search, attachment, history pages, log following, skill discovery, and workspace-path opening can inspect persistence without activating an Agent; canOpenWorkspacePath() reports native-opening availability without addressing a Session. Queue mutation and cancellation require live state; model, rename, prompt, and file-reference operations may resolve or resume an ordinary Session. Create and fork are the only operations that create a new Agent directly. The skill catalog instead uses a live Agent when present or the recorded preset's standing scope when cold, so listing never starts an Agent.

The Client adapter exposes SessionEventStream, a Gateway RemoteJournalStream bound to one ordinary or direct-subagent address. It opens follow before the initial page, publishes only contiguous replace, prepend, and append changes, and repairs reconnect or sequence gaps through a tail page. Backwards paging has two verbs: loadOlder() pulls one 50-message page, and loadThrough(seq) — the turn-jump loader — loops 200-message pages until the window covers the target seq, lowering a shared target on repeated calls, stopping on a page that makes no progress, and reporting busy through the same loadingOlder snapshot bit. The Web adapter explicitly opts into cursorless Assistant frames: each opening carries the active attempt's startedTime, startedAfterSeq, nextIndex, and compact stream, and every stream member becomes a Client-only assistant/live-chunk entry ordered between durable cursors. The Host captures a follower-local arrival ordinal with that baseline and suppresses buffered frames at or before the cut; a replacement Agent may restart frame revision at one. A durable assistant/message or assistant/attempt arriving after an active opening stays staged only when its seq follows startedAfterSeq and its Turn and Step match; the matching end type, seq, and index publish it while earlier same-step retries remain visible. Revision, dense-index, or settlement gaps reopen follow, and an abandoned end publishes no durable settlement. A durable gap-repair page has no Assistant baseline, so its held notification reopens follow once for a paired page and baseline. Every history record covers exactly its event seq. A business, persistence, or unresolved continuity failure terminates the stream, while only physical carrier loss selects automatic resumption. SessionControlStream is a Gateway RemoteSnapshotStream; every generation opens with a complete process-local baseline, so reconnect replaces queue, jobs, and projection state instead of treating transient values as durable events.

The Session object also carries local submission echoes: session.beginSubmission inserts one into SessionSnapshot.pendingSubmissions synchronously, before the caller serializes and prompts, so a conversation UI can show the message on the submit click's own frame. Session derives each echo's transcript, queued, or steering placement from its current running state and the requested delivery mode, then retains that placement while serialization is in flight. The prompt's requestId is the correlation identity: the Host echoes it as the durable user source's rpcId, and queue occurrences project it as SessionQueuedItem.rpcId. An echo retires one animation frame after its durable event or queue occurrence is observed (the delay keeps it renderable until the replacement is ready), immediately when its identified prompt fails or is abandoned, and as failed on disposal; each retirement fires the registered onRetire callback exactly once. Echoes are Client memory only; reload and reconnect rebuild the conversation from durable events alone.

Configuration

Field	Default	Meaning
`coldBlankProbeMaxEvents`	`16`	Maximum stat-reported event count of a cold Session eligible for blankness verification; `0` disables the event-count gate
`coldBlankProbeMaxBytes`	`1,024`	Maximum stat-reported artifact byte size of a cold Session eligible for blankness verification when the backend offers no event count; `0` disables the byte-size gate
`nativeOpen`	platform-detected	Whether Session workspace paths can be handed to a native desktop opener

The generated configuration catalog is the exhaustive source for accepted fields and their JSDoc.

Model Experience

None, as invoked Agent commands own any model-visible effect.

KV Cache effect

No direct effect; model requests remain owned by the Agent and LLM packages.

Known Limitations and Deferred Work

Control baselines represent process-local state and therefore cannot reconstruct jobs after a Host restart.
A failed follow resumption remains visible to the caller instead of retrying indefinitely.
File-reference completion uses the shared Agent lookup and can resume a cold Session; the skills/list catalog is the non-activating alternative for skill metadata.

Dev Note

Working context for maintainers — click to expand

None.

Runtime invariant: No companion is published. Every page and frame is checked against the addressed durable Session.

README.md

Session Controller

Summary