Merge pinned master into status bar projection

packages/client/runtime/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/runtime/README.md
-README.md: 766d8516225cd46cb1a3a80c832d1cf55e816140
-README.zh.md: 9b514afca91f604b3e895187de3b5532bf22a692
+README.md: a116a5e4ad3070f20e6d90490f2507c1e2369c37
+README.zh.md: f375811e6f1480d6636fe4eb77746b76d6414b1e

packages/client/runtime/README.md

@@ -2,7 +2,7 @@
 
 English | [中文](README.zh.md)
 
-Client cordis boot and React-free object services: SlotsService wraps SlotCore and supplies renderer data sources; SessionsService owns Session objects and the Chat-facing list, scope, and event-window state; SessionHistoryService lazily owns independent raw-history ledgers for inspection consumers; WorkspacesService depends on SessionsService and owns Workspace objects, list/actions, default-target derivation, and the New Session blank-reuse entry (`connectWorkspace`). The runtime fans the shared Host stream into the Session, Workspace, and activated history owners without routing inspection state through Session or SessionManager. Client sessions are always Host-born (Session+Agent+cwd in one `session.create`); the client holds no pre-entity session state — a session's Agent scope (the client mirror of host dsh-scope, keyed by the shared agent/session id) is born when its row enters the list mirror and dies with the prune. Contract: api-contracts v3 §4. Each `Session` holds a generic `ProjectionValueStore` seeded from the history-tail `projections` block and updated by `session/projection` frames under higher-seq-wins; domain keys (including `todos`) are read via `projections.faceOf` / `useProjection`, not via `ConversationSnapshot`.
+Client cordis boot and React-free object services: SlotsService wraps SlotCore and supplies renderer data sources; SessionsService owns Session objects and the Chat-facing list, scope, and event-window state; SessionHistoryService lazily owns independent raw-history ledgers for inspection consumers; WorkspacesService depends on SessionsService and owns Workspace objects, list/actions, default-target derivation, and the New Session blank-reuse entry (`connectWorkspace`). The runtime fans the shared Host stream into the Session, Workspace, and activated history owners without routing inspection state through Session or SessionManager, and bridges the registry-invalidation frames to typed ctx events (`commands/changed`, `settings/changed`, `credentials/changed`, `models/changed`) so surface caches refetch without touching the stream. Client sessions are always Host-born (Session+Agent+cwd in one `session.create`); the client holds no pre-entity session state — a session's Agent scope (the client mirror of host dsh-scope, keyed by the shared agent/session id) is born when its row enters the list mirror and dies with the prune. Contract: api-contracts v3 §4. Each `Session` holds a generic `ProjectionValueStore` seeded from the history-tail `projections` block and updated by `session/projection` frames under higher-seq-wins; domain keys (including `todos`) are read via `projections.faceOf` / `useProjection`, not via `ConversationSnapshot`.
 
 ## Workspace and Session lists
 
@@ -28,6 +28,10 @@ SlotsService gives the renderer separate bare observables for `useSessions` and
 
 `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. `ISession.rename` settles the `title` projection cell directly from the unary response's `{title, seq}` under the same higher-seq-wins rule — the list row and every `useProjection('title')` reader update ahead of the push frame, whose later replay of the same seq is a no-op.
 
+## Session forking
+
+`ISessions.fork({sessionId, atSeq?, increaseTitle?})` resolves only after the child summary is locally addressable, carrying source lineage and cwd with `blank: false`; callers choose whether to open it. With `increaseTitle: true`, the client renames the child from the source session's persisted title: a trailing `(N)` or `（N）` is incremented without changing bracket style, while any other title gets ` (1)` appended; the rename is skipped when the source has no persisted title, and a rename failure rejects the promise but leaves the created child in place. This option is not sent in the Host fork request. A `workspace-attach-failed` response still identifies a child already published by the Host, so `SessionManager` reconciles that partial success before `SessionForkError` reaches the caller instead of making a retry create a duplicate child.
+
 ## 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.

packages/client/runtime/README.zh.md

@@ -2,7 +2,7 @@
 
 [English](README.md) | 中文
 
-客户端 cordis 启动与不依赖 React 的对象服务：SlotsService 包装 SlotCore 并提供 renderer 数据源；SessionsService 拥有 Session 对象以及 Chat 所需的列表、scope 和事件窗口状态；SessionHistoryService 为检查类消费方惰性拥有彼此独立的原始历史账本；WorkspacesService 依赖 SessionsService，拥有 Workspace 对象、列表／操作、默认目标派生，以及 New Session 空会话复用入口（`connectWorkspace`）。运行时把共享 Host 流分发给 Session、Workspace 和已激活的历史数据所有者，不让检查状态经过 Session 或 SessionManager。客户端会话一律由 Host 创建（一次 `session.create` 同时产生 Session、agent（智能体）和 cwd）；客户端不持有任何实体化之前的会话状态——agent scope（host dsh-scope 的客户端镜像，以 agent/session 共用 id 为键）在会话行进入列表镜像时创建，并随 prune 销毁。契约：api-contracts v3 §4。每个 `Session` 持有一个通用的 `ProjectionValueStore`，由历史记录尾部的 `projections` 块播种，并经 `session/projection` 帧按 seq 高者胜更新；领域键（含 `todos`）经 `projections.faceOf`／`useProjection` 读取，不经 `ConversationSnapshot`。
+客户端 cordis 启动与不依赖 React 的对象服务：SlotsService 包装 SlotCore 并提供 renderer 数据源；SessionsService 拥有 Session 对象以及 Chat 所需的列表、scope 和事件窗口状态；SessionHistoryService 为检查类消费方惰性拥有彼此独立的原始历史账本；WorkspacesService 依赖 SessionsService，拥有 Workspace 对象、列表／操作、默认目标派生，以及 New Session 空会话复用入口（`connectWorkspace`）。运行时把共享 Host 流分发给 Session、Workspace 和已激活的历史数据所有者，不让检查状态经过 Session 或 SessionManager，并把注册表失效帧桥接为类型化 ctx 事件（`commands/changed`、`settings/changed`、`credentials/changed`、`models/changed`），使各表面缓存无需触碰流即可重拉。客户端会话一律由 Host 创建（一次 `session.create` 同时产生 Session、agent（智能体）和 cwd）；客户端不持有任何实体化之前的会话状态——agent scope（host dsh-scope 的客户端镜像，以 agent/session 共用 id 为键）在会话行进入列表镜像时创建，并随 prune 销毁。契约：api-contracts v3 §4。每个 `Session` 持有一个通用的 `ProjectionValueStore`，由历史记录尾部的 `projections` 块播种，并经 `session/projection` 帧按 seq 高者胜更新；领域键（含 `todos`）经 `projections.faceOf`／`useProjection` 读取，不经 `ConversationSnapshot`。
 
 ## Workspace 与 Session 列表
 
@@ -28,6 +28,10 @@ SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸
 
 `SessionManager` 独立于列表和 Session 实例到达情况，保留最近一次通过验证的 `session/title` 控制快照。seq 更高的事件会替换旧快照，标题时间戳计入列表新近程度；订阅基线会先丢弃 seq 超过其 `lastSeq` 的任何已保留标题，再接收可选的折叠标题。显式移除 Session 也会清除已保留标题。因此，面向客户端的 `SessionSummary.title` 只包含实际的持久化标题；`displayTitle` 始终存在，并依次回退到 cwd basename 和 Session id。冷态持久化会话会保持该回退值，直到打开或恢复会话，促使主机折叠并投影由日志支撑的标题。`ISession.rename` 用 unary 响应中的 `{title, seq}` 直接结算 `title` 投影格，遵循同一 seq 高者胜规则——列表行和所有 `useProjection('title')` 读者在推送帧到达前即更新；推送帧随后重放同一 seq 时为无操作。
 
+## 会话 fork
+
+`ISessions.fork({sessionId, atSeq?, increaseTitle?})` 只在子会话摘要已能在本地寻址后才完成；该摘要携带源会话的谱系和 cwd，且 `blank: false`，由调用方决定是否打开。`increaseTitle: true` 会在 client 端把源会话的持久化标题改名到子会话：尾部 `(N)` 或 `（N）` 递增并保留括号样式，其余标题追加 ` (1)`；源会话没有持久化标题时跳过改名，改名失败时拒绝 promise 但保留已创建的子会话。该选项不会进入 Host fork 请求。即使响应为 `workspace-attach-failed`，其中仍会标识 Host 已发布的子会话，因此 `SessionManager` 会先将这一部分成功对账，再让 `SessionForkError` 到达调用方，避免重试创建重复的子会话。
+
 ## 会话模型选择
 
 每个常驻 `Session` 都拥有一个 `modelSelection` 快照，其中包含当前提供方/模型目标、按提供方分组的目录、逐提供方失败记录，以及 `idle`／`loading`／`ready`／`selecting`／`error` 状态。历史记录会建立或刷新当前目标，打开选择器会刷新目录；选择失败会保留上一个目标和可用分组。目录与选择操作共用单调递增的代次，因此较旧响应无法覆盖较新的选择。重连重建会恢复 Host 报告的目标，同时不替换未变化的选择子结构。

packages/client/runtime/src/client/contract/sessions.ts

@@ -29,6 +29,17 @@ export interface ISessions {
   open(id: SessionId): void
   /** Clear the current selection into the no-session view state. */
   clear(): void
+  /**
+   * Fork a session from a completed-turn prefix of the source; on resolution
+   * the child is in the list store and `open()` can target it.
+   * @param opts - source session id, the optional event seq anchoring the
+   *   cut (the boundary is the first turn/end at or after it; an in-log
+   *   anchor in an open turn is unavailable rather than clipped backward),
+   *   and whether to increment an inherited durable title before resolving.
+   * @returns the child session id.
+   * @throws when the fork fails, or when a requested child-title rename fails after creation.
+   */
+  fork(opts: { sessionId: SessionId; atSeq?: number; increaseTitle?: boolean }): Promise<SessionId>
   /**
    * Register a per-session standard-props provider (hooks become `use<Name>`
    * selector hooks on the render side; props spread verbatim).

packages/client/runtime/src/client/index.ts

@@ -122,6 +122,28 @@ declare module 'cordis' {
      * @mode emit
      */
     'commands/changed'(): void
+    /**
+     * One settings namespace's resolved value changed on the host
+     * (host/settings-changed passthrough). Subscribers refetch
+     * `settings.describe`; the frame carries no values.
+     * @mode emit
+     * @param ns - the namespace whose resolved value changed.
+     */
+    'settings/changed'(ns: string): void
+    /**
+     * One credential reference's state changed on the host
+     * (host/credentials-changed passthrough). The ref is an
+     * environment-variable NAME — never a value.
+     * @mode emit
+     * @param ref - the reference whose configured state changed.
+     */
+    'credentials/changed'(ref: string): void
+    /**
+     * The host provider topology changed (host/models-changed passthrough).
+     * Subscribers refetch `llm.providers`/`llm.models`/`session.models`.
+     * @mode emit
+     */
+    'models/changed'(): void
     /**
      * A connection generation was (re-)established. Wire-derived caches must
      * treat their state as stale and repull (commands directory; the queue
@@ -170,8 +192,13 @@ export function apply(ctx: Context): void {
       sessions.handleHostEnvelope(envelope)
       workspaces.handleHostEnvelope(envelope)
       // Typed-event bridge: the session layer ignores registry frames (no
-      // session routing); consumers (command directory caches) subscribe on ctx.
-      if (envelope.payload.type === 'host/commands-changed') ctx.emit('commands/changed')
+      // session routing); consumers (command directory caches, the settings
+      // and model surfaces) subscribe on ctx.
+      const frame = envelope.payload
+      if (frame.type === 'host/commands-changed') ctx.emit('commands/changed')
+      else if (frame.type === 'host/settings-changed') ctx.emit('settings/changed', frame.ns)
+      else if (frame.type === 'host/credentials-changed') ctx.emit('credentials/changed', frame.ref)
+      else if (frame.type === 'host/models-changed') ctx.emit('models/changed')
       try {
         sessionHistory.handleHostEnvelope(envelope)
       } catch (error) {

packages/client/runtime/src/client/session-history/source.ts

@@ -1,12 +1,14 @@
 import type {
   HistoryEntry, IApiClient, MuxFrame, RpcError, SessionId,
 } from '@deepseek-ai/dsh-client-connection/client'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import { transportError } from '@deepseek-ai/dsh-host-apiproxy/api'
 import type {
   SessionHistoryFace, SessionHistorySnapshot,
 } from '../contract/session-history.ts'
 import { createHistoryInspection } from '../sessions/history.ts'
 import { Notifier } from '../sessions/notifier.ts'
+import { PartialAccumulator } from '../sessions/partial.ts'
 
 const HISTORY_PAGE_MESSAGES = 50
 
@@ -33,6 +35,9 @@ export class SessionHistorySource implements SessionHistoryFace {
     entries: readonly HistoryEntry[]
     value: SessionHistorySnapshot['inspection']
   } | null = null
+  private streamPublishToken: object | null = null
+  private streamBaseInspection: SessionHistorySnapshot['inspection'] | null = null
+  private streamPartial: PartialAccumulator | null = null
   private snapshotCache: SessionHistorySnapshot
   private readonly notifier = new Notifier(() => {
     this.snapshotCache = this.buildSnapshot()
@@ -125,7 +130,7 @@ export class SessionHistorySource implements SessionHistoryFace {
     if (this.state !== 'cold') {
       this.state = 'cold'
       this.error = null
-      this.notifier.markDirty()
+      this.publishDirtyNow()
     }
   }
 
@@ -143,7 +148,7 @@ export class SessionHistorySource implements SessionHistoryFace {
     this.hasMore = false
     this.state = 'cold'
     this.error = null
-    this.notifier.markDirty()
+    this.publishDirtyNow()
     void this.loadForConsumers()
   }
 
@@ -155,6 +160,9 @@ export class SessionHistorySource implements SessionHistoryFace {
     this.openPromise = null
     this.olderPromise = null
     this.liveBuffer = []
+    this.streamPublishToken = null
+    this.streamBaseInspection = null
+    this.streamPartial = null
   }
 
   private open(): Promise<void> {
@@ -188,7 +196,7 @@ export class SessionHistorySource implements SessionHistoryFace {
   private async doOpen(generation: number): Promise<void> {
     this.state = 'loading'
     this.error = null
-    this.notifier.markDirty()
+    this.publishDirtyNow()
     try {
       let { result } = await this.api.sessions.history({
         sessionId: this.sessionId,
@@ -222,7 +230,7 @@ export class SessionHistorySource implements SessionHistoryFace {
       /* v8 ignore next -- transportError always returns the error branch. */
       this.error = folded.ok ? null : folded.error
     } finally {
-      if (generation === this.generation) this.notifier.markDirty()
+      if (generation === this.generation) this.publishDirtyNow()
     }
   }
 
@@ -261,7 +269,7 @@ export class SessionHistorySource implements SessionHistoryFace {
     const settled = operation.finally(() => {
       if (this.olderPromise !== settled) return
       this.olderPromise = null
-      this.notifier.markDirty()
+      this.publishDirtyNow()
     })
     this.olderPromise = settled
     return settled
@@ -286,7 +294,7 @@ export class SessionHistorySource implements SessionHistoryFace {
     const buffered = this.liveBuffer
     this.liveBuffer = []
     for (const entry of buffered) this.appendLive(entry)
-    this.notifier.markDirty()
+    this.publishDirtyNow()
   }
 
   private acceptLive(entry: HistoryEntry): void {
@@ -301,8 +309,16 @@ export class SessionHistorySource implements SessionHistoryFace {
       void this.repairGap()
       return
     }
+    if (
+      entry.event.type === 'assistant/chunk'
+      && entry.event.data.chunk.type !== 'usage'
+    ) {
+      if (!this.appendIncrementalChunk(entry, entry.event)) return
+      this.publishStreamDirty()
+      return
+    }
     this.appendLive(entry)
-    this.notifier.markDirty()
+    this.publishDirtyNow()
   }
 
   private appendLive(entry: HistoryEntry): void {
@@ -311,6 +327,66 @@ export class SessionHistorySource implements SessionHistoryFace {
     this.entries = [...this.entries, entry]
   }
 
+  /** Append a chunk against the cached finalized projection; false means no visible publish. */
+  private appendIncrementalChunk(
+    entry: HistoryEntry,
+    event: SessionEvent<'assistant/chunk'>,
+  ): boolean {
+    const { turn, step, chunk } = event.data
+    if (!isVisibleAssistantChunk(chunk.type)) {
+      const inspection = this.currentInspection()
+      this.appendLive(entry)
+      this.inspectionCache = { entries: this.entries, value: inspection }
+      return false
+    }
+    const base = this.streamBaseInspection ?? this.currentInspection()
+    this.streamBaseInspection = base
+    if (
+      this.streamPartial === null
+      || this.streamPartial.turn !== turn
+      || this.streamPartial.step !== step
+    ) {
+      const current = base.partial
+      this.streamPartial = new PartialAccumulator(
+        turn,
+        step,
+        current?.turn === turn && current.step === step ? current.blocks : [],
+      )
+    }
+    this.streamPartial.push(chunk)
+    this.appendLive(entry)
+    this.inspectionCache = {
+      entries: this.entries,
+      value: { ...base, partial: this.streamPartial.toPartial() },
+    }
+    return true
+  }
+
+  /** Coalesce token-stream projection and rendering work to one publish per browser frame. */
+  private publishStreamDirty(): void {
+    if (this.streamPublishToken !== null) return
+    const token = {}
+    this.streamPublishToken = token
+    const publish = () => {
+      if (this.streamPublishToken !== token) return
+      this.streamPublishToken = null
+      this.notifier.markDirty()
+    }
+    if (typeof globalThis.requestAnimationFrame === 'function') {
+      globalThis.requestAnimationFrame(publish)
+    } else {
+      queueMicrotask(publish)
+    }
+  }
+
+  /** Publish structural changes immediately and invalidate an older scheduled stream publish. */
+  private publishDirtyNow(): void {
+    this.streamPublishToken = null
+    this.streamBaseInspection = null
+    this.streamPartial = null
+    this.notifier.markDirty()
+  }
+
   private async repairGap(): Promise<void> {
     if (this.stitching) return
     this.stitching = true
@@ -335,6 +411,16 @@ export class SessionHistorySource implements SessionHistoryFace {
   }
 
   private buildSnapshot(): SessionHistorySnapshot {
+    return {
+      state: this.state,
+      error: this.error,
+      hasMore: this.hasMore,
+      inspection: this.currentInspection(),
+    }
+  }
+
+  /** Inspection pinned to the source's current immutable entry array. */
+  private currentInspection(): SessionHistorySnapshot['inspection'] {
     if (this.inspectionCache?.entries !== this.entries) {
       const entries = this.entries
       this.inspectionCache = {
@@ -342,11 +428,14 @@ export class SessionHistorySource implements SessionHistoryFace {
         value: createHistoryInspection(() => entries),
       }
     }
-    return {
-      state: this.state,
-      error: this.error,
-      hasMore: this.hasMore,
-      inspection: this.inspectionCache.value,
-    }
+    return this.inspectionCache.value
   }
 }
+
+function isVisibleAssistantChunk(type: string): boolean {
+  return type === 'block-start'
+    || type === 'text-delta'
+    || type === 'reasoning-delta'
+    || type === 'tool-call-delta'
+    || type === 'block-end'
+}

packages/client/runtime/src/client/sessions/manager.ts

@@ -289,6 +289,40 @@ export class SessionManager {
     }
   }
 
+  /**
+   * Contract session.fork; on success merge the child into summaries
+   * immediately (same synchronous-addressability guarantee as create). The
+   * child carries the source's history, so it is never blank; lineage rides
+   * parentSessionId so the list nests it under its source. A child published
+   * before Workspace attachment fails is also reconciled into the list.
+   * @param opts - source session and the optional seq anchoring the cut.
+   * @returns the fork result (the child session id).
+   */
+  async fork(
+    opts: { sessionId: SessionId; atSeq?: number },
+  ): Promise<RpcResult<{ sessionId: SessionId }>> {
+    try {
+      const source = this.summaries.find(s => s.sessionId === opts.sessionId)
+      const { result } = await this.api.sessions.fork({
+        sessionId: opts.sessionId,
+        ...opts.atSeq === undefined ? {} : { atSeq: opts.atSeq },
+      })
+      const childId = result.ok
+        ? result.value.sessionId
+        : workspaceAttachSessionId(result.error)
+      if (childId !== undefined) {
+        this.recordMutation({ kind: 'upsert', summary: {
+          sessionId: childId, updatedAt: Date.now(), running: false, blank: false,
+          parentSessionId: opts.sessionId,
+          ...(source?.cwd !== undefined ? { cwd: source.cwd } : {}),
+        } })
+      }
+      return result
+    } catch (error) {
+      return transportError(error)
+    }
+  }
+
   /**
    * Insert-or-enrich a locally synthesized summary: a new id prepends; an
    * existing entry only gains fields it lacks (the session-added frame and the

packages/client/runtime/src/client/sessions/partial.ts

@@ -13,8 +13,18 @@ export class PartialAccumulator {
   private changed = true
   private snapshot: PartialAssistant
 
-  constructor(readonly turn: number, readonly step: number) {
-    this.snapshot = { turn, step, blocks: [] }
+  /**
+   * @param turn - Owning agent turn.
+   * @param step - Owning model step.
+   * @param initialBlocks - Materialized prefix when accumulation begins after history replay.
+   */
+  constructor(
+    readonly turn: number,
+    readonly step: number,
+    initialBlocks: readonly AssistantBlock[] = [],
+  ) {
+    this.blocks = [...initialBlocks]
+    this.snapshot = { turn, step, blocks: initialBlocks }
   }
 
   /**

packages/client/runtime/src/client/sessions/service.ts

@@ -81,6 +81,22 @@ export class SessionCreateError extends Error {
   }
 }
 
+/** Structured session-fork failure. */
+export class SessionForkError extends Error {
+  override readonly name = 'SessionForkError'
+
+  /**
+   * @param rpcError - Host business or folded transport error.
+   * @param sourceSessionId - the session the fork was cut from.
+   */
+  constructor(
+    readonly rpcError: RpcError,
+    readonly sourceSessionId: SessionId,
+  ) {
+    super(`session fork failed: ${rpcError.code}: ${rpcError.message}`)
+  }
+}
+
 /** Session assembly handle for SessionProvider/inject factories (identity-stable per session). */
 export interface SessionBinding {
   readonly sessionId: SessionId
@@ -121,6 +137,24 @@ function displayTitleOf(title: string | undefined, cwd: string | undefined, id:
   return id
 }
 
+/**
+ * Increment a trailing fork number while preserving its half-width or
+ * full-width parentheses; an unnumbered title starts with ` (1)`.
+ * @param title - source session's durable title.
+ * @returns the title assigned to the fork child.
+ */
+function increasedForkTitle(title: string): string {
+  const ascii = /^(.*?)\((\d+)\)$/u.exec(title)
+  if (ascii?.[1] !== undefined && ascii[2] !== undefined) {
+    return `${ascii[1]}(${BigInt(ascii[2]) + 1n})`
+  }
+  const fullWidth = /^(.*?)（(\d+)）$/u.exec(title)
+  if (fullWidth?.[1] !== undefined && fullWidth[2] !== undefined) {
+    return `${fullWidth[1]}（${BigInt(fullWidth[2]) + 1n}）`
+  }
+  return `${title} (1)`
+}
+
 interface ScopeRecord {
   fiber: Fiber
   ctx: Context
@@ -317,6 +351,42 @@ export class SessionsService implements ISessions {
     return result.value.sessionId
   }
 
+  /**
+   * Fork a session from a completed-turn prefix of the source (same
+   * synchronous-addressability guarantee as {@link SessionsService.create}:
+   * on resolution the child is in the list store and open() can target it).
+   * @param opts - source session id, the optional event seq anchoring the
+   *   cut (the boundary is the first turn/end at or after it; an in-log
+   *   anchor in an open turn is unavailable rather than clipped backward),
+   *   and whether to increment an inherited durable title before resolving.
+   * @returns the child session id.
+   * @throws {SessionForkError} with the source id.
+   * @throws {Error} when a requested child-title rename fails after creation.
+   */
+  async fork(opts: {
+    sessionId: SessionId
+    atSeq?: number
+    increaseTitle?: boolean
+  }): Promise<SessionId> {
+    const sourceTitle = opts.increaseTitle
+      ? this.list.getSnapshot().byId[opts.sessionId]?.title
+      : undefined
+    const result = await this.manager.fork({
+      sessionId: opts.sessionId,
+      ...(opts.atSeq === undefined ? {} : { atSeq: opts.atSeq }),
+    })
+    if (!result.ok) throw new SessionForkError(result.error, opts.sessionId)
+    this.projectList()
+    const childId = result.value.sessionId
+    if (sourceTitle !== undefined) {
+      const child = this.binding(childId)?.session
+      if (child === undefined) throw new Error(`fork child "${childId}" is not locally addressable`)
+      const renamed = await child.rename(increasedForkTitle(sourceTitle))
+      if (!renamed.ok) throw new Error(`fork child rename failed: ${renamed.error.code}: ${renamed.error.message}`)
+    }
+    return childId
+  }
+
   /**
    * Resolve an Agent-scoped context view (use-and-discard).
    * @param id - session id (the agent identity — 1:1 same axis).

packages/client/runtime/tests/fake-api.ts

@@ -62,8 +62,9 @@ export class FakeApiClient implements IApiClient {
   // Programmable slots (defaults answer OK-empty); reassign per case.
   onList: (payload: unknown) => Promise<RpcResponse<{ items: never[] }>> = () => Promise.resolve(ok({ items: [] }))
   onCreate: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-new' as SessionId }))
-  readonly defaultModel: ModelTarget = { provider: 'deepseek', model: 'deepseek-v4-flash' }
+  readonly defaultModel: ModelTarget = { provider: 'deepseek-official', model: 'deepseek-v4-flash' }
   onRename: (payload: unknown) => Promise<RpcResponse<{ title: string; seq: number }>> = () => Promise.resolve(ok({ title: 'fk-renamed', seq: 0 }))
+  onFork: (payload: unknown) => Promise<RpcResponse<{ sessionId: SessionId }>> = () => Promise.resolve(ok({ sessionId: 'fk-fork' as SessionId }))
   onHistory: (payload: { sessionId: SessionId; beforeSeq?: number; maxMessages?: number })
   => Promise<RpcResponse<{ events: never[]; hasMore: boolean }>> =
     () => Promise.resolve(ok({ events: [], hasMore: false }))
@@ -71,7 +72,7 @@ export class FakeApiClient implements IApiClient {
   onModels: (payload: unknown) => Promise<RpcResponse<SessionModels>> = () => Promise.resolve(ok({
     current: this.defaultModel,
     groups: [{
-      id: 'deepseek',
+      id: 'deepseek-official',
       name: 'DeepSeek',
       models: [{ id: 'deepseek-v4-flash', name: 'DeepSeek V4 Flash' }],
     }],
@@ -118,6 +119,7 @@ export class FakeApiClient implements IApiClient {
     selectModel: (payload: { provider: string; model: string }) =>
       this.record('session.selectModel', payload, this.onSelectModel(payload)),
     rename: (payload: unknown) => this.record('session.rename', payload, this.onRename(payload)),
+    fork: (payload: unknown) => this.record('session.fork', payload, this.onFork(payload)),
     prompt: (payload: unknown) => this.record('session.prompt', payload, this.onPrompt(payload)),
     updateQueue: (payload: unknown) => this.record('session.updateQueue', payload, this.onUpdateQueue(payload)),
     cancel: (payload: unknown) => this.record('session.cancel', payload, this.onCancel(payload)),
@@ -181,6 +183,24 @@ export class FakeApiClient implements IApiClient {
     clear: payload => this.record('goal.clear', payload, Promise.resolve(ok({ cleared: true as const }))),
   }
 
+  readonly settings: IApiClient['settings'] = {
+    describe: payload => this.record('settings.describe', payload, Promise.resolve(ok({ writable: true, namespaces: [] }))),
+    update: payload => this.record('settings.update', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+    replace: payload => this.record('settings.replace', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+    mutate: payload => this.record('settings.mutate', payload, Promise.resolve(ok({ ns: 'fake', schema: {}, value: {}, applies: 'live' as const, secrets: [], revision: 0 }))),
+  }
+
+  readonly credentials: IApiClient['credentials'] = {
+    describe: payload => this.record('credentials.describe', payload, Promise.resolve(ok({ credentials: {} }))),
+    set: payload => this.record('credentials.set', payload, Promise.resolve(ok({}))),
+    unset: payload => this.record('credentials.unset', payload, Promise.resolve(ok({}))),
+  }
+
+  readonly llm: IApiClient['llm'] = {
+    providers: payload => this.record('llm.providers', payload, Promise.resolve(ok({ providers: [] }))),
+    models: payload => this.record('llm.models', payload, Promise.resolve(ok({ groups: [], failures: [] }))),
+  }
+
   /** When true, streams never fire onOpen (misbehaving-carrier material for the handshake timeout guard). */
   suppressStreamOpen = false
 

packages/client/runtime/tests/manager.spec.ts

@@ -277,6 +277,23 @@ describe('remaining branches', () => {
     expect(manager.getListSnapshot().items[0]).not.toHaveProperty('cwd')
   })
 
+  it('reconciles a fork child published before workspace attachment fails', async () => {
+    const api = new FakeApiClient()
+    api.onFork = () => Promise.resolve(err({
+      code: 'workspace-attach-failed',
+      message: 'forked but unattached',
+      details: { sessionId: S2, workspaceId: 'w1' },
+    } as never))
+    const manager = new SessionManager(api)
+    const result = await manager.fork({ sessionId: S1 })
+    expect(result).toMatchObject({ ok: false, error: { code: 'workspace-attach-failed' } })
+    expect(manager.getListSnapshot().items).toEqual([expect.objectContaining({
+      sessionId: S2,
+      parentSessionId: S1,
+      blank: false,
+    })])
+  })
+
   it('reconciles a preallocated id after an ordinary transport failure', async () => {
     const api = new FakeApiClient()
     api.onCreate = () => Promise.reject(new Error('response lost'))
@@ -361,7 +378,7 @@ describe('connected generation', () => {
     api.onHistory = () => Promise.resolve(ok({
       events: entries(plainTurn(0, 0, 'a', 'b')) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-chat' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-chat' },
     }))
     const manager = new SessionManager(api)
     const openedSession = manager.get(S1)

packages/client/runtime/tests/partial.spec.ts

@@ -41,6 +41,12 @@ describe('PartialAccumulator', () => {
     expect(acc.toPartial().blocks).toEqual([{ kind: 'reasoning', text: '思考' }])
   })
 
+  it('continues from a materialized history prefix', () => {
+    const acc = new PartialAccumulator(1, 0, [{ kind: 'text', text: '已有' }])
+    acc.push(chunk({ type: 'text-delta', index: 0, text: '增量' }))
+    expect(acc.toPartial().blocks).toEqual([{ kind: 'text', text: '已有增量' }])
+  })
+
   it('folds tool-call deltas: first id pins callId, late name overrides, argsRaw concatenates', () => {
     const acc = new PartialAccumulator(1, 0)
     acc.push(chunk({ type: 'tool-call-delta', index: 0, id: 'c1', argumentsDelta: '{"a"' }))

packages/client/runtime/tests/session-history-source.spec.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
 import { SessionHistorySource } from '../src/client/session-history/source.ts'
@@ -7,6 +7,10 @@ import { entries, ev, plainTurn } from './event-script.ts'
 
 const SID = 'history-s1' as SessionId
 
+afterEach(() => {
+  vi.unstubAllGlobals()
+})
+
 function histResponse(events: SessionEvent[], hasMore = false) {
   return Promise.resolve(ok({ events: entries(events) as never[], hasMore }))
 }
@@ -52,6 +56,71 @@ describe('SessionHistorySource', () => {
       .toEqual([1, 3, 6])
   })
 
+  it('publishes multiple assistant chunks once per browser frame', async () => {
+    const api = new FakeApiClient()
+    api.onHistory = () => histResponse(plainTurn(0, 0, '问', '答'))
+    const source = new SessionHistorySource(SID, api)
+    await source.loadAll()
+    const frames: FrameRequestCallback[] = []
+    vi.stubGlobal('requestAnimationFrame', (callback: FrameRequestCallback) => {
+      frames.push(callback)
+      return frames.length
+    })
+    let notifications = 0
+    const unsubscribe = source.subscribe(() => { notifications++ })
+    const before = source.getSnapshot().inspection
+    const finalizedNodes = before.eventNodes
+    const requests = before.requests
+    const contexts = before.contexts
+
+    for (const event of [
+      ev.chunkStart(6, 1),
+      ev.chunkText(7, 1, 'stream '),
+      ev.chunkText(8, 1, 'content'),
+    ]) {
+      source.handleMuxFrame({
+        type: 'session/event',
+        sessionId: SID,
+        event,
+      })
+    }
+
+    expect(frames).toHaveLength(1)
+    expect(notifications).toBe(0)
+    frames[0]?.(0)
+    await Promise.resolve()
+
+    expect(notifications).toBe(1)
+    const streamed = source.getSnapshot().inspection
+    expect(streamed.eventNodes).toBe(finalizedNodes)
+    expect(streamed.requests).toBe(requests)
+    expect(streamed.contexts).toBe(contexts)
+    expect(streamed.partial?.blocks).toEqual([
+      { kind: 'text', text: 'stream content' },
+    ])
+
+    source.handleMuxFrame({
+      type: 'session/event',
+      sessionId: SID,
+      event: ev.chunkText(9, 1, ' then final'),
+    })
+    source.handleMuxFrame({
+      type: 'session/event',
+      sessionId: SID,
+      event: ev.assistant(10, 1, 'stream content then final'),
+    })
+    await Promise.resolve()
+
+    expect(notifications).toBe(2)
+    const finalized = source.getSnapshot().inspection
+    expect(finalized.eventNodes).not.toBe(finalizedNodes)
+    expect(finalized.partial).toBeNull()
+    frames[1]?.(0)
+    await Promise.resolve()
+    expect(notifications).toBe(2)
+    unsubscribe()
+  })
+
   it('stops loading when an older page fails to advance', async () => {
     const api = new FakeApiClient()
     api.onHistory = payload => payload.beforeSeq === undefined

packages/client/runtime/tests/session.spec.ts

@@ -78,7 +78,7 @@ describe('open', () => {
     gate.resolve(ok({
       events: entries(page) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
     }))
     await opening
     const seqs = session.getSnapshot().nodes.map(n => n.seq)
@@ -135,7 +135,7 @@ describe('live event path', () => {
     expect(session.getSnapshot().composerPhase).toBe('blank')
     const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
     feed(ev.commandRun(0, 'cmd-perm', 'permission', ' danger-full-access'))
-    feed(ev.commandDone(1, 'cmd-perm', 'success', 'Permission preset: danger-full-access.'))
+    feed(ev.commandDone(1, 'cmd-perm', 'success', 'preset danger-full-access'))
     const snapshot = session.getSnapshot()
     expect(snapshot.nodes.at(-1)).toMatchObject({ kind: 'command', name: 'permission' })
     expect(snapshot.composerPhase).toBe('blank')
@@ -255,7 +255,7 @@ describe('paging', () => {
     gate.resolve(ok({
       events: entries(plainTurn(0, 0, 'a', 'b')) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
     }))
     await Promise.all([first, second])
     expect(api.callsOf('session.history')).toHaveLength(2) // open + one page, not two
@@ -571,7 +571,7 @@ describe('remaining branches', () => {
     stale.resolve(ok({
       events: entries(plainTurn(0, 0, '旧', '代')) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'stale' },
+      modelTarget: { provider: 'deepseek-official', model: 'stale' },
     })) // success, but its generation is gone
     await Promise.all([opening, resynced])
     expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9]) // only the fresh generation's window
@@ -594,7 +594,7 @@ describe('remaining branches', () => {
     secondPull.resolve(ok({
       events: entries([...plainTurn(0, 0, 'a', 'b'), ...plainTurn(6, 1, 'c', 'd')]) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'stale' },
+      modelTarget: { provider: 'deepseek-official', model: 'stale' },
     }))
     await Promise.all([opening, resynced])
     expect(session.getSnapshot().openState).toBe('open')
@@ -612,7 +612,7 @@ describe('remaining branches', () => {
     repairPull.resolve(ok({
       events: entries(plainTurn(0, 0, '旧', '页')) as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'stale' },
+      modelTarget: { provider: 'deepseek-official', model: 'stale' },
     })) // repair result: stale, dropped
     await resynced
     expect(session.getSnapshot().nodes.map(n => n.seq)).toEqual([7, 9])
@@ -657,7 +657,7 @@ describe('remaining branches', () => {
         { event: ev.toolResult(7, 1, 'h1', 'done'), view: { for: 'result', view: { card: 'generic', title: '历史果' } } },
       ] as never[],
       hasMore: false,
-      modelTarget: { provider: 'deepseek', model: 'deepseek-v4-flash' },
+      modelTarget: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
     }))
     await session.open()
     expect(session.getSnapshot().nodes.at(-1)).toMatchObject({

packages/client/runtime/tests/sessions-service.spec.ts

@@ -10,7 +10,7 @@ import { Context } from 'cordis'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
 import { SessionCreateError, SessionsService, scopeOf } from '../src/client/sessions/service.ts'
-import { FakeApiClient, deferred, ok } from './fake-api.ts'
+import { FakeApiClient, deferred, err, ok } from './fake-api.ts'
 
 const sid = (s: string): SessionId => s as SessionId
 
@@ -399,6 +399,69 @@ describe('create', () => {
   })
 })
 
+describe('fork', () => {
+  it.each([
+    ['Roadmap', 'Roadmap (1)'],
+    ['Roadmap (1)', 'Roadmap (2)'],
+    ['计划（1）', '计划（2）'],
+    ['计划 （9）', '计划 （10）'],
+  ])('increments the durable title %j after the child is published', async (sourceTitle, childTitle) => {
+    const b = bench()
+    b.svc.handleMuxEnvelope({
+      rpcId: 'source-title' as never,
+      payload: { type: 'session/projection', sessionId: sid('source'), key: 'title', value: sourceTitle, seq: 2 } as never,
+    })
+    await feedList(b, [{ id: 'source', cwd: '/work' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    b.api.onRename = (payload) => {
+      const { title } = payload as { title: string }
+      return Promise.resolve(ok({ title, seq: 3 }))
+    }
+
+    await expect(b.svc.fork({
+      sessionId: sid('source'), atSeq: 7, increaseTitle: true,
+    })).resolves.toBe('child')
+
+    expect(b.api.callsOf('session.fork')).toEqual([{ sessionId: 'source', atSeq: 7 }])
+    expect(b.api.callsOf('session.rename')).toEqual([{ sessionId: 'child', title: childTitle }])
+    await Promise.resolve()
+    expect(b.svc.list.getSnapshot().byId[sid('child')]).toMatchObject({
+      title: childTitle,
+      displayTitle: childTitle,
+      parentId: 'source',
+    })
+  })
+
+  it('does not rename without the title policy or a durable source title', async () => {
+    const b = bench()
+    await feedList(b, [{ id: 'source', cwd: '/work' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    await expect(b.svc.fork({ sessionId: sid('source'), increaseTitle: true })).resolves.toBe('child')
+    expect(b.api.callsOf('session.rename')).toEqual([])
+
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child-2') }))
+    await expect(b.svc.fork({ sessionId: sid('source') })).resolves.toBe('child-2')
+    expect(b.api.callsOf('session.rename')).toEqual([])
+  })
+
+  it('rejects when child rename fails while keeping the published child addressable', async () => {
+    const b = bench()
+    b.svc.handleMuxEnvelope({
+      rpcId: 'source-title' as never,
+      payload: { type: 'session/projection', sessionId: sid('source'), key: 'title', value: 'Roadmap', seq: 2 } as never,
+    })
+    await feedList(b, [{ id: 'source' }])
+    b.api.onFork = () => Promise.resolve(ok({ sessionId: sid('child') }))
+    b.api.onRename = () => Promise.resolve(err({
+      code: 'title-invalid', message: 'rejected', details: { sessionId: sid('child') },
+    }))
+
+    await expect(b.svc.fork({ sessionId: sid('source'), increaseTitle: true }))
+      .rejects.toThrow('fork child rename failed: title-invalid: rejected')
+    expect(b.svc.binding(sid('child'))).toBeDefined()
+  })
+})
+
 describe('scope lifecycle rides the list mirror (entity parity: no client-side pre-birth)', () => {
   it('a session-added frame births the row (blank) and makes the scope resolvable; removal prunes it', async () => {
     const b = bench()

packages/client/runtime/tests/wire-events.spec.ts

@@ -44,6 +44,22 @@ describe('wire event bridge', () => {
     expect(changed).toBe(1)
   })
 
+  it('broadcasts the settings/credentials/models invalidations with their frame payloads', async () => {
+    const bench = await mount()
+    const seen: unknown[][] = []
+    bench.ctx.on('settings/changed', ns => seen.push(['settings', ns]))
+    bench.ctx.on('credentials/changed', ref => seen.push(['credentials', ref]))
+    bench.ctx.on('models/changed', () => seen.push(['models']))
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r3' as never, payload: { type: 'host/settings-changed', ns: 'llm-pi-ai' } })
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r4' as never, payload: { type: 'host/credentials-changed', ref: 'OPENAI_API_KEY' } })
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r5' as never, payload: { type: 'host/models-changed' } })
+    expect(seen).toEqual([
+      ['settings', 'llm-pi-ai'],
+      ['credentials', 'OPENAI_API_KEY'],
+      ['models'],
+    ])
+  })
+
   it('broadcasts connection/reset on every established generation (reconnect invalidation)', async () => {
     const bench = await mount()
     let resets = 0