Merge latest master into PR 555

# Conflicts: # docs/architecture.i18n.yaml # docs/core-data-structures/core.i18n.yaml # examples/acp-agent/tests/snapshots/cordis-inspect-jsdoc/session.jsonl # packages/client/runtime/README.i18n.yaml # packages/client/ui-conversation/README.i18n.yaml # packages/client/ui-conversation/src/client/chat/MessageItem.tsx # packages/compact/compact-basic/README.i18n.yaml # packages/ui/tui/README.i18n.yaml
2026-07-31 19:39:22 +08:00
parent cc88018cd4 9b1486f90f
commit 09b7fcfd4f
187 changed files with 5806 additions and 657 deletions
--- a/packages/client/runtime/README.i18n.yaml
+++ b/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: 2af844e812aca7692c9bdd9c4ca131481a4c0db0
-README.zh.md: ad18a97bde7ac1dabde2c4b67f25dd3eb60244be
+README.md: e862b024367137a937c1995137fb98e682838cf9
+README.zh.md: ae4ca7bc0be348feb719da10e26a17580338a170
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -30,6 +30,10 @@ SlotsService gives the renderer separate bare observables for `useSessions` and

 Because the projection is log-ordered, the node array is seq-monotonic by construction: log-only `command/run` / `command/done` nodes splice in by seq, `Session` merges interrupted frozen nodes by their fractional seqs, and a window whose checkpoint cites a shadowed range outside it renders the marker with nothing logged. The marker's summary text comes from the checkpoint's `compact/summary` provenance; a window cut that left the provenance outside makes the row non-expandable rather than empty, and a later page that supplies it resolves the text. Performance contract: one append materializes at most one node and copies the projection only when it adds that node; an event that changes no node keeps the previous array reference (a chunk storm costs nothing), and unchanged nodes keep their object identity.

+## Request inspection
+
+`SessionHistoryInspection.requests` is one chronological, purpose-discriminated provider-request stream. Assistant requests always carry their numeric `turn` and `step`; compaction requests carry `step: 0` and a `turn` owner that may be `null`. That null owner means a manual compaction ran standalone between turns, not that it belongs to either adjacent turn. A `session/end-seed` boundary closes an unmatched compaction request as an error at the boundary time with `Compaction was interrupted before completion.`; a later start projects as an independent request instead of overwriting the orphan.
+
 ## Code Mode sub-dispatch index

 `ConversationSnapshot.codeDispatches` groups a `run_code` call's sub-dispatches under their parent callId, in start order, using the native call-block shapes: a `tool/code-dispatch-start` event lands the `RunningToolCall` form (rows derive the running ring from the shape) and its `tool/code-dispatch` settlement replaces it in place with the `ToolResultNode` form, `callTime` carrying the paired start's time. A settle whose start fell outside the replay window appends directly with `callTime: null` (duration unknown — never a fabricated zero). Live mux frames and history replay build the identical index; sub-calls never join the transcript `nodes` flow; per-parent array and map references are memo-stable across unrelated snapshot swaps.
@@ -40,7 +44,7 @@ Because the projection is log-ordered, the node array is seq-monotonic by constr

 ## Model retry projection

-The Session object validates plugin-owned, provider-routed `llm/retry` payloads at the event wire boundary against the producer's complete field contract, including timer, integer, status, provider-delay, and non-empty diagnostic bounds. A valid event removes the matching failed step's streaming partial and inserts a durable retry notice at the event's sequence position. The notice is `scheduled` until a following retry turn starts; an aborted or disposed source turn marks it `cancelled`, while the retry turn marks it `started`. Normal-mode notices carry their finite maximum; always-mode notices remain explicitly unbounded. Window rebuild and history replay apply the same projection, so logged chunks from the discarded attempt never reappear as an interrupted reply after refresh. A terminal turn without `llm/retry` retains the existing behavior: visible unfinalized output is frozen as an interrupted assistant node.
+The Session object validates plugin-owned, provider-routed `llm/retry` payloads at the event wire boundary against the producer's complete field contract, including timer, integer, status, provider-delay, and non-empty diagnostic bounds. A valid event removes the matching failed step's streaming partial and inserts a durable retry notice at the event's sequence position. The notice is `scheduled` until a following retry turn starts; an aborted or disposed source turn marks it `cancelled`, while the retry turn marks it `started`. Normal-mode notices carry their finite maximum; always-mode notices remain explicitly unbounded. A terminal `turn/end` error without a retry projects one `turn-error` node from its durable message and optional code; AUTH projections replace provider copy that may echo credential fragments with `API key is invalid`, while the raw diagnostic remains in the session log. A retried failure keeps only the retry notice for that attempt. Window rebuild and history replay apply the same projection, so refresh neither resurrects discarded chunks nor loses terminal failure feedback. Visible unfinalized output is frozen as an interrupted assistant node beside the terminal error.

 ## Session forking

--- a/packages/client/runtime/README.zh.md
+++ b/packages/client/runtime/README.zh.md
@@ -30,6 +30,10 @@ SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸

 由于投影按日志顺序，节点数组天然按 seq 单调：仅日志的 `command/run` / `command/done` 节点按 seq 插入，`Session` 按分数 seq 归并被打断的冻结节点，而检查点所引范围落在窗口之外的窗口会渲染出标记且不打印任何日志。标记的摘要文本来自检查点的 `compact/summary` 溯源；窗口切分把溯源留在窗口外时该行不可展开而非空白，后续补上溯源的分页会解析出文本。性能契约：一次追加最多物化一个节点，并且仅在加入该节点时复制投影；不改变任何节点的事件保持上一次的数组引用（分片风暴零成本），未变化的节点保持其对象标识。

+## 请求检查
+
+`SessionHistoryInspection.requests` 是一条按时间顺序排列、以用途为判别字段的提供方请求流。助手请求始终携带数值型 `turn` 与 `step`；压缩请求携带 `step: 0`，其 `turn` 所有者可以是 `null`。这个 null 所有者表示手动压缩独立运行在两个轮次之间，并不表示它属于任一相邻轮次。`session/end-seed` 边界会在边界时刻将未匹配的压缩请求以错误状态结束，错误固定为 `Compaction was interrupted before completion.`；后续 start 会投影为独立请求，而不会覆盖这项遗留的未匹配请求。
+
 ## Code Mode 子调用索引

 `ConversationSnapshot.codeDispatches` 按父调用的 callId 和启动顺序，用原生调用块形状组织一个 `run_code` 调用的子调用：`tool/code-dispatch-start` 事件落成 `RunningToolCall` 形状（行组件从该形状推导运行中的转圈状态），其 `tool/code-dispatch` 完结事件原位替换为 `ToolResultNode` 形状，`callTime` 携带成对 start 事件的时间。start 落在回放窗口之外的完结事件则直接追加，`callTime: null`（耗时未知——绝不伪造零耗时）。live mux 帧与历史回放构建相同的索引；子调用永不进入 transcript 的 `nodes` 流；无关快照交换不会改变每个父调用对应的数组引用和映射引用，两者均保持 memo 稳定。
@@ -40,7 +44,7 @@ SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸

 ## 模型重试投影

-Session 对象会在事件 wire 边界依据生产方的完整字段契约，验证由插件负责、按提供方路由的 `llm/retry` 载荷，包括计时器、整数、状态、提供方延迟和非空诊断字段的边界。有效事件会移除对应失败步骤的流式输出片段，并在该事件的序列位置插入一条持久的重试提示。该提示在后续重试轮次开始前为 `scheduled`；源轮次中止或被 dispose（资源释放）时，会将该提示标记为 `cancelled`，重试轮次则会将其标记为 `started`。normal mode 提示携带其有限上限；always mode 提示则保持显式无界。窗口重建与历史回放应用相同的投影，因此刷新后，来自已丢弃尝试的日志分片绝不会重新显示为中断回复。没有 `llm/retry` 的终止轮次保留现有行为：可见但尚未定稿的输出会冻结为中断的 assistant 节点。
+Session 对象会在事件 wire 边界依据生产方的完整字段契约，验证由插件负责、按提供方路由的 `llm/retry` 载荷，包括计时器、整数、状态、提供方延迟和非空诊断字段的边界。有效事件会移除对应失败步骤的流式输出片段，并在该事件的序列位置插入一条持久的重试提示。该提示在后续重试轮次开始前为 `scheduled`；源轮次中止或被 dispose（资源释放）时，会将该提示标记为 `cancelled`，重试轮次则会将其标记为 `started`。normal mode 提示携带其有限上限；always mode 提示则保持显式无界。没有重试的终态 `turn/end` 错误会从持久消息与可选错误码投影出一个 `turn-error` 节点；AUTH 投影会把可能回显凭据片段的提供方文案替换为 `API key is invalid`，原始诊断仍保留在会话日志中。进入重试的失败则只保留该次尝试的重试提示。窗口重建与历史回放应用相同的投影，因此刷新既不会让已丢弃的分片重新出现，也不会丢失终态失败反馈。可见但尚未定稿的输出会在终态错误旁冻结为中断的 assistant 节点。

 ## 会话 fork

--- a/packages/client/runtime/src/client/index.ts
+++ b/packages/client/runtime/src/client/index.ts
@@ -47,7 +47,7 @@ export type {
  AssistantTiming, CodeSubCall, CommandNode, CompactionSummaryNode, ComposerPhase,
  ContextMessageNode, ConversationNode, ConversationSnapshot, ModelRetryNode, QueuedMessage,
  RunningToolCall,
-  SteeringMessageNode, TodoItem, ToolResultNode, UnknownSurfaceNode, UserMessageNode,
+  SteeringMessageNode, TodoItem, ToolResultNode, TurnErrorNode, UnknownSurfaceNode, UserMessageNode,
 } from './sessions/conversation.ts'
 export type {
  ConversationContext, ConversationContextOriginKind,
--- a/packages/client/runtime/src/client/sessions/conversation.ts
+++ b/packages/client/runtime/src/client/sessions/conversation.ts
@@ -138,6 +138,19 @@ export type ModelRetryNode = LlmRetryEventData & {
  retryState: 'scheduled' | 'started' | 'cancelled'
 }

+/** Durable terminal failure for a turn that has no scheduled retry. */
+export interface TurnErrorNode {
+  kind: 'turn-error'
+  /** Seq of the owning turn/end event. */
+  seq: number
+  /** Unix epoch ms from the turn/end event. */
+  time: number
+  turn: number
+  step: number
+  message: string
+  code?: string
+}
+
 /** A tool result paired (when in-window) with its call head. */
 export interface ToolResultNode {
  kind: 'tool-result'
@@ -226,6 +239,7 @@ export type ConversationNode =
  | SteeringMessageNode
  | ContextMessageNode
  | ModelRetryNode
+  | TurnErrorNode
  | ToolResultNode
  | CommandNode
  | CompactionSummaryNode
--- a/packages/client/runtime/src/client/sessions/failure-display.ts
+++ b/packages/client/runtime/src/client/sessions/failure-display.ts
@@ -0,0 +1,10 @@
+/**
+ * Convert a durable failure into copy that is safe to expose in the GUI.
+ * @param failure - Structured failure preserved by the session event.
+ * @returns Display-safe copy for client projections.
+ */
+export function displayFailureMessage(failure: { code?: string; message: string }): string {
+  // Provider AUTH messages may echo a masked or partially preserved credential.
+  // Keep the raw diagnostic in the session log, but never project it into UI state.
+  return failure.code === 'AUTH' ? 'API key is invalid' : failure.message
+}
--- a/packages/client/runtime/src/client/sessions/request-inspection.ts
+++ b/packages/client/runtime/src/client/sessions/request-inspection.ts
@@ -8,6 +8,7 @@ import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import type {
  AssistantProvenanceView, AssistantRequestConfig,
 } from './conversation.ts'
+import { displayFailureMessage } from './failure-display.ts'

 export type {
  AssistantProvenanceView, AssistantRequestConfig,
@@ -35,40 +36,55 @@ export interface RequestPromptChange {
  previous?: ConversationPromptSnapshot
 }

-/** One provider request reconstructed from durable request lifecycle events. */
-export interface RequestView {
-  /** Request category; compaction is a purpose, not a separate projection. */
-  purpose: 'assistant' | 'compaction'
+/** Lifecycle fields shared by ordinary generation and compaction requests. */
+interface RequestViewBase {
  /** Sequence that opened the operation represented by this request. */
  startSeq: number
-  turn: number
-  /** Agent-loop step, or zero for a direct compaction request. */
-  step: number
  startedAt: number
  completedAt: number | null
  status: 'running' | 'complete' | 'error'
  error?: string
-  /** Effective ordinary request input, inherited until a later header changes it. */
-  prompt?: ConversationPromptSnapshot
-  /** Prompt change logged while preparing this request. */
-  promptChange?: RequestPromptChange
  provenance?: AssistantProvenanceView
  requestConfig?: AssistantRequestConfig
  usage?: unknown
  /** Assistant message or compaction summary sequence produced by this request. */
  resultSeq?: number
+}
+
+/** One ordinary assistant generation reconstructed from durable request events. */
+interface AssistantRequestView extends RequestViewBase {
+  purpose: 'assistant'
+  turn: number
+  /** Agent-loop step that issued this request. */
+  step: number
+  /** Effective ordinary request input, inherited until a later header changes it. */
+  prompt?: ConversationPromptSnapshot
+  /** Prompt change logged while preparing this request. */
+  promptChange?: RequestPromptChange
+  /** Retry ordinal scheduled after a failed ordinary request. */
+  retry?: number
+  maxRetries?: number
+  retryDelayMs?: number
+}
+
+/** One compaction provider request, either turn-owned or standalone between turns. */
+interface CompactionRequestView extends RequestViewBase {
+  purpose: 'compaction'
+  /** Owning turn, or `null` when manual compaction ran between turns. */
+  turn: number | null
+  /** Direct compaction requests do not consume an agent-loop step. */
+  step: 0
  /** Compaction replacement message sequence, when one was committed. */
  replacementSeq?: number
  /** Safe compaction summary projection. */
  summary?: readonly ContentBlock[]
  /** Complete compaction provider output before the safe projection. */
  rawOutput?: readonly ContentBlock[]
-  /** Retry ordinal scheduled after a failed ordinary request. */
-  retry?: number
-  maxRetries?: number
-  retryDelayMs?: number
 }

+/** One provider request reconstructed from durable request lifecycle events. */
+export type RequestView = AssistantRequestView | CompactionRequestView
+
 /** Immutable request-centric projection derived from one history window. */
 export interface RequestInspectionSnapshot {
  requests: readonly RequestView[]
@@ -110,7 +126,7 @@ interface CompactionStartEvent {
  type: 'compact/start'
  seq: number
  time: number
-  data: { turn: number }
+  data: { turn: number | null }
 }

 interface CompactionSummaryEvent {
@@ -131,7 +147,7 @@ interface CompactionEndEvent {
  type: 'compact/end'
  seq: number
  time: number
-  data: { turn: number; error?: string }
+  data: { turn: number | null; error?: string }
 }

 function requestKey(turn: number, step: number): string {
@@ -228,10 +244,21 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
  let activePrompt: ConversationPromptSnapshot | undefined
  let activeCompaction: number | undefined

-  const update = (index: number | undefined, change: Partial<RequestView>): void => {
+  const updateAssistant = (
+    index: number | undefined,
+    change: Partial<Omit<AssistantRequestView, 'purpose'>>,
+  ): void => {
    if (index === undefined) return
    const request = requests[index]
-    if (request !== undefined) requests[index] = { ...request, ...change }
+    if (request?.purpose === 'assistant') requests[index] = { ...request, ...change }
+  }
+  const updateCompaction = (
+    index: number | undefined,
+    change: Partial<Omit<CompactionRequestView, 'purpose'>>,
+  ): void => {
+    if (index === undefined) return
+    const request = requests[index]
+    if (request?.purpose === 'compaction') requests[index] = { ...request, ...change }
  }

  for (const sourceEvent of events) {
@@ -263,7 +290,7 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
      }
      const change = promptChange(activePrompt, prompt, sourceEvent)
      activePrompt = prompt
-      update(activeStep === undefined ? undefined : ordinaryByStep.get(activeStep), {
+      updateAssistant(activeStep === undefined ? undefined : ordinaryByStep.get(activeStep), {
        prompt,
        requestConfig: prompt.config,
        ...(change === undefined ? {} : { promptChange: change }),
@@ -278,8 +305,11 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
        requestKey(sourceEvent.data.turn, sourceEvent.data.step),
      )
      const request = index === undefined ? undefined : requests[index]
-      update(index, {
-        usage: addTokenUsage(request?.usage, sourceEvent.data.chunk.usage),
+      updateAssistant(index, {
+        usage: addTokenUsage(
+          request?.purpose === 'assistant' ? request.usage : undefined,
+          sourceEvent.data.chunk.usage,
+        ),
      })
      continue
    }
@@ -288,7 +318,7 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
        requestKey(sourceEvent.data.turn, sourceEvent.data.step),
      )
      const request = index === undefined ? undefined : requests[index]
-      update(index, {
+      updateAssistant(index, {
        completedAt: sourceEvent.time,
        status: 'complete',
        resultSeq: sourceEvent.seq,
@@ -296,7 +326,9 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
          provider: sourceEvent.data.message.source.provider,
          model: sourceEvent.data.message.source.model,
        },
-        ...(request?.usage !== undefined || sourceEvent.data.usage === undefined
+        ...(request?.purpose === 'assistant'
+          && request.usage !== undefined
+          || sourceEvent.data.usage === undefined
          ? {}
          : { usage: sourceEvent.data.usage }),
      })
@@ -306,8 +338,8 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
      const key = requestKey(sourceEvent.data.turn, sourceEvent.data.step)
      const index = ordinaryByStep.get(key)
      const request = index === undefined ? undefined : requests[index]
-      if (request?.status === 'running') {
-        update(index, {
+      if (request?.purpose === 'assistant' && request.status === 'running') {
+        updateAssistant(index, {
          completedAt: sourceEvent.time,
          status: 'error',
        })
@@ -317,9 +349,9 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
    }
    if ((sourceEvent.type as string) === 'llm/retry') {
      const event = sourceEvent as unknown as RetryEvent
-      update(ordinaryByStep.get(requestKey(event.data.turn, event.data.step)), {
+      updateAssistant(ordinaryByStep.get(requestKey(event.data.turn, event.data.step)), {
        status: 'error',
-        error: event.data.failure.message,
+        error: displayFailureMessage(event.data.failure),
        retry: event.data.retry,
        maxRetries: event.data.maxRetries,
        retryDelayMs: event.data.delayMs,
@@ -328,14 +360,23 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
    }
    if (sourceEvent.type === 'turn/end' && sourceEvent.data.reason.kind === 'error') {
      const reason = sourceEvent.data.reason
-      update(ordinaryByStep.get(requestKey(sourceEvent.data.turn, reason.step)), {
+      updateAssistant(ordinaryByStep.get(requestKey(sourceEvent.data.turn, reason.step)), {
        status: 'error',
-        error: 'failure' in reason ? reason.failure.message : reason.message,
+        error: displayFailureMessage('failure' in reason ? reason.failure : reason),
      })
      continue
    }

    const type = sourceEvent.type as string
+    if (type === 'session/end-seed' && activeCompaction !== undefined) {
+      updateCompaction(activeCompaction, {
+        completedAt: sourceEvent.time,
+        status: 'error',
+        error: 'Compaction was interrupted before completion.',
+      })
+      activeCompaction = undefined
+      continue
+    }
    if (type === 'compact/start') {
      const event = sourceEvent as unknown as CompactionStartEvent
      activeCompaction = requests.length
@@ -352,7 +393,7 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
    }
    if (type === 'compact/summary' && activeCompaction !== undefined) {
      const event = sourceEvent as unknown as CompactionSummaryEvent
-      update(activeCompaction, {
+      updateCompaction(activeCompaction, {
        resultSeq: event.seq,
        summary: event.data.summary,
        ...(event.data.rawOutput === undefined ? {} : { rawOutput: event.data.rawOutput }),
@@ -375,12 +416,12 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
      && activeCompaction !== undefined
      && isCompactionSource(sourceEvent.data.source)
    ) {
-      update(activeCompaction, { replacementSeq: sourceEvent.seq })
+      updateCompaction(activeCompaction, { replacementSeq: sourceEvent.seq })
      continue
    }
    if (type !== 'compact/end' || activeCompaction === undefined) continue
    const event = sourceEvent as unknown as CompactionEndEvent
-    update(activeCompaction, {
+    updateCompaction(activeCompaction, {
      completedAt: event.time,
      status: event.data.error === undefined ? 'complete' : 'error',
      ...(event.data.error === undefined ? {} : { error: event.data.error }),
--- a/packages/client/runtime/src/client/sessions/session.ts
+++ b/packages/client/runtime/src/client/sessions/session.ts
@@ -20,6 +20,7 @@ import type {
 import type { PendingInteraction } from './pending.ts'
 import { PendingWait } from './pending.ts'
 import { TranscriptAdapter } from './transcript-adapter.ts'
+import { displayFailureMessage } from './failure-display.ts'
 import { Notifier } from './notifier.ts'
 import { PartialAccumulator } from './partial.ts'
 import { ProjectionValueStore } from './projection-store.ts'
@@ -772,6 +773,22 @@ export class Session implements SessionFace {
        if (event.data.reason.kind === 'aborted' || event.data.reason.kind === 'disposed') {
          this.settleScheduledRetry('cancelled', event.data.turn)
        }
+        if (
+          event.data.reason.kind === 'error'
+          && !this.derivedNodes.some(node => node.kind === 'model-retry' && node.turn === event.data.turn)
+        ) {
+          const failure = 'failure' in event.data.reason ? event.data.reason.failure : event.data.reason
+          this.derivedNodes.push({
+            kind: 'turn-error',
+            seq: event.seq,
+            time: event.time,
+            turn: event.data.turn,
+            step: event.data.reason.step,
+            message: displayFailureMessage(failure),
+            ...(failure.code === undefined ? {} : { code: failure.code }),
+          })
+          this.derivedRev++
+        }
        // Aborted turns never finalize. The accumulated partial is VALUE, not residue: freeze it
        // into an interrupted terminal node (pulse stops, text survives) instead of deleting it.
        // Shared by live and window-replay paths, so a refresh reconstructs the same frozen node
--- a/packages/client/runtime/tests/request-inspection.spec.ts
+++ b/packages/client/runtime/tests/request-inspection.spec.ts
@@ -85,6 +85,68 @@ describe('inspectRequests', () => {
    expect(snapshot.callSchemas.get('call-1')?.name).toBe('read')
  })

+  it('preserves a standalone compaction owner without widening assistant turns', () => {
+    const snapshot = inspectRequests(entriesOf([
+      at(0, 'compact/start', { turn: null }),
+      at(1, 'compact/summary', {
+        summary: [{ type: 'text', text: 'standalone summary' }],
+        provider: 'fake',
+        model: 'compact-model',
+      }),
+      at(2, 'compact/end', { turn: null }),
+      at(3, 'step/start', { turn: 2, step: 1 }),
+    ]))
+
+    const [compaction, assistant] = snapshot.requests
+    expect(compaction).toMatchObject({
+      purpose: 'compaction',
+      turn: null,
+      step: 0,
+      status: 'complete',
+    })
+    expect(assistant).toMatchObject({
+      purpose: 'assistant',
+      turn: 2,
+      step: 1,
+      status: 'running',
+    })
+    if (assistant?.purpose === 'assistant') {
+      const turn: number = assistant.turn
+      expect(turn).toBe(2)
+    }
+  })
+
+  it('interrupts an orphaned compaction at end-seed before projecting a new attempt', () => {
+    const snapshot = inspectRequests(entriesOf([
+      at(0, 'compact/start', { turn: null }),
+      at(1, 'session/end-seed', {}),
+      at(2, 'compact/start', { turn: null }),
+      at(3, 'compact/summary', {
+        summary: [{ type: 'text', text: 'replacement summary' }],
+        provider: 'fake',
+        model: 'compact-model',
+      }),
+      at(4, 'compact/end', { turn: null }),
+    ]))
+
+    expect(snapshot.requests).toMatchObject([
+      {
+        purpose: 'compaction',
+        startSeq: 0,
+        status: 'error',
+        completedAt: 1_700_000_000_001,
+        error: 'Compaction was interrupted before completion.',
+      },
+      {
+        purpose: 'compaction',
+        startSeq: 2,
+        status: 'complete',
+        completedAt: 1_700_000_000_004,
+        summary: [{ type: 'text', text: 'replacement summary' }],
+      },
+    ])
+  })
+
  it('captures schemas for nested tool dispatches from the active request header', () => {
    const snapshot = inspectRequests(entriesOf([
      at(0, 'request/header', {
@@ -159,6 +221,33 @@ describe('inspectRequests', () => {
    })
  })

+  it('keeps provider credential fragments out of projected request errors', () => {
+    const snapshot = inspectRequests(entriesOf([
+      at(0, 'step/start', { turn: 1, step: 1 }),
+      at(1, 'turn/end', {
+        turn: 1,
+        reason: {
+          kind: 'error',
+          step: 1,
+          failure: {
+            code: 'AUTH',
+            message: 'Authentication Fails, Your api key: sk-preview-secret is invalid',
+          },
+        },
+      }),
+      at(2, 'step/start', { turn: 2, step: 1 }),
+      at(3, 'turn/end', {
+        turn: 2,
+        reason: { kind: 'error', step: 1, message: 'plugin exploded' },
+      }),
+    ]))
+
+    expect(snapshot.requests).toMatchObject([
+      { status: 'error', error: 'API key is invalid' },
+      { status: 'error', error: 'plugin exploded' },
+    ])
+  })
+
  it('treats a scrubbed durable-fixture tool catalog as unavailable', () => {
    const snapshot = inspectRequests(entriesOf([
      at(0, 'step/start', { turn: 1, step: 1 }),
@@ -179,6 +268,7 @@ describe('inspectRequests', () => {
    ]))

    expect(snapshot.callSchemas).toEqual(new Map())
-    expect(snapshot.requests[0]?.prompt?.tools).toEqual([])
+    const [request] = snapshot.requests
+    expect(request?.purpose === 'assistant' ? request.prompt?.tools : undefined).toEqual([])
  })
 })
--- a/packages/client/runtime/tests/session.spec.ts
+++ b/packages/client/runtime/tests/session.spec.ts
@@ -211,6 +211,7 @@ describe('live event path', () => {
    for (const event of retryTurn.slice(7)) feed(event)
    snapshot = session.getSnapshot()
    expect(snapshot.nodes.slice(-2).map(node => node.kind)).toEqual(['model-retry', 'assistant'])
+    expect(snapshot.nodes.some(node => node.kind === 'turn-error')).toBe(false)
    expect(snapshot.nodes.at(-2)).toMatchObject({ kind: 'model-retry', retryState: 'started' })
    expect(snapshot.nodes.at(-1)).toMatchObject({ kind: 'assistant', blocks: [{ kind: 'text', text: '完整回复' }] })

@@ -221,6 +222,50 @@ describe('live event path', () => {
    expect(replay.session.getSnapshot().partial).toBeNull()
  })

+  it('projects unretried terminal failures at turn/end and reproduces them from history', async () => {
+    const { session } = await opened()
+    const feed = (event: SessionEvent) => {
+      session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event })
+    }
+    const failedTurns = [
+      ev.turnStart(6, 1),
+      ev.user(7, '鉴权失败'),
+      at(8, {
+        type: 'turn/end',
+        data: {
+          turn: 1,
+          reason: {
+            kind: 'error',
+            step: 0,
+            failure: {
+              code: 'AUTH',
+              message: 'Authentication Fails, Your api key: sk-preview-secret is invalid',
+            },
+          },
+        },
+      }),
+      ev.turnStart(9, 2),
+      ev.user(10, '内部失败'),
+      at(11, {
+        type: 'turn/end',
+        data: { turn: 2, reason: { kind: 'error', step: 1, message: 'plugin exploded' } },
+      }),
+    ]
+    for (const event of failedTurns) feed(event)
+
+    const errors = session.getSnapshot().nodes.filter(node => node.kind === 'turn-error')
+    expect(errors).toMatchObject([
+      { seq: 8, turn: 1, step: 0, code: 'AUTH', message: 'API key is invalid' },
+      { seq: 11, turn: 2, step: 1, message: 'plugin exploded' },
+    ])
+    expect('code' in errors[1]!).toBe(false)
+
+    const replay = makeSession()
+    replay.api.onHistory = () => histResponse([...plainTurn(0, 0, 'a', 'b'), ...failedTurns])
+    await replay.session.open()
+    expect(replay.session.getSnapshot().nodes).toEqual(session.getSnapshot().nodes)
+  })
+
  it('rejects retry payloads outside the producer contract without retracting the current partial', async () => {
    const { session } = await opened()
    const feed = (event: SessionEvent) => { session.handleMuxEnvelope('r' as never, { type: 'session/event', sessionId: SID, event }) }
--- a/packages/client/ui-conversation/README.i18n.yaml
+++ b/packages/client/ui-conversation/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/ui-conversation/README.md
-README.md: 10c1fdcdfbe9d7bfdf5f19767d7898ffc5163f99
-README.zh.md: db3a20bfd0b318e1f721e6d374f39206e7565adb
+README.md: 2dafe3c69bb087550f6c0f7faab12bff1f1324ac
+README.zh.md: 4201441c6c6397b7b35fe0fab99fc6fc6271719f
--- a/packages/client/ui-conversation/README.md
+++ b/packages/client/ui-conversation/README.md
@@ -24,7 +24,7 @@ A `read` call declaring the `read` render intent renders the returned file windo

 A tool call declaring the `diff` render intent (the `write`/`edit` tools) renders its applied change inline through ui-primitives' `DiffBlock`, the same four-layer shape. `contract/diff-card-model.ts` is the single derivation from the `callView`/`resultView` pair; the settled result's hunks replace the call-time diff, and it yields null — the generic path — for any other card tag or a generic result view (write/edit's execution errors). The keyed `FileMutationRow` (registered under both `write` and `edit`) composes the shared `ToolRow`, feeding the diff as ToolRow's `diff` body, so it is the row's collapsed-by-default expanded card; the summary path link still opens the file through the host, and an errored mutation (no diff card) surfaces its error text through ToolRow's Output section with the first line in the collapsed summary. The render-site fallback and the details panel are diff-aware too. Rows cap at `CHAT_DIFF_MAX_LINES` (8) against the panel's 16 ([decision](../../../.agents/notes/implemented/feature/2026-07-30-web-diff-card.md)).

-The chat flow projects consecutive model-retry nodes across retry turns into one stable, muted status row updated to the latest attempt; every retry event remains in the runtime snapshot and session log. Its frontend countdown anchors the scheduled delay to client receipt, avoiding host/browser clock skew, rounds remaining time up to seconds, and has a one-second floor. The latest unresolved retry uses a left-to-right text shimmer. Subsequent turn facts distinguish an attempt that started from one cancelled during backoff, while the Host running bit only controls the live animation; the row then shows a static completed or cancelled label. Normal policy rows show the finite retry maximum; always policy rows show `∞`. Activating the row reveals the latest exact retry delay and failure message. The client runtime removes each failed step's streaming tail before its retry node arrives, while the status remains visible after a later attempt succeeds.
+The chat flow projects consecutive model-retry nodes across retry turns into one stable, muted status row updated to the latest attempt; every retry event remains in the runtime snapshot and session log. Its frontend countdown anchors the scheduled delay to client receipt, avoiding host/browser clock skew, rounds remaining time up to seconds, and has a one-second floor. The latest unresolved retry uses a left-to-right text shimmer. Subsequent turn facts distinguish an attempt that started from one cancelled during backoff, while the Host running bit only controls the live animation; the row then shows a static completed or cancelled label. Normal policy rows show the finite retry maximum; always policy rows show `∞`. Activating the row reveals the latest exact retry delay and failure message. The client runtime removes each failed step's streaming tail before its retry node arrives, while the status remains visible after a later attempt succeeds. An unretried terminal failure renders as a persistent inline status at its turn boundary, showing the display-safe durable message and optional error code without offering an action the Host cannot fulfill; AUTH copy never echoes provider-supplied credential fragments.

 A `grep`/`glob` call declaring the `search` render intent renders its result inline, at the same render sites, through ui-primitives' `SearchBlock` — grep's matches grouped by file (each a collapsible header of `lineNumber: line` rows), glob's flat path list. `contract/search-card-model.ts` is the single derivation from the snapshot's `resultView`; unlike the terminal card it reads no `callView`, since a search has no matches or paths before `execute`, so a running search shows its summary alone. It yields null — the generic path — for any non-search result view, a `card` or `kind` this client version does not compile, and (because those ride the untrusted wire frame) a known kind whose `files`/`paths` is malformed. The keyed `SearchRow`, registered under both `grep` and `glob` since the derived `kind` decides the shape, composes the shared `ToolRow`, feeding the card as ToolRow's `search` body, so it is the row's collapsed-by-default expanded card; the render-site fallback routes it the same way. Both cap at `CHAT_SEARCH_MAX_LINES` (8) against the panel's 16. A capped search drops rows from the card, but the locator to the rest — grep/glob's `Full … stored at …` footer — lives only in the result text, so the derivation surfaces that as a recovery footer below the card when (and only when) the result was truncated; a settled call with no card at all (an errored search, a nested `run_code` sub-dispatch, a legacy generic result) surfaces its flattened result text through ToolRow's Output section so nothing is lost behind a bare summary ([decision](../../../.agents/notes/implemented/feature/2026-07-30-web-search-card.md)).

--- a/packages/client/ui-conversation/README.zh.md
+++ b/packages/client/ui-conversation/README.zh.md
@@ -22,7 +22,7 @@

 声明 `diff` 渲染意图的工具调用（`write`／`edit` 工具），通过 ui-primitives 的 `DiffBlock` 内联渲染其已应用的改动，采用同一套四层结构。`contract/diff-card-model.ts` 是从 `callView`／`resultView` 对推导的唯一位置；已结算 result 的 hunk 替换 call 时 diff，对任何其他 card 标签或 generic result view（write/edit 的执行错误）它返回 null，落回通用路径。键控的 `FileMutationRow`（在 `write` 与 `edit` 下都注册）组合共享的 `ToolRow`，把 diff 作为 ToolRow 的 `diff` body 传入，因此它是该行默认折叠的展开卡片；摘要路径链接仍经 host 打开文件，而出错的改动（没有 diff 卡片）经 ToolRow 的 Output 区呈现其错误文本，首行进入折叠摘要。渲染点兜底行与详情面板同样感知 diff。行的上限是 `CHAT_DIFF_MAX_LINES`（8），面板为 16（[决策](../../../.agents/notes/implemented/feature/2026-07-30-web-diff-card.md)）。

-聊天流会将跨重试轮次连续出现的模型重试节点投影为一个稳定的弱化状态行，并用最新一次尝试更新该行；每个重试事件仍保留在运行时快照与会话日志中。前端倒计时以客户端收到事件的时刻为计划延迟的起点，避免 Host 与浏览器的时钟偏差；剩余时间向上取整到秒，且下限为 1 秒。最近一次尚未完成的重试会显示从左到右的文字渐变动画。后续轮次事实用于区分已开始的尝试与在退避期间取消的尝试，Host 的 running 位只控制实时动画；随后该行会显示静态的已完成或已取消标签。normal 策略行显示有限重试上限；always 策略行显示 `∞`。激活该行会显示最近一次重试的精确延迟和失败消息。客户端运行时会在相应重试节点到达前移除每个失败步骤的流式输出尾部；后续某次尝试成功后，该状态仍保持可见。
+聊天流会将跨重试轮次连续出现的模型重试节点投影为一个稳定的弱化状态行，并用最新一次尝试更新该行；每个重试事件仍保留在运行时快照与会话日志中。前端倒计时以客户端收到事件的时刻为计划延迟的起点，避免 Host 与浏览器的时钟偏差；剩余时间向上取整到秒，且下限为 1 秒。最近一次尚未完成的重试会显示从左到右的文字渐变动画。后续轮次事实用于区分已开始的尝试与在退避期间取消的尝试，Host 的 running 位只控制实时动画；随后该行会显示静态的已完成或已取消标签。normal 策略行显示有限重试上限；always 策略行显示 `∞`。激活该行会显示最近一次重试的精确延迟和失败消息。客户端运行时会在相应重试节点到达前移除每个失败步骤的流式输出尾部；后续某次尝试成功后，该状态仍保持可见。未进入重试的终态失败会在其轮次边界渲染为持久的内联状态，展示适合显示的持久消息与可选错误码，但不会提供 Host 无法兑现的操作；AUTH 文案绝不会回显提供方给出的凭据片段。

 声明 `search` 渲染意图的 `grep`／`glob` 调用，会在同样的渲染点上通过 ui-primitives 的 `SearchBlock` 内联渲染其结果——grep 的匹配按文件分组（每个是一个可折叠的头，下辖 `lineNumber: line` 行），glob 是扁平路径列表。`contract/search-card-model.ts` 是从快照的 `resultView` 推导的唯一位置；与终端卡片不同，它不读 `callView`，因为搜索在 `execute` 前没有匹配或路径，所以运行中的搜索只显示摘要。对任何非搜索的结果视图、当前客户端版本无法编译的 `card` 或 `kind`、以及（因为这些都与不可信的 wire 帧同行）一个 `files`／`paths` 格式错误的已知 kind，它都返回 null，落回通用路径。键控的 `SearchRow` 因推导出的 `kind` 决定形态而同时注册在 `grep` 与 `glob` 下，组合共享的 `ToolRow`，把卡片作为 ToolRow 的 `search` body 传入，因此它是该行默认折叠的展开卡片；渲染点兜底行以同样方式渲染它。两者上限都是 `CHAT_SEARCH_MAX_LINES`（8），面板为 16。被截断的搜索会从卡片里丢掉一些行，但通往其余部分的定位符——grep/glob 的 `Full … stored at …` 脚注——只存在于结果文本里，因此推导在（且仅在）结果被截断时把它作为恢复脚注画在卡片下方；一个完全没有卡片的已结算调用（出错的搜索、嵌套 `run_code` 子派发、旧日志的 generic 结果）则经 ToolRow 的 Output 区呈现其压平后的结果文本，从而不让任何内容丢失在一个光秃秃的摘要之后（[决策](../../../.agents/notes/implemented/feature/2026-07-30-web-search-card.md)）。

--- a/packages/client/ui-conversation/src/client/chat/MessageItem.module.css
+++ b/packages/client/ui-conversation/src/client/chat/MessageItem.module.css
@@ -200,6 +200,40 @@
  color: var(--dsw-alias-label-secondary);
 }

+.turnErrorRow {
+  display: grid;
+  grid-template-columns: 10px minmax(0, 1fr) auto;
+  gap: 8px;
+  align-items: start;
+  padding: 2px 0;
+  font-size: 13px;
+  line-height: 20px;
+}
+
+.turnErrorDot {
+  margin-top: 5px;
+}
+
+.turnErrorCopy {
+  min-width: 0;
+  overflow-wrap: anywhere;
+}
+
+.turnErrorTitle {
+  margin-right: 6px;
+  color: var(--dsw-alias-state-error-primary);
+  font-weight: 600;
+}
+
+.turnErrorMessage {
+  color: var(--dsw-alias-label-secondary);
+}
+
+.turnErrorCode {
+  color: var(--dsw-alias-label-tertiary);
+  font: var(--dsw-font-markdown-code-block-small);
+}
+
@keyframes retry-shimmer {
  from {
    background-position: 100% 50%;
--- a/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
+++ b/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
@@ -6,9 +6,9 @@ import { memo, useEffect, useMemo, useState } from 'react'
 import type { ReactNode } from 'react'
 import type {
  CompactionSummaryNode, ContextMessageNode, ModelRetryNode, SteeringMessageNode,
-  UnknownSurfaceNode, UserMessageNode,
+  TurnErrorNode, UnknownSurfaceNode, UserMessageNode,
 } from '@deepseek-ai/dsh-client-runtime/client'
-import { JsonBlock, MessageText } from '@deepseek-ai/dsh-client-ui-primitives'
+import { JsonBlock, MessageText, StateDot } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { ChatViewSlotProps } from '../contract/slots.ts'
 import { CompactionItem } from './CompactionItem.tsx'
 import { ContextInjectionRow } from './ContextInjectionRow.tsx'
@@ -17,7 +17,14 @@ import css from './MessageItem.module.css'
 import { ImageGallery, type ImageLoader } from './MessageImage.tsx'

 export interface MessageItemProps {
-  node: UserMessageNode | SteeringMessageNode | ContextMessageNode | CompactionSummaryNode | ModelRetryNode | UnknownSurfaceNode
+  node:
+    | UserMessageNode
+    | SteeringMessageNode
+    | ContextMessageNode
+    | CompactionSummaryNode
+    | ModelRetryNode
+    | TurnErrorNode
+    | UnknownSurfaceNode
  loadImage?: ImageLoader
  retryActive?: boolean
  /** Fork the session through the turn containing this message (user-bubble branch action). */
@@ -121,6 +128,24 @@ function ModelRetryItem({ node, active, t }: {
    </details>
  )
 }
+
+/** Persistent, turn-positioned feedback for a terminal failure. */
+function TurnErrorItem({ node, t }: {
+  node: TurnErrorNode
+  t: ChatViewSlotProps['t']
+}) {
+  return (
+    <div className={css.turnErrorRow} role="status">
+      <StateDot state="error" className={css.turnErrorDot} />
+      <div className={css.turnErrorCopy}>
+        <span className={css.turnErrorTitle}>{t('message.turnError')}</span>
+        <span className={css.turnErrorMessage}>{node.message}</span>
+      </div>
+      {node.code !== undefined && <code className={css.turnErrorCode}>{node.code}</code>}
+    </div>
+  )
+}
+
 /**
 * Display projection of reference forms in a user bubble (free geometry — no
 * textarea alignment constraint here); everything else stays plain text. The
@@ -214,6 +239,8 @@ export const MessageItem = memo(function MessageItem({
      return <CompactionItem node={node} t={t} />
    case 'model-retry':
      return <ModelRetryItem node={node} active={retryActive} t={t} />
+    case 'turn-error':
+      return <TurnErrorItem node={node} t={t} />
    default:
      return (
        <div className={css.contextRow}>
--- a/packages/client/ui-conversation/src/client/locales.ts
+++ b/packages/client/ui-conversation/src/client/locales.ts
@@ -77,6 +77,7 @@ export const zh = {
  'message.retry.status': '{label}（{retry}/{maximum}） · {seconds}s',
  'message.retry.delay': '重试延迟：',
  'message.retry.failure': '失败原因：',
+  'message.turnError': '本轮运行失败',
  'command.running': '执行中…',
  'command.failed': '命令失败',
  'command.done': '已完成',
@@ -191,6 +192,7 @@ export const en = {
  'message.retry.status': '{label} ({retry}/{maximum}) · {seconds}s',
  'message.retry.delay': 'Retry delay: ',
  'message.retry.failure': 'Failure reason: ',
+  'message.turnError': 'This turn failed',
  'command.running': 'Running…',
  'command.failed': 'Command failed',
  'command.done': 'Completed',
--- a/packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx
+++ b/packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx
@@ -22,6 +22,7 @@ export function ConversationRoot({
  const session = useSession(s => s)
  const inputState = useInput(s => s)
  const cwd = useSessions(s => sessionId === undefined ? undefined : s.byId[sessionId]?.cwd)
+  const summaryBlank = useSessions(s => sessionId === undefined ? undefined : s.byId[sessionId]?.blank)
  const workspaces = useWorkspaces(s => s)

  const [pickerOpen, setPickerOpen] = useState(false)
@@ -65,8 +66,16 @@ export function ConversationRoot({
  // While a session is still replaying (loading + blank) the hero/docked
  // choice is unknowable — render the composer hidden instead of flashing
  // the centered hero and snapping to the docked bar (or vice versa).
+  // Exemption: a session the list summary already proves blank can only
+  // land on the hero, so hiding would blank the column for the whole
+  // history round-trip (the startup auto-selection flash) for nothing.
+  // The exemption is deliberately open-state-wide, not loading-only: a
+  // summary-blank session is the hero before its open starts (`cold`) and
+  // after one fails (`error`) for the same reason — there is no history.
  const settling = sessionId !== undefined && composerPhase === 'blank' && openState === 'loading'
-  const hero = sessionId === undefined || (composerPhase === 'blank' && openState === 'open')
+    && summaryBlank !== true
+  const hero = sessionId === undefined
+    || (composerPhase === 'blank' && (openState === 'open' || summaryBlank === true))
  const zone: InputZone | undefined =
    session === undefined || inputState === undefined ? undefined : { session, input: inputState }

--- a/packages/client/ui-conversation/tests/chat-view.spec.tsx
+++ b/packages/client/ui-conversation/tests/chat-view.spec.tsx
@@ -8,7 +8,7 @@ import { Profiler } from 'react'
 import { act, cleanup, fireEvent, render, within } from '@testing-library/react'
 import type {
  AssistantMessageNode, CommandNode, ConversationNode, ConversationSnapshot,
-  ModelRetryNode, RunningToolCall, SessionId, SessionListState, ToolResultNode,
+  ModelRetryNode, RunningToolCall, SessionId, SessionListState, ToolResultNode, TurnErrorNode,
  UserMessageNode, WorkspaceListState,
 } from '@deepseek-ai/dsh-client-runtime/client'
 import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
@@ -75,6 +75,11 @@ const retry = (seq: number): ModelRetryNode => ({
  retry: 1, maxRetries: 2, delayMs: 450,
  failure: { code: 'TRANSPORT', message: '连接被重置' },
 })
+const turnError = (seq: number, code?: string): TurnErrorNode => ({
+  kind: 'turn-error', seq, time: seq * 1_000, turn: 1, step: 0,
+  message: seq === 2 ? 'API key is invalid' : 'plugin exploded',
+  ...(code === undefined ? {} : { code }),
+})
 const toolResult = (seq: number, callId: string, name = 'bash'): ToolResultNode => ({
  kind: 'tool-result', seq, time: seq * 1_000, callId,
  call: { name, argsRaw: `{"command":"cmd-${callId}","description":"run ${callId}"}` },
@@ -295,6 +300,16 @@ describe('ChatView', () => {
    expect(within(cancelledDisclosure).getByRole('status').textContent).toContain('重试已取消')
  })

+  it('renders terminal turn failures inline with their durable message and optional code', () => {
+    const h = makeHarness({ nodes: [user(1, 'try'), turnError(2, 'AUTH'), turnError(3)] })
+    const view = render(<h.ChatView {...h.props} />)
+    const statuses = view.getAllByRole('status')
+    expect(statuses.map(status => status.textContent)).toEqual([
+      '本轮运行失败API key is invalidAUTH',
+      '本轮运行失败plugin exploded',
+    ])
+  })
+
  it('the expanded row Inspect pill hands the call id to inspectCall', () => {
    const h = makeHarness({
      nodes: [toolResult(3, 'a')],
--- a/packages/client/ui-conversation/tests/skeleton.spec.tsx
+++ b/packages/client/ui-conversation/tests/skeleton.spec.tsx
@@ -80,16 +80,25 @@ function mount(
  snapshot: ConversationSnapshot,
  workspaceRows: WorkspaceView[] = [{ ...workspace('one'), sessionIds: [SID] }],
  retargetWorkspace = vi.fn(async (_workspaceId: WorkspaceId) => {}),
-  /** When true, mimic overlay:true chain siblings (hidden fallback + takeover). */
-  overlayTakeover = false,
+  options: {
+    /** When true, mimic overlay:true chain siblings (hidden fallback + takeover). */
+    overlayTakeover?: boolean
+    /** The session list summary's `blank` flag — independent of the snapshot's. */
+    summaryBlank?: boolean
+    /** Drop the session's summary row entirely (a session the list has not caught up with). */
+    omitSummaryRow?: boolean
+  } = {},
 ) {
  const root = sid('root')
+  const rootRow = { id: root, displayTitle: 'Root', running: false, waitingApproval: false, blank: false, updatedAt: 1 }
+  const childRow = {
+    id: SID, displayTitle: 'Child', parentId: root, cwd: '/projects/one',
+    running: false, waitingApproval: false, blank: options.summaryBlank ?? false, updatedAt: 2,
+  }
+  const listed = options.omitSummaryRow !== true
  const sessions = createSnapshotStore<SessionListState>({
-    ids: [root, SID],
-    byId: {
-      [root]: { id: root, displayTitle: 'Root', running: false, waitingApproval: false, blank: false, updatedAt: 1 },
-      [SID]: { id: SID, displayTitle: 'Child', parentId: root, cwd: '/projects/one', running: false, waitingApproval: false, blank: false, updatedAt: 2 },
-    },
+    ids: listed ? [root, SID] : [root],
+    byId: { [root]: rootRow, ...listed && { [SID]: childRow } },
    current: SID,
    phase: 'ready',
  })
@@ -171,7 +180,7 @@ function mount(
    return <div data-testid={`view-${opts?.only ?? key}`} />
  }) as ConversationRootProps['renderSlot']
  const renderSlotChain = ((_key, _owner, opts) => (
-    overlayTakeover
+    options.overlayTakeover === true
      ? (
        <>
          <div data-chain-overlay-fallback="conversation.composer" style={{ display: 'none' }}>
@@ -233,7 +242,7 @@ describe('ConversationRoot resident composer', () => {
  })

  it('sticky composer seat wraps the whole overlay chain, not only the fallback stack', () => {
-    const b = mount(conversationSnapshot(), undefined, undefined, true)
+    const b = mount(conversationSnapshot(), undefined, undefined, { overlayTakeover: true })
    const seat = b.view.container.querySelector('[data-composer-seat]')
    const takeover = b.view.getByTestId('composer-takeover')
    const fallback = b.view.container.querySelector('[data-chain-overlay-fallback="conversation.composer"]')
@@ -274,6 +283,39 @@ describe('ConversationRoot resident composer', () => {
    expect(b.view.getByText('Selected Folder')).toBeTruthy()
  })

+  it('settling phase: a summary that does not prove the session blank hides the composer while it opens', () => {
+    const b = mount(conversationSnapshot({ composerPhase: 'blank', blank: true, openState: 'loading' }))
+    const root = b.view.container.querySelector('[data-phase]')
+    expect(root?.getAttribute('data-phase')).toBe('settling')
+    expect(b.view.queryByText('开始构建吧')).toBeNull()
+  })
+
+  it('settling phase: a session the list has no row for settles conservatively', () => {
+    const b = mount(
+      conversationSnapshot({ composerPhase: 'blank', blank: true, openState: 'loading' }),
+      undefined,
+      undefined,
+      { omitSummaryRow: true },
+    )
+    const root = b.view.container.querySelector('[data-phase]')
+    expect(root?.getAttribute('data-phase')).toBe('settling')
+  })
+
+  it('startup auto-selection: a summary-proven blank session opens straight into the hero', () => {
+    const b = mount(
+      conversationSnapshot({ composerPhase: 'blank', blank: true, openState: 'loading' }),
+      undefined,
+      undefined,
+      { summaryBlank: true },
+    )
+    // The summary already proves the outcome, so the settling hide would only
+    // blank the column for the history round-trip.
+    const root = b.view.container.querySelector('[data-phase]')
+    expect(root?.getAttribute('data-phase')).toBe('hero')
+    expect(b.view.getByText('开始构建吧')).toBeTruthy()
+    expect(b.view.getByRole('textbox')).toBeTruthy()
+  })
+
  it('same textarea DOM node survives the hero → active flip into the sticky scrollport', () => {
    const b = mount(conversationSnapshot({ composerPhase: 'blank', blank: true }))
    const before = b.view.getByRole('textbox')
--- a/packages/client/ui-trajectory/README.i18n.yaml
+++ b/packages/client/ui-trajectory/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/ui-trajectory/README.md
-README.md: b9c8b849b3454fe46e1fc37713d9d3b9449734cf
-README.zh.md: 6ddc32f2f27c93f8ccc80b3d9b31d56d3cf4dd94
+README.md: a65c11aed9dd74f9b0b60795441f876c1d64b3ad
+README.zh.md: 6e25d24c6b65673b3d003e624b6e0727be60c0e1
--- a/packages/client/ui-trajectory/README.md
+++ b/packages/client/ui-trajectory/README.md
@@ -2,7 +2,7 @@

 English | [中文](README.zh.md)

-Trajectory renders a turn-aware event ledger with selectable User, Assistant, Tool, and nested Subtool records. Thick rules mark Turn boundaries, compact inline markers identify Steps, and the main ledger keeps only index, event, and content; selection opens a local inspector for token usage, duration, Input, Output, and Timing. A fixed Overview above the ledger projects real record start/duration timing from left to right; dragging an interval focuses the ledger on every record active at any point in that inclusive range, while clearing the selection restores the full branch. The runtime's independent history source supplies raw context lineage and projects cancellation-frozen Assistant and Tool records, so Trajectory neither reads nor changes the Chat conversation snapshot. The package remains a pure-consumer plugin (registers one view tab into the conversation's `'conversation.view'` slot ring, provides no service, declares no Context merge). Contract: api-contracts v3 §8.
+Trajectory renders a turn-aware event ledger with selectable User, Assistant, Tool, and nested Subtool records. Thick rules mark Turn boundaries, compact inline markers identify Steps, and the main ledger keeps only index, event, and content; selection opens a local inspector for token usage, duration, Input, Output, and Timing. A standalone compaction request appears chronologically in its own `Between turns` section, while a numbered compaction remains inside its owning turn. A fixed Overview above the ledger projects real record start/duration timing from left to right; dragging an interval focuses the ledger on every record active at any point in that inclusive range, while clearing the selection restores the full branch. The runtime's independent history source supplies raw context lineage and projects cancellation-frozen Assistant and Tool records, so Trajectory neither reads nor changes the Chat conversation snapshot. The package remains a pure-consumer plugin (registers one view tab into the conversation's `'conversation.view'` slot ring, provides no service, declares no Context merge). Contract: api-contracts v3 §8.

 ## Model Experience

--- a/packages/client/ui-trajectory/README.zh.md
+++ b/packages/client/ui-trajectory/README.zh.md
@@ -2,7 +2,7 @@

 [English](README.md) | 中文

-Trajectory 渲染按轮次组织的事件记录表，其中可选择用户、助手、工具和嵌套子工具记录。较粗的分割线标示轮次边界，紧凑的行内标记标识步骤，主记录表仅保留索引、事件和内容；选择记录则会打开局部检查器，查看 token 用量、耗时、输入、输出和计时。固定在记录表上方的 Overview 区域从左到右投影记录的真实开始时间与耗时；拖选一个区间会将记录表聚焦到活动区间与该闭区间有重叠的所有记录，清除选择则恢复完整分支。运行时的独立历史数据源提供原始上下文谱系，并投影因取消而冻结的助手和工具记录，因此 Trajectory 既不读取也不改变 Chat 会话快照。该包（package）保持为纯消费方插件（向会话的 `'conversation.view'` slot 环注册一个视图标签页，不提供服务，也不声明 Context 合并）。契约：api-contracts v3 §8。
+Trajectory 渲染按轮次组织的事件记录表，其中可选择用户、助手、工具和嵌套子工具记录。较粗的分割线标示轮次边界，紧凑的行内标记标识步骤，主记录表仅保留索引、事件和内容；选择记录则会打开局部检查器，查看 token 用量、耗时、输入、输出和计时。独立运行的压缩（compaction）请求会按时间顺序显示在自己的 `Between turns` 区段中，而带数值所有者的压缩仍位于其所属轮次内。固定在记录表上方的 Overview 区域从左到右投影记录的真实开始时间与耗时；拖选一个区间会将记录表聚焦到活动区间与该闭区间有重叠的所有记录，清除选择则恢复完整分支。运行时的独立历史数据源提供原始上下文谱系，并投影因取消而冻结的助手和工具记录，因此 Trajectory 既不读取也不改变 Chat 会话快照。该包（package）保持为纯消费方插件（向会话的 `'conversation.view'` slot 环注册一个视图标签页，不提供服务，也不声明 Context 合并）。契约：api-contracts v3 §8。

 ## 模型体验

--- a/packages/client/ui-trajectory/src/client/TrajectoryTable.tsx
+++ b/packages/client/ui-trajectory/src/client/TrajectoryTable.tsx
@@ -104,7 +104,8 @@ const KIND_ICON: Record<TrajectoryCellKind, ReactNode> = {
 }

 interface TableRecord {
-  turn: number
+  turn: number | null
+  section: number
  group: string
  groupStart: boolean
  turnStart: boolean
@@ -146,7 +147,8 @@ interface ToolCallTextParts {
 }

 interface SelectedRequest {
-  turn: number
+  turn: number | null
+  section: number
  number: number
  group: string
 }
@@ -320,15 +322,12 @@ export interface TrajectoryTableProps {
  onInspectApplied?: (() => void) | undefined
 }

-/** One request identity paired with its session-global number. */
-export interface TrajectoryRequestNumber {
+/** Request-inspector fields shared by ordinary generation and compaction. */
+interface TrajectoryRequestNumberBase {
  /** Request anchor event sequence; absent for the currently streaming ordinary request. */
  seq?: number
-  turn: number
-  step: number
  group: string
  number: number
-  purpose?: 'compaction'
  status?: 'complete' | 'running' | 'error'
  startedAt?: number
  completedAt?: number | null
@@ -344,6 +343,20 @@ export interface TrajectoryRequestNumber {
  cumulativeUsage?: TrajectoryUsage
 }

+/** One purpose-discriminated request identity paired with its session-global number. */
+export type TrajectoryRequestNumber = TrajectoryRequestNumberBase & (
+  | {
+    purpose?: 'assistant'
+    turn: number
+    step: number
+  }
+  | {
+    purpose: 'compaction'
+    turn: number | null
+    step: 0
+  }
+)
+
 /** Disjoint provider token buckets for one request or a session prefix. */
 export interface TrajectoryUsage {
  input?: number
@@ -354,17 +367,18 @@ export interface TrajectoryUsage {
 }

 function flattenRecords(turns: readonly TrajectoryTurnModel[]): TableRecord[] {
-  return turns.flatMap((turn) => {
-    let firstInTurn = true
+  return turns.flatMap((turn, section) => {
+    let firstInSection = true
    const records = turn.groups.flatMap((group) => {
      return group.cells.map((cell, index) => {
-        const turnStart = firstInTurn
+        const turnStart = firstInSection
          && cell.requestOnly !== true
          && cell.kind !== 'system'
-          && cell.kind !== 'compacted'
-        if (turnStart) firstInTurn = false
+          && (cell.kind !== 'compacted' || turn.turn === null)
+        if (turnStart) firstInSection = false
        return {
          turn: turn.turn,
+          section,
          group: group.title,
          groupStart: index === 0,
          turnStart,
@@ -388,18 +402,18 @@ function filterRecords(
      record.cell.requestOnly !== true && matches.has(record.cell.index),
    )
    .map(record => ({ ...record, groupStart: false, turnStart: false, turnEnd: false }))
-  const startedTurns = new Set<number>()
+  const startedSections = new Set<number>()
  for (const [index, record] of filtered.entries()) {
    const previous = filtered[index - 1]
    const next = filtered[index + 1]
    record.groupStart = previous === undefined
-      || previous.turn !== record.turn
+      || previous.section !== record.section
      || previous.group !== record.group
-    record.turnStart = !startedTurns.has(record.turn)
+    record.turnStart = !startedSections.has(record.section)
      && record.cell.kind !== 'system'
-      && record.cell.kind !== 'compacted'
-    if (record.turnStart) startedTurns.add(record.turn)
-    record.turnEnd = next === undefined || next.turn !== record.turn
+      && (record.cell.kind !== 'compacted' || record.turn === null)
+    if (record.turnStart) startedSections.add(record.section)
+    record.turnEnd = next === undefined || next.section !== record.section
  }
  return filtered
 }
@@ -410,10 +424,14 @@ function requestStep(group: string): number | undefined {
  return Number.isInteger(value) && value > 0 ? value : undefined
 }

-function requestKey(turn: number, group: string): string {
+function requestKey(turn: number | null, group: string): string {
  return `${turn}\u0000${group}`
 }

+function sectionLabel(turn: number | null): string {
+  return turn === null ? 'Between turns' : `Turn ${turn}`
+}
+
 function indexRequestNumbers(
  records: readonly TableRecord[],
  sessionNumbers: readonly TrajectoryRequestNumber[] | undefined,
@@ -455,12 +473,13 @@ function collapseTurnRecords(
  if (collapsedTurns.size === 0) return [...records]
  const recordsByTurn = new Map<number, TableRecord[]>()
  for (const record of records) {
+    if (record.turn === null) continue
    const turnRecords = recordsByTurn.get(record.turn) ?? []
    turnRecords.push(record)
    recordsByTurn.set(record.turn, turnRecords)
  }
  return records.flatMap((record) => {
-    if (!collapsedTurns.has(record.turn)) return [record]
+    if (record.turn === null || !collapsedTurns.has(record.turn)) return [record]
    const turnRecords = recordsByTurn.get(record.turn) ?? [record]
    if (record.cell.requestOnly === true || record.cell.kind === 'system') return [record]
    const contentRecords = turnRecords.filter(candidate =>
@@ -1537,6 +1556,7 @@ export function TrajectoryTable({
    ? []
    : allRecords.filter(record =>
      record.turn === selectedRequest.turn
+        && record.section === selectedRequest.section
        && record.group === selectedRequest.group,
    )
  const selectedRequestAssistant = selectedRequestRecords.find(
@@ -1588,7 +1608,8 @@ export function TrajectoryTable({
  const selectedRequestCumulativeUsage =
    selectedRequestInfo?.cumulativeUsage ?? selectedRequestUsage
  const selectedRequestOptions = selectedRequestInfo?.requestConfig
-  const activeTurn = selectedRequest?.turn ?? selected?.turn
+  const activeTurn = selectedRequest === null ? selected?.turn : selectedRequest.turn
+  const activeSection = selectedRequest === null ? selected?.section : selectedRequest.section
  const selectedTabs = selectedRequest !== null
    ? REQUEST_TABS.filter(tab => tab.id !== 'options' || selectedRequestOptions !== undefined)
    : selected === undefined ? [] : detailTabs(selected)
@@ -1604,6 +1625,7 @@ export function TrajectoryTable({
    selected !== undefined && selectedAssistantRequest !== undefined
      ? {
        turn: selected.turn,
+        section: selected.section,
        number: selectedAssistantRequest,
        group: selected.group,
      }
@@ -1664,7 +1686,7 @@ export function TrajectoryTable({

  const openRecordSummary = (target: TableRecord) => {
    const targetAt = allRecords.findIndex(record => record.cell.index === target.cell.index)
-    if (collapsedTurns.has(target.turn)) onToggleTurn(target.turn)
+    if (target.turn !== null && collapsedTurns.has(target.turn)) onToggleTurn(target.turn)
    if (target.cell.kind === 'tool' || target.cell.kind === 'subtool') {
      for (let i = targetAt - 1; i >= 0; i--) {
        const candidate = allRecords[i]
@@ -1739,7 +1761,7 @@ export function TrajectoryTable({
                && record.cell.index === allRecords[0]?.cell.index
              const request = record.groupStart
                && !isCollapsedSummary
-                && !collapsedTurns.has(record.turn)
+                && (record.turn === null || !collapsedTurns.has(record.turn))
                ? requestNumbers.get(requestKey(record.turn, record.group))
                : undefined
              const requestInfo = request === undefined
@@ -1750,7 +1772,11 @@ export function TrajectoryTable({
                : `Request #${request}${requestInfo?.purpose === 'compaction' ? ' · Compaction' : ''}`
              const requestSelected = request !== undefined
                && selectedRequest?.turn === record.turn
+                && selectedRequest.section === record.section
                && selectedRequest.number === request
+              const sectionActive = record.turn === null
+                ? activeSection === record.section
+                : activeTurn === record.turn
              return (
                <tr
                  key={`${record.cell.index}:${record.collapsedSummaryKind ?? 'record'}`}
@@ -1780,13 +1806,14 @@ export function TrajectoryTable({
                    ? undefined
                    : isCollapsedSummary
                      ? () => {
-                        if (record.collapsedSummaryKind === 'turn') onToggleTurn(record.turn)
-                        else onToggleAssistant(record.cell.index)
+                        if (record.collapsedSummaryKind === 'turn' && record.turn !== null) {
+                          onToggleTurn(record.turn)
+                        } else onToggleAssistant(record.cell.index)
                      }
                      : () => { selectRecord(record.cell.index) }}
                  onDoubleClick={(event) => {
                    if (isCollapsedSummary || isRequestOnly) return
-                    if (collapsedTurns.has(record.turn)) {
+                    if (record.turn !== null && collapsedTurns.has(record.turn)) {
                      event.preventDefault()
                      onToggleTurn(record.turn)
                      return
@@ -1800,6 +1827,7 @@ export function TrajectoryTable({
                      return
                    }
                    if (!record.turnStart) return
+                    if (record.turn === null) return
                    if (allRecords.filter(candidate =>
                      candidate.turn === record.turn
                      && candidate.cell.requestOnly !== true
@@ -1812,8 +1840,9 @@ export function TrajectoryTable({
                    if (event.key !== 'Enter' && event.key !== ' ') return
                    event.preventDefault()
                    if (isCollapsedSummary) {
-                      if (record.collapsedSummaryKind === 'turn') onToggleTurn(record.turn)
-                      else onToggleAssistant(record.cell.index)
+                      if (record.collapsedSummaryKind === 'turn' && record.turn !== null) {
+                        onToggleTurn(record.turn)
+                      } else onToggleAssistant(record.cell.index)
                      return
                    }
                    selectRecord(record.cell.index)
@@ -1833,6 +1862,7 @@ export function TrajectoryTable({
                          event.stopPropagation()
                          selectRequest({
                            turn: record.turn,
+                            section: record.section,
                            number: request,
                            group: record.group,
                          })
@@ -1840,7 +1870,9 @@ export function TrajectoryTable({
                        onDoubleClick={(event) => { event.stopPropagation() }}
                      />
                    )}
-                    {activeTurn === record.turn && !isInitialSystem && (
+                    {record.turn !== null
+                    && activeTurn === record.turn
+                    && !isInitialSystem && (
                      <span className={css.turnRail} aria-hidden="true" />
                    )}
                    {!isCollapsedSummary && selectedIndex === record.cell.index && (
@@ -1850,17 +1882,23 @@ export function TrajectoryTable({
                    && !isRequestOnly
                    && record.turnStart && (
                      <span
-                        className={activeTurn === record.turn
+                        className={sectionActive
                          ? `${css.turnLabel} ${css.turnLabelActive}`
                          : css.turnLabel}
-                        aria-label={`Turn ${record.turn}`}
+                        aria-label={sectionLabel(record.turn)}
                      >
-                        <span className={css.turnLabelFull} aria-hidden="true">
-                          Turn {record.turn}
-                        </span>
-                        <span className={css.turnLabelCompact} aria-hidden="true">
-                          #{record.turn}
-                        </span>
+                        {record.turn === null
+                          ? sectionLabel(record.turn)
+                          : (
+                            <>
+                              <span className={css.turnLabelFull} aria-hidden="true">
+                                {sectionLabel(record.turn)}
+                              </span>
+                              <span className={css.turnLabelCompact} aria-hidden="true">
+                                #{record.turn}
+                              </span>
+                            </>
+                          )}
                      </span>
                    )}
                    <div className={css.eventInner}>
@@ -2049,8 +2087,8 @@ export function TrajectoryTable({
                    </span>
                    <span className={css.detailsLocation}>
                      {selectedRequestInfo?.purpose === 'compaction'
-                        ? `Compaction · Turn ${selectedRequest.turn}`
-                        : `Turn ${selectedRequest.turn}`}
+                        ? `Compaction · ${sectionLabel(selectedRequest.turn)}`
+                        : sectionLabel(selectedRequest.turn)}
                    </span>
                  </>
                )
@@ -2081,8 +2119,8 @@ export function TrajectoryTable({
                      </span>
                      <span className={css.detailsLocation}>
                        {selected.cell.kind === 'compacted'
-                          ? `Turn ${selected.turn}`
-                          : `Turn ${selected.turn} · ${selected.group}`}
+                          ? sectionLabel(selected.turn)
+                          : `${sectionLabel(selected.turn)} · ${selected.group}`}
                      </span>
                    </>
                  )}
--- a/packages/client/ui-trajectory/src/client/TrajectoryTimeline.tsx
+++ b/packages/client/ui-trajectory/src/client/TrajectoryTimeline.tsx
@@ -431,9 +431,9 @@ export const TrajectoryTimeline = memo(function TrajectoryTimeline({
            style={projectedDomainStyle}
          >
            {model.turnBoundaries
-              .slice(1)
              .filter(boundary =>
-                boundary.time >= domainStart
+                boundary.time > model.start
+                && boundary.time >= domainStart
                && boundary.time <= domainStart + domainDuration)
              .map(boundary => (
                <span
--- a/packages/client/ui-trajectory/src/client/TrajectoryView.tsx
+++ b/packages/client/ui-trajectory/src/client/TrajectoryView.tsx
@@ -102,7 +102,7 @@ function searchMatches(
          ...(cell.outputBlocks ?? []),
        ]
        const text = [
-          `turn ${turn.turn}`,
+          turn.turn === null ? 'between turns' : `turn ${turn.turn}`,
          group.title,
          cell.kind,
          cell.kind === 'message' ? 'assistant' : undefined,
@@ -383,13 +383,15 @@ export function TrajectoryView({
  const collapsibleTurnIds = useMemo(
    () => turns
      .filter(turn =>
+        turn.turn !== null
+        &&
        turn.groups.reduce(
          (count, group) =>
            count + group.cells.filter(cell =>
              cell.requestOnly !== true && cell.kind !== 'system').length,
          0,
        ) > 1)
-      .map(turn => turn.turn),
+      .flatMap(turn => turn.turn === null ? [] : [turn.turn]),
    [turns],
  )
  const allTurnsCollapsed = collapsibleTurnIds.length > 0
--- a/packages/client/ui-trajectory/src/client/context-branches.ts
+++ b/packages/client/ui-trajectory/src/client/context-branches.ts
@@ -107,6 +107,8 @@ export function trajectoryBranchContainsRequest(
    request.resultSeq !== undefined
    && branch.retainedSurfaceSeqs.has(request.resultSeq)
  ) || (
+    request.purpose === 'compaction'
+    &&
    request.replacementSeq !== undefined
    && branch.retainedSurfaceSeqs.has(request.replacementSeq)
  )
--- a/packages/client/ui-trajectory/src/client/layout.ts
+++ b/packages/client/ui-trajectory/src/client/layout.ts
@@ -25,9 +25,9 @@ export interface TrajectoryGroupModel {
  cells: readonly TrajectoryCellProps[]
 }

-/** One sticky-turn section. */
+/** One sticky turn, or a standalone compaction section between turns. */
 export interface TrajectoryTurnModel {
-  turn: number
+  turn: number | null
  groups: readonly TrajectoryGroupModel[]
 }

@@ -67,6 +67,9 @@ interface TurnBucket {
  groups: LaidGroup[]
 }

+type AssistantRequestView = Extract<RequestView, { purpose: 'assistant' }>
+type CompactionRequestView = Extract<RequestView, { purpose: 'compaction' }>
+
 const PREVIEW_SOURCE_CHARACTERS = 2_048
 const PREVIEW_OUTPUT_CHARACTERS = 512

@@ -85,18 +88,18 @@ type OrderedLayoutEntry =
  | {
    kind: 'compaction'
    seq: number
-    request: RequestView
+    request: CompactionRequestView
  }
  | {
    kind: 'system'
    seq: number
-    request: RequestView
+    request: AssistantRequestView
    change: RequestPromptChange
  }
  | {
    kind: 'request'
    seq: number
-    request: RequestView
+    request: AssistantRequestView
  }

 function layoutEntryOrder(entry: OrderedLayoutEntry): number {
@@ -141,6 +144,7 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
    if (startedAt !== null) callStartById.set(call.callId, startedAt)
  }
  const turns = new Map<number, TurnBucket>()
+  const standaloneCompactions: TurnBucket[] = []
  let index = 0
  let prevAbsTime: number | null = null
  let lastAssistantTurn: number | null = null
@@ -196,13 +200,16 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
      nodeIndex,
    })),
    ...requests
-      .filter(request => request.purpose === 'compaction')
+      .filter((request): request is CompactionRequestView =>
+        request.purpose === 'compaction')
      .map(request => ({
        kind: 'compaction' as const,
        seq: request.startSeq,
        request,
      })),
-    ...requests.flatMap(request => request.promptChange === undefined || request.prompt === undefined
+    ...requests.flatMap(request => request.purpose !== 'assistant'
+      || request.promptChange === undefined
+      || request.prompt === undefined
      ? []
      : [{
        kind: 'system' as const,
@@ -211,7 +218,8 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
        change: request.promptChange,
      }]),
    ...requests
-      .filter(request => request.purpose === 'assistant')
+      .filter((request): request is AssistantRequestView =>
+        request.purpose === 'assistant')
      .filter(request =>
        !representedRequests.has(`${request.turn}\u0000${request.step}`),
      )
@@ -302,13 +310,17 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
        startedAt: finiteTime(request.startedAt),
      }
      attachUsage(cell, request.usage as UsageLike | undefined)
-      bucket(request.turn).groups.push({
-        title: `Compaction ${request.startSeq}`,
-        laid: [{
-          absTime: finiteTime(request.startedAt),
-          cell,
+      const compaction: TurnBucket = {
+        groups: [{
+          title: `Compaction ${request.startSeq}`,
+          laid: [{
+            absTime: finiteTime(request.startedAt),
+            cell,
+          }],
        }],
-      })
+      }
+      if (request.turn === null) standaloneCompactions.push(compaction)
+      else bucket(request.turn).groups.push(...compaction.groups)
      prevAbsTime = finiteTime(request.completedAt) ?? finiteTime(request.startedAt) ?? prevAbsTime
      continue
    }
@@ -451,15 +463,16 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
    turns.set(1, first)
  }

-  for (const entry of turns.values()) {
+  for (const entry of [...turns.values(), ...standaloneCompactions]) {
    for (const group of entry.groups) {
      for (const laid of group.laid) attachToolSchema(laid, callSchemas)
    }
  }

-  return [...turns.entries()]
-    .sort(([a], [b]) => a - b)
-    .map(([turn, entry]) => toTurnModel(turn, entry))
+  return [
+    ...[...turns.entries()].map(([turn, entry]) => toTurnModel(turn, entry)),
+    ...standaloneCompactions.map(entry => toTurnModel(null, entry)),
+  ].sort((left, right) => firstCellIndex(left) - firstCellIndex(right))
 }

 function attachToolSchema(
@@ -473,7 +486,7 @@ function attachToolSchema(
 }

 function toTurnModel(
-  turn: number,
+  turn: number | null,
  entry: TurnBucket,
 ): TrajectoryTurnModel {
  const groups = entry.groups.map(({ title, laid }): TrajectoryGroupModel => {
@@ -487,6 +500,14 @@ function toTurnModel(
  return { turn, groups }
 }

+/** Chronological section position from the fold's monotonically assigned cell indexes. */
+function firstCellIndex(turn: TrajectoryTurnModel): number {
+  return Math.min(
+    ...turn.groups.flatMap(group => group.cells.map(cell => cell.index)),
+    Number.POSITIVE_INFINITY,
+  )
+}
+
 /** Wall-span duration + tool histogram, e.g. `1.5 s bash×6`. */
 function groupDescription(laid: readonly LaidCell[]): string | undefined {
  const parts: string[] = []
--- a/packages/client/ui-trajectory/src/client/timeline.ts
+++ b/packages/client/ui-trajectory/src/client/timeline.ts
@@ -87,10 +87,12 @@ export function deriveTrajectoryTimeline(
      group.cells.filter(cell => cell.requestOnly !== true),
    )
    if (cells.length === 0) continue
-    turnBoundaries.push({
-      turn: turn.turn,
-      time: spans.length,
-    })
+    if (turn.turn !== null) {
+      turnBoundaries.push({
+        turn: turn.turn,
+        time: spans.length,
+      })
+    }
    spans.push(...cells.map((cell, offset): TrajectoryTimelineSpan => ({
      start: spans.length + offset,
      end: spans.length + offset + 1,
@@ -150,10 +152,12 @@ function deriveTimedTimeline(
      start: span.start - removedUserIdle,
      end: (actualDuration ? span.end : span.start) - removedUserIdle,
    })))
-    turnBoundaries.push({
-      turn: turn.turn,
-      time: turnStart - removedUserIdle,
-    })
+    if (turn.turn !== null) {
+      turnBoundaries.push({
+        turn: turn.turn,
+        time: turnStart - removedUserIdle,
+      })
+    }
    previousTurnEnd = previousTurnEnd === null
      ? turnEnd
      : Math.max(previousTurnEnd, turnEnd)
--- a/packages/client/ui-trajectory/tests/context-branches.spec.ts
+++ b/packages/client/ui-trajectory/tests/context-branches.spec.ts
@@ -38,17 +38,22 @@ function request(
  resultSeq?: number,
  replacementSeq?: number,
 ): RequestView {
-  return {
-    purpose,
+  const base = {
    startSeq,
-    turn: 1,
-    step: purpose === 'assistant' ? 1 : 0,
    startedAt: startSeq,
    completedAt: startSeq + 1,
-    status: 'complete',
+    status: 'complete' as const,
    ...(resultSeq === undefined ? {} : { resultSeq }),
-    ...(replacementSeq === undefined ? {} : { replacementSeq }),
  }
+  return purpose === 'assistant'
+    ? { ...base, purpose, turn: 1, step: 1 }
+    : {
+      ...base,
+      purpose,
+      turn: 1,
+      step: 0,
+      ...(replacementSeq === undefined ? {} : { replacementSeq }),
+    }
 }

 describe('trajectory context branches', () => {
--- a/packages/client/ui-trajectory/tests/layout.spec.tsx
+++ b/packages/client/ui-trajectory/tests/layout.spec.tsx
@@ -5,7 +5,9 @@
 */
 import { afterEach, describe, expect, it } from 'vitest'
 import { cleanup, render, screen } from '@testing-library/react'
-import type { ConversationSnapshot } from '@deepseek-ai/dsh-client-runtime/client'
+import type {
+  ConversationSnapshot, RequestView,
+} from '@deepseek-ai/dsh-client-runtime/client'
 import { TrajectoryGroupHeader } from '../src/client/TrajectoryGroupHeader.tsx'
 import { TrajectoryTurn } from '../src/client/TrajectoryTurn.tsx'
 import { TrajectoryTurnHeader } from '../src/client/TrajectoryTurnHeader.tsx'
@@ -161,6 +163,49 @@ describe('deriveTrajectoryLayout', () => {
    expect(turns[1]?.groups.flatMap(g => g.cells.map(c => c.text))).toEqual(['second', 'ok2'])
  })

+  it('places standalone compaction chronologically in its own between-turn section', () => {
+    const nodes = [
+      { kind: 'user', seq: 1, time: 1_000, content: [{ type: 'text', text: 'first' }], source: null },
+      {
+        kind: 'assistant', seq: 2, time: 2_000, turn: 1, step: 1,
+        blocks: [{ kind: 'text', text: 'before compaction' }],
+      },
+      { kind: 'user', seq: 5, time: 5_000, content: [{ type: 'text', text: 'second' }], source: null },
+      {
+        kind: 'assistant', seq: 6, time: 6_000, turn: 2, step: 1,
+        blocks: [{ kind: 'text', text: 'after compaction' }],
+      },
+    ] as unknown as ConversationSnapshot['nodes']
+    const compaction: RequestView = {
+      purpose: 'compaction',
+      startSeq: 3,
+      turn: null,
+      step: 0,
+      startedAt: 3_000,
+      completedAt: 4_000,
+      status: 'complete',
+      summary: [{ type: 'text', text: 'standalone summary' }],
+    }
+
+    const turns = deriveTrajectoryLayout({
+      codeDispatches: new Map(),
+      nodes,
+      partial: null,
+      runningCalls: [],
+      requests: [compaction],
+    })
+
+    expect(turns.map(turn => turn.turn)).toEqual([1, null, 2])
+    expect(turns[1]?.groups).toMatchObject([{
+      title: 'Compaction 3',
+      cells: [{
+        kind: 'compacted',
+        sourceSeq: 3,
+        text: 'standalone summary',
+      }],
+    }])
+  })
+
  it('keeps usage and a meaningful summary when assistant has no text block', () => {
    const nodes = [
      {
--- a/packages/client/ui-trajectory/tests/views.spec.tsx
+++ b/packages/client/ui-trajectory/tests/views.spec.tsx
@@ -290,6 +290,105 @@ describe('tab switching in ConversationRoot', () => {
    expect(screen.queryByRole('complementary', { name: 'Event details' })).toBeNull()
  })

+  it('labels a standalone compaction as between-turn work in the ledger and inspector', async () => {
+    const nodes = [
+      { kind: 'user', seq: 1, time: 1_000, content: [], source: null },
+      {
+        kind: 'assistant', seq: 2, time: 2_000, turn: 1, step: 1,
+        blocks: [{ kind: 'text', text: 'before' }],
+      },
+      { kind: 'user', seq: 5, time: 5_000, content: [], source: null },
+      {
+        kind: 'assistant', seq: 6, time: 6_000, turn: 2, step: 1,
+        blocks: [{ kind: 'text', text: 'after' }],
+      },
+    ] as unknown as ConversationSnapshot['nodes']
+    const compaction: RequestView = {
+      purpose: 'compaction',
+      startSeq: 3,
+      turn: null,
+      step: 0,
+      startedAt: 3_000,
+      completedAt: 4_000,
+      status: 'complete',
+      summary: [{ type: 'text', text: 'standalone summary' }],
+    }
+    const b = await bench(historySnapshot(nodes, { requests: [compaction] }))
+    const view = mount(b.slots, nodes)
+    fireEvent.click(screen.getByRole('tab', { name: 'Trajectory' }))
+
+    expect(screen.getByText('Between turns')).toBeTruthy()
+    expect(view.container.textContent).not.toContain('Turn null')
+
+    fireEvent.click(screen.getByRole('button', { name: 'Request #2 · Compaction' }))
+    expect(screen.getByText('Compaction · Between turns')).toBeTruthy()
+    expect(view.container.textContent).not.toContain('Turn null')
+  })
+
+  it('activates only the selected standalone compaction section', async () => {
+    const nodes = [
+      { kind: 'user', seq: 1, time: 1_000, content: [], source: null },
+      {
+        kind: 'assistant', seq: 2, time: 2_000, turn: 1, step: 1,
+        blocks: [{ kind: 'text', text: 'before first compaction' }],
+      },
+      { kind: 'user', seq: 5, time: 5_000, content: [], source: null },
+      {
+        kind: 'assistant', seq: 6, time: 6_000, turn: 2, step: 1,
+        blocks: [{ kind: 'text', text: 'between compactions' }],
+      },
+      { kind: 'user', seq: 9, time: 9_000, content: [], source: null },
+      {
+        kind: 'assistant', seq: 10, time: 10_000, turn: 3, step: 1,
+        blocks: [{ kind: 'text', text: 'after second compaction' }],
+      },
+    ] as unknown as ConversationSnapshot['nodes']
+    const compactions: RequestView[] = [
+      {
+        purpose: 'compaction',
+        startSeq: 3,
+        turn: null,
+        step: 0,
+        startedAt: 3_000,
+        completedAt: 4_000,
+        status: 'complete',
+        summary: [{ type: 'text', text: 'first standalone summary' }],
+      },
+      {
+        purpose: 'compaction',
+        startSeq: 7,
+        turn: null,
+        step: 0,
+        startedAt: 7_000,
+        completedAt: 8_000,
+        status: 'complete',
+        summary: [{ type: 'text', text: 'second standalone summary' }],
+      },
+    ]
+    const b = await bench(historySnapshot(nodes, { requests: compactions }))
+    mount(b.slots, nodes)
+    fireEvent.click(screen.getByRole('tab', { name: 'Trajectory' }))
+
+    const firstRequest = screen.getByRole('button', { name: 'Request #2 · Compaction' })
+    const secondRequest = screen.getByRole('button', { name: 'Request #4 · Compaction' })
+    const firstSection = firstRequest.closest('tr')?.querySelector('span')
+    const secondSection = secondRequest.closest('tr')?.querySelector('span')
+    expect(firstSection?.textContent).toBe('Between turns')
+    expect(secondSection?.textContent).toBe('Between turns')
+
+    fireEvent.click(firstRequest)
+    expect(firstSection?.className).toMatch(/turnLabelActive/)
+    expect(secondSection?.className).not.toMatch(/turnLabelActive/)
+    expect(screen.getByText('Request #2')).toBeTruthy()
+    expect(screen.getByText('Compaction · Between turns')).toBeTruthy()
+
+    fireEvent.click(secondRequest)
+    expect(firstSection?.className).not.toMatch(/turnLabelActive/)
+    expect(secondSection?.className).toMatch(/turnLabelActive/)
+    expect(screen.getByText('Request #4')).toBeTruthy()
+    expect(screen.getByText('Compaction · Between turns')).toBeTruthy()
+  })
+
  it('dragging the overview focuses overlapping records without filtering the ledger', async () => {
    const b = await bench()
    mount(b.slots)
@@ -563,6 +662,44 @@ describe('timeline projection', () => {
    })
  })

+  it('projects between-turn compaction without inventing a turn boundary', () => {
+    const withStandaloneCompaction = [
+      {
+        turn: 1,
+        groups: [{
+          title: 'Step 1',
+          cells: [{ index: 1, kind: 'message', text: 'before', timeSeconds: 0 }],
+        }],
+      },
+      {
+        turn: null,
+        groups: [{
+          title: 'Compaction 3',
+          cells: [{ index: 2, kind: 'compacted', text: 'summary', timeSeconds: 0 }],
+        }],
+      },
+      {
+        turn: 2,
+        groups: [{
+          title: 'Step 1',
+          cells: [{ index: 3, kind: 'message', text: 'after', timeSeconds: 0 }],
+        }],
+      },
+    ] satisfies readonly TrajectoryTurnModel[]
+
+    expect(deriveTrajectoryTimeline(withStandaloneCompaction)).toMatchObject({
+      spans: [
+        { index: 1, start: 0, end: 1 },
+        { index: 2, start: 1, end: 2 },
+        { index: 3, start: 2, end: 3 },
+      ],
+      turnBoundaries: [
+        { turn: 1, time: 0 },
+        { turn: 2, time: 2 },
+      ],
+    })
+  })
+
  it('empty inputs produce no model and the standalone view reports its empty form', () => {
    expect(deriveTrajectoryTimeline([])).toBeNull()
    render(createElement(