Files
deepseek-harness/packages/api/session-controller
creatixchu 7c38fd8102 fix: deliver images reliably with steer and follow-up messages
A steer or follow-up accepted while a turn is closing is now claimed by a
fresh turn at the driver's clean exit instead of stranding in the inbox;
cancellation and pre-step rejection still park accepted work. Continuable
subagent follow-ups accept image parts: the wire is upload-shaped, the Host
admits and persists each batch before inbox acceptance, and delivery is
refused when the child model declines image input. The queue dock renders
durable image thumbnails instead of an [image] text marker.

Fixes #3186
2026-08-27 15:30:35 +08:00
..

description, kind
description kind
Host and Client session control: create, resume, prompt, follow history, and project live session state. package-reference

Session Controller

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Summary

@deepseek-ai/dsh-api-session-controller owns the Host ctx.sessionController service and the generated Client ctx.remote.session namespace. It serves Session list, search, creation, model selection, rename, fork, prompt, attachment, queue, cancellation, message-aligned history, live log following, and Host-wide control state. Use it through API Gateway when a Client needs these Session operations.

Table of Contents


Use this package

History pages and follow opening snapshots carry a discriminated SessionHistoryRecord. Both variants use { type, event }: type: 'event' carries one raw SessionWireEvent, while type: 'chunks' carries one lossless ChunkRowEvent for consecutive same-block assistant/chunk deltas. Both inner values expose type, seq, time, and data, so the Client retains each accepted record as one SessionEventLikeEntry without record-by-record conversion. A packed event's seq and time identify its first member, and data retains the fragment and timestamp-gap arrays. Live follow frames remain individual event records. 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, and log following can inspect persistence without activating an Agent; queue mutation and cancellation require the corresponding live state; model, rename, and prompt commands may explicitly resume an ordinary Session. Create and fork are the only operations that create a new Agent. The service applies one preset-aware resume policy and subagent ownership fence to its own methods and to the Typert Agent and Session lookups used by other Remote namespaces.

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. Ordinary records cover [event.seq, event.seq]; packed rows cover [event.seq, event.seq + memberCount - 1]. 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.


Configuration

Field Default Meaning
coldBlankProbeMaxBytes 1,024 Maximum physical size of a cold Session artifact eligible for blankness verification; 0 disables probes

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.

Dev Note

Working context for maintainers — click to expand

None.