diff --git a/apps/cli/tests/github-webhook-real.e2e.ts b/apps/cli/tests/github-webhook-real.e2e.ts
index b02a9a1f54..ecec861d30 100644
--- a/apps/cli/tests/github-webhook-real.e2e.ts
+++ b/apps/cli/tests/github-webhook-real.e2e.ts
@@ -60,7 +60,10 @@ interface WorkspaceBaseline {
 }
 
 interface HistoryPage {
-  records: Array<{ event: HistoryEvent } | { chunks: unknown }>
+  records: Array<
+    | { type: 'event'; event: HistoryEvent }
+    | { type: 'chunks'; event: HistoryChunkEvent }
+  >
   hasMore: boolean
 }
 
@@ -69,6 +72,11 @@ interface HistoryEvent {
   data: unknown
 }
 
+interface HistoryChunkEvent extends HistoryEvent {
+  seq: number
+  time: number
+}
+
 interface ProcessObservation {
   readonly ready: Promise<string>
   readonly text: () => string
@@ -308,7 +316,14 @@ function assistantText(page: HistoryPage): string {
 
 /** Expand lossless history records for assertions over the public event stream. */
 function historyEvents(page: HistoryPage): HistoryEvent[] {
-  return page.records.flatMap(record => 'event' in record ? [record.event] : decodeStorageRecord(record.chunks))
+  return page.records.flatMap(record => record.type === 'event'
+    ? [record.event]
+    : decodeStorageRecord({
+      type: record.event.type.replace(/^chunkrow\//u, ''),
+      seq0: record.event.seq,
+      time0: record.event.time,
+      data: record.event.data,
+    }))
 }
 
 /** Stop the spawned CLI through its normal signal path, escalating only on a stuck teardown. */
diff --git a/apps/web/tests/smoke-real.e2e.ts b/apps/web/tests/smoke-real.e2e.ts
index c683c747fe..a5c5de075f 100644
--- a/apps/web/tests/smoke-real.e2e.ts
+++ b/apps/web/tests/smoke-real.e2e.ts
@@ -180,7 +180,10 @@ async function sessionCursor(baseUrl: string, sessionId: string): Promise<number
 }
 
 interface HistoryPage {
-  records: ({ event: HistoryEvent } | { chunks: unknown })[]
+  records: (
+    | { type: 'event'; event: HistoryEvent }
+    | { type: 'chunks'; event: HistoryEvent }
+  )[]
   hasMore: boolean
 }
 
@@ -194,7 +197,7 @@ function isRecord(value: unknown): value is Record<string, unknown> {
 }
 
 function providerTitle(page: HistoryPage): string | undefined {
-  const events = page.records.flatMap(record => 'event' in record ? [record.event] : [])
+  const events = page.records.flatMap(record => record.type === 'event' ? [record.event] : [])
   for (let index = events.length - 1; index >= 0; index--) {
     const event = events[index] as HistoryEvent
     if (event.type !== 'session/title' || !isRecord(event.data)) continue
@@ -208,7 +211,7 @@ function providerTitle(page: HistoryPage): string | undefined {
 
 function hasAssistantMarker(page: HistoryPage, marker: string): boolean {
   return page.records.some((record) => {
-    if (!('event' in record)) return false
+    if (record.type !== 'event') return false
     const { event } = record
     if (event.type !== 'assistant/message' || !isRecord(event.data) || !isRecord(event.data.message)) return false
     const content = event.data.message.content
@@ -564,9 +567,11 @@ describe('dsh web keyless CLI smoke', () => {
         return hasAssistantMarker(page, recoveredMarker)
       }, { timeout: 20_000 }).toBe(true)
       if (page === undefined) throw new Error('retry history was not observed')
-      const retry = page.records.find(record => 'event' in record && record.event.type === 'llm/retry')
+      const retry = page.records.find(record => (
+        record.type === 'event' && record.event.type === 'llm/retry'
+      ))
       expect(mainAttempts).toBe(2)
-      expect(retry !== undefined && 'event' in retry ? retry.event.data : undefined).toMatchObject({
+      expect(retry?.type === 'event' ? retry.event.data : undefined).toMatchObject({
         turn: 1,
         step: 1,
         retry: 1,
diff --git a/docs/event-producer-consumer.i18n.yaml b/docs/event-producer-consumer.i18n.yaml
index 934d20fd94..6bb9160f9b 100644
--- a/docs/event-producer-consumer.i18n.yaml
+++ b/docs/event-producer-consumer.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 docs/event-producer-consumer.md
-event-producer-consumer.md: ce914f90821adc09c59dca15f202831a51655565
-event-producer-consumer.zh.md: ca375c98b6c0552f255e5d2604c9ad0c1d968aad
+event-producer-consumer.md: b38d919b0586a116e163d8be3eb2c33fcfc6d67d
+event-producer-consumer.zh.md: fd36b3ebf40d5467f4b0849d972a7925838dee65
diff --git a/docs/event-producer-consumer.md b/docs/event-producer-consumer.md
index ce914f9082..b38d919b05 100644
--- a/docs/event-producer-consumer.md
+++ b/docs/event-producer-consumer.md
@@ -21,11 +21,11 @@ This matrix shows which packages dispatch each harness-owned event and which pac
 | `agent/session-start` | `emit` | [`packages/core/agent/src/runtime-types.ts:224`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `agent-team`, [`goal`](../packages/goal/goal), [`goal-round-driver`](../packages/goal/goal-round-driver), [`hooks-claude-code`](../packages/hooks/hooks-claude-code), [`hooks-codex`](../packages/hooks/hooks-codex) |
 | `agent/status` | `emit` | [`packages/core/agent/src/runtime-types.ts:185`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), `agent-team`, [`compaction-basic`](../packages/compaction/compaction-basic), [`goal-round-driver`](../packages/goal/goal-round-driver), [`schedule`](../packages/schedule/schedule), `server`, `session-controller` |
 | `agent/turn-stopping` | `serial` | [`packages/core/agent/src/runtime-types.ts:285`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`hooks-claude-code`](../packages/hooks/hooks-claude-code), [`hooks-codex`](../packages/hooks/hooks-codex) |
-| `api-session/activity` | `emit` | [`packages/api/session-controller/src/types.ts:491`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/added` | `emit` | [`packages/api/session-controller/src/types.ts:471`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/error` | `emit` | [`packages/api/session-controller/src/types.ts:498`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/removed` | `emit` | [`packages/api/session-controller/src/types.ts:477`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/status` | `emit` | [`packages/api/session-controller/src/types.ts:484`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/activity` | `emit` | [`packages/api/session-controller/src/types.ts:503`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/added` | `emit` | [`packages/api/session-controller/src/types.ts:483`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/error` | `emit` | [`packages/api/session-controller/src/types.ts:510`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/removed` | `emit` | [`packages/api/session-controller/src/types.ts:489`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/status` | `emit` | [`packages/api/session-controller/src/types.ts:496`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
 | `approval/request` | `waterfall` | [`packages/interaction/user-approval/src/types.ts:85`](../packages/interaction/user-approval/src/types.ts) | [`user-approval`](../packages/interaction/user-approval) (`waterfall`) | [`acp`](../packages/acp/acp), `remotes` |
 | `authorization/settled` | `emit` | [`packages/credentials/authorization/src/index.ts:57`](../packages/credentials/authorization/src/index.ts) | [`authorization`](../packages/credentials/authorization) (`events.dispatch`) | [`authorization`](../packages/credentials/authorization) |
 | `commands/change` | `emit` | [`packages/interaction/commands/src/types.ts:80`](../packages/interaction/commands/src/types.ts) | [`commands`](../packages/interaction/commands) (`events.dispatch`) | `remotes` |
diff --git a/docs/event-producer-consumer.zh.md b/docs/event-producer-consumer.zh.md
index ca375c98b6..fd36b3ebf4 100644
--- a/docs/event-producer-consumer.zh.md
+++ b/docs/event-producer-consumer.zh.md
@@ -23,11 +23,11 @@
 | `agent/session-start` | `emit` | [`packages/core/agent/src/runtime-types.ts:224`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emitAgentEvent`) | `agent-team`, [`goal`](../packages/goal/goal), [`goal-round-driver`](../packages/goal/goal-round-driver), [`hooks-claude-code`](../packages/hooks/hooks-claude-code), [`hooks-codex`](../packages/hooks/hooks-codex) |
 | `agent/status` | `emit` | [`packages/core/agent/src/runtime-types.ts:185`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`agent`](../packages/core/agent), `agent-team`, [`compaction-basic`](../packages/compaction/compaction-basic), [`goal-round-driver`](../packages/goal/goal-round-driver), [`schedule`](../packages/schedule/schedule), `server`, `session-controller` |
 | `agent/turn-stopping` | `serial` | [`packages/core/agent/src/runtime-types.ts:285`](../packages/core/agent/src/runtime-types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`hooks-claude-code`](../packages/hooks/hooks-claude-code), [`hooks-codex`](../packages/hooks/hooks-codex) |
-| `api-session/activity` | `emit` | [`packages/api/session-controller/src/types.ts:482`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/added` | `emit` | [`packages/api/session-controller/src/types.ts:462`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/error` | `emit` | [`packages/api/session-controller/src/types.ts:489`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/removed` | `emit` | [`packages/api/session-controller/src/types.ts:468`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
-| `api-session/status` | `emit` | [`packages/api/session-controller/src/types.ts:475`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/activity` | `emit` | [`packages/api/session-controller/src/types.ts:503`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/added` | `emit` | [`packages/api/session-controller/src/types.ts:483`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/error` | `emit` | [`packages/api/session-controller/src/types.ts:510`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/removed` | `emit` | [`packages/api/session-controller/src/types.ts:489`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
+| `api-session/status` | `emit` | [`packages/api/session-controller/src/types.ts:496`](../packages/api/session-controller/src/types.ts) | `session-controller` (`emit`) | `remotes` |
 | `approval/request` | `waterfall` | [`packages/interaction/user-approval/src/types.ts:85`](../packages/interaction/user-approval/src/types.ts) | [`user-approval`](../packages/interaction/user-approval) (`waterfall`) | [`acp`](../packages/acp/acp), `remotes` |
 | `authorization/settled` | `emit` | [`packages/credentials/authorization/src/index.ts:57`](../packages/credentials/authorization/src/index.ts) | [`authorization`](../packages/credentials/authorization) (`events.dispatch`) | [`authorization`](../packages/credentials/authorization) |
 | `commands/change` | `emit` | [`packages/interaction/commands/src/types.ts:80`](../packages/interaction/commands/src/types.ts) | [`commands`](../packages/interaction/commands) (`events.dispatch`) | `remotes` |
diff --git a/packages/api/session-controller/README.i18n.yaml b/packages/api/session-controller/README.i18n.yaml
index 672f8a1599..d417370290 100644
--- a/packages/api/session-controller/README.i18n.yaml
+++ b/packages/api/session-controller/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/api/session-controller/README.md
-README.md: 24df6e1e367eb76e942087065cf9a29a34e94127
-README.zh.md: 710912be75195567b557c7dc103cabb7eed1e80f
+README.md: 510f336c76dd80ed01bdd2bd4a364106f418831f
+README.zh.md: 4503a8f9d0bcfc7f669f00cbc4db69e0d3efd3cd
diff --git a/packages/api/session-controller/README.md b/packages/api/session-controller/README.md
index 24df6e1e36..510f336c76 100644
--- a/packages/api/session-controller/README.md
+++ b/packages/api/session-controller/README.md
@@ -4,11 +4,11 @@ English | [中文](README.zh.md)
 
 `@deepseek-ai/dsh-api-session-controller` owns the Host `ctx.sessionController` service and the generated Client `ctx.remote.session` namespace. It serves Session list, search, creation, model selection, rename, fork, prompt, attachment, queue, cancellation, message-aligned history, live log following, and Host-wide control state.
 
-History pages carry `records`: ordinary records contain a raw `SessionWireEvent`, while consecutive same-block `assistant/chunk` deltas use the Session package's lossless packed-row encoding. `SessionEventStream` expands packed rows member-for-member before publishing a page to the Client Session object layer, so replay still observes every original event and sequence number. Follow frames remain raw individual events. Tool arguments, result content, failures, and `tool/result.data.meta` pass through unchanged; the controller does not resolve a Tool definition, run a presenter, or attach UI data.
+History pages and follow opening snapshots carry a discriminated `SessionHistoryRecord`. Both variants use `{ type, event }`: `type: 'event'` carries one raw `SessionWireEvent`, while `type: 'chunks'` carries one lossless `ChunkRowEvent` for consecutive same-block `assistant/chunk` deltas. Both inner values expose `type`, `seq`, `time`, and `data`, so the Client retains each accepted record as one `SessionEventLikeEntry` without record-by-record conversion. A packed event's `seq` and `time` identify its first member, and `data` retains the fragment and timestamp-gap arrays. Live follow frames remain individual `event` records. Tool arguments, result content, failures, and `tool/result.data.meta` pass through unchanged; the controller does not resolve a Tool definition, run a presenter, or attach UI data.
 
 Each endpoint states its activation policy. List, search, attachment, history pages, and log following can inspect persistence without activating an Agent; queue mutation and cancellation require the corresponding live state; model, rename, and prompt commands may explicitly resume an ordinary Session. Create and fork are the only operations that create a new Agent. The service applies one preset-aware resume policy and subagent ownership fence to its own methods and to the Typert Agent and Session lookups used by other Remote namespaces.
 
-The Client adapter exposes `SessionEventStream`, a Gateway `RemoteJournalStream` bound to one ordinary or direct-subagent address. It opens follow before the initial page, publishes only contiguous `replace`, `prepend`, and `append` changes, and repairs reconnect or sequence gaps through a tail page. A business, persistence, or unresolved continuity failure terminates the stream, while only physical carrier loss selects automatic resumption. `SessionControlStream` is a Gateway `RemoteSnapshotStream`; every generation opens with a complete process-local baseline, so reconnect replaces queue, jobs, and projection state instead of treating transient values as durable events.
+The Client adapter exposes `SessionEventStream`, a Gateway `RemoteJournalStream` bound to one ordinary or direct-subagent address. It opens follow before the initial page, publishes only contiguous `replace`, `prepend`, and `append` changes, and repairs reconnect or sequence gaps through a tail page. Ordinary records cover `[event.seq, event.seq]`; packed rows cover `[event.seq, event.seq + memberCount - 1]`. A business, persistence, or unresolved continuity failure terminates the stream, while only physical carrier loss selects automatic resumption. `SessionControlStream` is a Gateway `RemoteSnapshotStream`; every generation opens with a complete process-local baseline, so reconnect replaces queue, jobs, and projection state instead of treating transient values as durable events.
 
 ## Model Experience
 
diff --git a/packages/api/session-controller/README.zh.md b/packages/api/session-controller/README.zh.md
index 710912be75..4503a8f9d0 100644
--- a/packages/api/session-controller/README.zh.md
+++ b/packages/api/session-controller/README.zh.md
@@ -4,11 +4,11 @@
 
 `@deepseek-ai/dsh-api-session-controller` 拥有 Host 的 `ctx.sessionController` 服务和生成的 Client `ctx.remote.session` namespace。它提供 Session 列表、搜索、创建、模型选择、重命名、fork、prompt、附件、queue、取消、按消息对齐的历史、live 日志跟随和 Host 范围 control 状态。
 
-历史页携带 `records`：普通记录包含原始 `SessionWireEvent`，连续且属于同一 block 的 `assistant/chunk` delta 使用 Session 包的无损打包行编码。`SessionEventStream` 会在向 Client Session 对象层发布页面前逐成员展开打包行，因此回放仍能观察到每个原始事件和序号。Follow frame 继续携带单个原始事件。工具参数、结果内容、失败信息和 `tool/result.data.meta` 原样通过；controller 不解析 Tool definition、不运行 presenter，也不附加 UI 数据。
+历史页与 follow opening snapshot 携带带判别字段的 `SessionHistoryRecord`。两个分支都使用 `{ type, event }`：`type: 'event'` 携带一个原始 `SessionWireEvent`，`type: 'chunks'` 则携带一个由连续且属于同一 block 的 `assistant/chunk` delta 组成的无损 `ChunkRowEvent`。两种内部值都公开 `type`、`seq`、`time` 与 `data`，因此 Client 无需逐 record 转换，就能把每条已接受 record 保留为一个 `SessionEventLikeEntry`。packed event 的 `seq` 与 `time` 表示首成员，`data` 保留 fragment 与 timestamp-gap 数组。实时 follow frame 继续携带单个 `event` record。工具参数、结果内容、失败信息和 `tool/result.data.meta` 原样通过；controller 不解析 Tool definition、不运行 presenter，也不附加 UI 数据。
 
 每个 endpoint 都声明自己的激活策略。列表、搜索、附件、历史页和日志跟随可以在不激活 Agent 的情况下检查 persistence；queue 变更和取消要求对应 live 状态仍然存在；模型、重命名和 prompt 命令可以显式恢复普通 Session。只有 create 和 fork 会创建新 Agent。该服务把同一套感知 preset 的恢复策略和 subagent ownership fence 同时用于自身方法，以及其他 Remote namespace 使用的 Typert Agent 与 Session lookup。
 
-Client adapter 提供 `SessionEventStream`，即绑定到一个普通 Session 或 direct subagent address 的 Gateway `RemoteJournalStream`。它在读取首个 page 前打开 follow，只发布连续的 `replace`、`prepend` 和 `append` 变更，并通过 tail page 修复重连或 seq 缺口。业务、persistence 或无法恢复的连续性错误会终止 stream，只有物理载体断开才触发自动恢复。`SessionControlStream` 是 Gateway `RemoteSnapshotStream`；每代都以完整的进程本地 baseline 开始，因此重连会替换 queue、jobs 和 projection 状态，而不会把瞬态值当作 durable event。
+Client adapter 提供 `SessionEventStream`，即绑定到一个普通 Session 或 direct subagent address 的 Gateway `RemoteJournalStream`。它在读取首个 page 前打开 follow，只发布连续的 `replace`、`prepend` 和 `append` 变更，并通过 tail page 修复重连或 seq 缺口。普通 record 覆盖 `[event.seq, event.seq]`，packed row 覆盖 `[event.seq, event.seq + memberCount - 1]`。业务、persistence 或无法恢复的连续性错误会终止 stream，只有物理载体断开才触发自动恢复。`SessionControlStream` 是 Gateway `RemoteSnapshotStream`；每代都以完整的进程本地 baseline 开始，因此重连会替换 queue、jobs 和 projection 状态，而不会把瞬态值当作 durable event。
 
 ## 模型体验
 
diff --git a/packages/api/session-controller/src/client/contract/events.ts b/packages/api/session-controller/src/client/contract/events.ts
index 2f8bc48f82..39ce09ccab 100644
--- a/packages/api/session-controller/src/client/contract/events.ts
+++ b/packages/api/session-controller/src/client/contract/events.ts
@@ -1,10 +1,22 @@
 /** Observable contiguous Session event window consumed by domain assemblers. */
 import { notifySubscribers, type ObservableSnapshot } from '@deepseek-ai/dsh-client-store'
-import type { SessionEventEntry } from '../../types.ts'
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+import type { ChunkRowEvent } from '../../types.ts'
+
+/** Standard Session event or compact historical Assistant run. */
+export type SessionEventLike = SessionEvent | ChunkRowEvent
+
+/** Client history entry retaining its coarse transport discriminator. */
+export type SessionEventLikeEntry =
+  | { readonly type: 'event'; readonly event: SessionEvent }
+  | { readonly type: 'chunks'; readonly event: ChunkRowEvent }
+
+/** Scalar live entry accepted by append-only Client paths. */
+export type SessionLiveEventEntry = Extract<SessionEventLikeEntry, { readonly type: 'event' }>
 
 interface EventWindowLeaf {
   readonly kind: 'leaf'
-  readonly entries: readonly SessionEventEntry[]
+  readonly entries: readonly SessionEventLikeEntry[]
   readonly length: number
 }
 
@@ -17,7 +29,7 @@ interface EventWindowConcat {
 
 type EventWindowNode = EventWindowLeaf | EventWindowConcat
 
-function leaf(entries: readonly SessionEventEntry[]): EventWindowLeaf {
+function leaf(entries: readonly SessionEventLikeEntry[]): EventWindowLeaf {
   return { kind: 'leaf', entries, length: entries.length }
 }
 
@@ -25,9 +37,9 @@ function concat(left: EventWindowNode, right: EventWindowNode): EventWindowConca
   return { kind: 'concat', left, right, length: left.length + right.length }
 }
 
-function materialize(node: EventWindowNode): readonly SessionEventEntry[] {
+function materialize(node: EventWindowNode): readonly SessionEventLikeEntry[] {
   if (node.kind === 'leaf') return node.entries
-  const entries = new Array<SessionEventEntry>(node.length)
+  const entries = new Array<SessionEventLikeEntry>(node.length)
   const pending: EventWindowNode[] = [node]
   let index = 0
   while (pending.length > 0) {
@@ -50,7 +62,7 @@ function windowSnapshot(
   revision: number,
   change: SessionEventChange,
 ): SessionEventWindow {
-  let entries: readonly SessionEventEntry[] | undefined
+  let entries: readonly SessionEventLikeEntry[] | undefined
   return {
     get entries() {
       entries ??= materialize(node)
@@ -64,13 +76,13 @@ function windowSnapshot(
 
 /** Exact delta that produced the latest event-window revision. */
 export type SessionEventChange =
-  | { readonly kind: 'replace'; readonly entries: readonly SessionEventEntry[] }
-  | { readonly kind: 'prepend'; readonly entries: readonly SessionEventEntry[] }
-  | { readonly kind: 'append'; readonly entries: readonly SessionEventEntry[] }
+  | { readonly kind: 'replace'; readonly entries: readonly SessionEventLikeEntry[] }
+  | { readonly kind: 'prepend'; readonly entries: readonly SessionEventLikeEntry[] }
+  | { readonly kind: 'append'; readonly entries: readonly SessionLiveEventEntry[] }
 
 /** Current contiguous event window and its latest synchronous delta. */
 export interface SessionEventWindow {
-  readonly entries: readonly SessionEventEntry[]
+  readonly entries: readonly SessionEventLikeEntry[]
   readonly hasMore: boolean
   readonly revision: number
   readonly change: SessionEventChange
@@ -108,7 +120,7 @@ export class MutableSessionEventSource implements SessionEventSource {
    * @param entries - complete window.
    * @param hasMore - whether older history remains.
    */
-  replace(entries: readonly SessionEventEntry[], hasMore: boolean): void {
+  replace(entries: readonly SessionEventLikeEntry[], hasMore: boolean): void {
     this.window = leaf(entries)
     this.publish(hasMore, { kind: 'replace', entries })
   }
@@ -118,7 +130,7 @@ export class MutableSessionEventSource implements SessionEventSource {
    * @param entries - newly loaded older entries.
    * @param hasMore - whether still older history remains.
    */
-  prepend(entries: readonly SessionEventEntry[], hasMore: boolean): void {
+  prepend(entries: readonly SessionEventLikeEntry[], hasMore: boolean): void {
     this.window = concat(leaf(entries), this.window)
     this.publish(hasMore, { kind: 'prepend', entries })
   }
@@ -127,7 +139,7 @@ export class MutableSessionEventSource implements SessionEventSource {
    * Append one contiguous live entry.
    * @param entry - live tail entry.
    */
-  append(entry: SessionEventEntry): void {
+  append(entry: SessionLiveEventEntry): void {
     const entries = [entry]
     this.window = concat(this.window, leaf(entries))
     this.publish(this.snapshot.hasMore, {
diff --git a/packages/api/session-controller/src/client/index.ts b/packages/api/session-controller/src/client/index.ts
index 86735be6ea..7fa6ede0d0 100644
--- a/packages/api/session-controller/src/client/index.ts
+++ b/packages/api/session-controller/src/client/index.ts
@@ -43,7 +43,14 @@ export type {
 export type { ISession, ProjectionsFace, SessionFace } from './contract/session.ts'
 export type { ISessions } from './contract/sessions.ts'
 export { MutableSessionEventSource } from './contract/events.ts'
-export type { SessionEventChange, SessionEventSource, SessionEventWindow } from './contract/events.ts'
+export type {
+  SessionEventChange,
+  SessionEventLike,
+  SessionEventLikeEntry,
+  SessionEventSource,
+  SessionEventWindow,
+  SessionLiveEventEntry,
+} from './contract/events.ts'
 export type {
   OpenState,
   PromptError,
diff --git a/packages/api/session-controller/src/client/sessions/history-records.ts b/packages/api/session-controller/src/client/sessions/history-records.ts
index 6058e7fc7e..77ed4ad980 100644
--- a/packages/api/session-controller/src/client/sessions/history-records.ts
+++ b/packages/api/session-controller/src/client/sessions/history-records.ts
@@ -1,21 +1,39 @@
-/** Lossless client decoding for packed Assistant delta runs in history responses. */
+/** Client range access and type narrowing for aligned Session history records. */
 
-import { decodeStorageRecord } from '@deepseek-ai/dsh-session/chunk-rows'
 import type {
-  SessionEventEntry,
   SessionHistoryRecord,
-  SessionWireEvent,
 } from '../../types.ts'
+import type { SessionEventLikeEntry } from '../contract/events.ts'
 
 /**
- * Convert history wire records into exact event inputs for Conversation Definitions.
- * @param records - validated lossless history transport records.
- * @returns Ordinary entries unchanged and packed runs expanded member-for-member.
+ * Narrow aligned wire records to their Client event types without allocation.
+ * @param records - validated history transport records.
+ * @returns the same record array with typed inner events.
  */
-export function historyEntries(records: readonly SessionHistoryRecord[]): SessionEventEntry[] {
-  return records.flatMap(record => 'event' in record
-    ? [record]
-    : decodeStorageRecord(record.chunks).map(event => ({
-      event: event as unknown as SessionWireEvent,
-    })))
+export function historyEntries(
+  records: readonly SessionHistoryRecord[],
+): readonly SessionEventLikeEntry[] {
+  return records as unknown as readonly SessionEventLikeEntry[]
+}
+
+/**
+ * Read the first logical sequence represented by one wire record.
+ * @param record - validated scalar event or packed Assistant delta run.
+ * @returns inclusive first Session sequence.
+ */
+export function historyRecordFirstSeq(record: SessionHistoryRecord): number {
+  return record.event.seq
+}
+
+/**
+ * Read the final logical sequence represented by one wire record.
+ * @param record - validated scalar event or packed Assistant delta run.
+ * @returns inclusive final Session sequence.
+ */
+export function historyRecordLastSeq(record: SessionHistoryRecord): number {
+  if (record.type === 'event') return record.event.seq
+  const length = record.event.type === 'chunkrow/tool-call-chunks'
+    ? record.event.data.args.length
+    : record.event.data.texts.length
+  return record.event.seq + length - 1
 }
diff --git a/packages/api/session-controller/src/client/sessions/session.ts b/packages/api/session-controller/src/client/sessions/session.ts
index 7239e3149a..182d8514d9 100644
--- a/packages/api/session-controller/src/client/sessions/session.ts
+++ b/packages/api/session-controller/src/client/sessions/session.ts
@@ -7,7 +7,7 @@ import type {
   IApiClient, SubagentAddress,
 } from '@deepseek-ai/dsh-client-connection/client'
 import type { MessageId } from '@deepseek-ai/dsh-llm/brand'
-import type { SessionEvent, SessionId } from '@deepseek-ai/dsh-session/types'
+import type { SessionId } from '@deepseek-ai/dsh-session/types'
 import {
   SessionEventStream,
   sessionStreamFailure,
@@ -18,7 +18,6 @@ import type {
   QueueAction,
   SessionAddress,
   SessionControlFrame,
-  SessionEventEntry,
   SessionQueuedItem,
   SessionRequestId,
   SessionError,
@@ -30,6 +29,9 @@ import type {
   OpenState, PromptError, SessionSnapshot,
 } from '../contract/snapshot.ts'
 import { MutableSessionEventSource } from '../contract/events.ts'
+import type {
+  SessionEventLikeEntry, SessionLiveEventEntry,
+} from '../contract/events.ts'
 import { Notifier } from './notifier.ts'
 import type { RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { SessionRemotes } from './remotes.ts'
@@ -72,7 +74,6 @@ export interface SessionOptions {
  */
 export class Session implements SessionFace {
   // ---- Window and derived state (all private; the snapshot is the only read API) ----
-  private eventWindow: SessionEvent[] = []
   private baseSeq = 0
   private hasMore = false
   private openState: OpenState = 'cold'
@@ -400,7 +401,6 @@ export class Session implements SessionFace {
     this.openPromise = null
     this.openState = 'cold'
     this.openError = null
-    this.eventWindow = []
     this.baseSeq = 0
     this.notifier.markDirty()
     await this.open()
@@ -575,28 +575,25 @@ export class Session implements SessionFace {
   }
 
   /** Replace the complete contiguous window and apply page-owned projection metadata. */
-  private installWindow(entries: readonly SessionEventEntry[], hasMore: boolean, projections?: ProjectionsBaseline): void {
-    this.eventWindow = entries.map(entry => entry.event as SessionEvent)
-    this.baseSeq = this.eventWindow[0]?.seq ?? 0
+  private installWindow(entries: readonly SessionEventLikeEntry[], hasMore: boolean, projections?: ProjectionsBaseline): void {
+    this.baseSeq = entries[0]?.event.seq ?? 0
     this.hasMore = hasMore
-    if (this.eventWindow.some(event => event.type === 'turn/start')) this.firstPromptPendingTurn = false
+    if (entries.some(entry => entry.event.type === 'turn/start')) this.firstPromptPendingTurn = false
     if (projections !== undefined) this.projections.seed(projections)
     this.eventSource.replace(entries, hasMore)
     this.notifier.markDirty()
   }
 
   /** Prepend one stream-validated history page. */
-  private prependWindow(entries: readonly SessionEventEntry[], hasMore: boolean): void {
-    this.eventWindow = [...entries.map(entry => entry.event as SessionEvent), ...this.eventWindow]
-    this.baseSeq = this.eventWindow[0]?.seq ?? 0
+  private prependWindow(entries: readonly SessionEventLikeEntry[], hasMore: boolean): void {
+    this.baseSeq = entries[0]?.event.seq ?? this.baseSeq
     this.hasMore = hasMore
     this.eventSource.prepend(entries, hasMore)
   }
 
   /** Append one stream-validated live event. */
-  private appendLive(entry: SessionEventEntry): boolean {
-    const event = entry.event as SessionEvent
-    this.eventWindow.push(event)
+  private appendLive(entry: SessionLiveEventEntry): boolean {
+    const event = entry.event
     const awaitingFirstTurn = this.firstPromptPendingTurn
     if (event.type === 'turn/start') this.firstPromptPendingTurn = false
     const queueChanged = this.queueMirror.acceptDurable(event)
diff --git a/packages/api/session-controller/src/client/transport.ts b/packages/api/session-controller/src/client/transport.ts
index c46926ed39..48298268bb 100644
--- a/packages/api/session-controller/src/client/transport.ts
+++ b/packages/api/session-controller/src/client/transport.ts
@@ -14,12 +14,17 @@ import {
 import type {
   SessionAddress,
   SessionControlFrame,
-  SessionEventEntry,
+  SessionHistoryRecord,
   SessionPage,
   SessionPageRequest,
   SessionProjectionBaseline,
 } from '../types.ts'
-import { historyEntries } from './sessions/history-records.ts'
+import {
+  historyEntries,
+  historyRecordFirstSeq,
+  historyRecordLastSeq,
+} from './sessions/history-records.ts'
+import type { SessionEventLikeEntry, SessionLiveEventEntry } from './contract/events.ts'
 
 export {
   SESSION_SEARCH_RESULT_LIMIT,
@@ -38,7 +43,33 @@ interface SessionJournalPage extends SessionPage {
 }
 
 /** One complete publication from the Session journal stream. */
-export type SessionJournalChange = RemoteJournalChange<SessionJournalPage, SessionEventEntry>
+export type SessionJournalChange =
+  | {
+    readonly type: 'replace' | 'prepend'
+    readonly page: SessionJournalPage
+    readonly entries: readonly SessionEventLikeEntry[]
+    readonly hasMore: boolean
+  }
+  | { readonly type: 'append'; readonly entry: SessionLiveEventEntry }
+
+function toSessionJournalChange(
+  change: RemoteJournalChange<SessionJournalPage, SessionHistoryRecord>,
+): SessionJournalChange {
+  switch (change.type) {
+    case 'replace':
+    case 'prepend':
+      return { ...change, entries: historyEntries(change.entries) }
+    case 'append': {
+      if (change.entry.type !== 'event') {
+        throw new Error('session live stream emitted a packed history record')
+      }
+      return {
+        type: 'append',
+        entry: change.entry as unknown as SessionLiveEventEntry,
+      }
+    }
+  }
+}
 
 type SessionControlBaselineFrame = Extract<SessionControlFrame, { type: 'baseline' }>
 type SessionControlDeltaFrame = Exclude<SessionControlFrame, SessionControlBaselineFrame>
@@ -101,7 +132,7 @@ export function createSessionControlStream(
 /** Gateway-owned event journal bound to one ordinary or direct-subagent Session address. */
 export class SessionEventStream extends RemoteJournalStream<
   SessionJournalPage,
-  SessionEventEntry,
+  SessionHistoryRecord,
   number,
   ClientSessionPageRequest
 > {
@@ -118,12 +149,13 @@ export class SessionEventStream extends RemoteJournalStream<
     super(remote, {
       name: 'session event stream',
       emptyCursor: -1,
-      entries: page => historyEntries(page.records),
+      entries: page => page.records,
       hasMore: page => page.hasMore,
-      cursor: entry => entry.event.seq,
+      first: historyRecordFirstSeq,
+      last: historyRecordLastSeq,
       compare: (left, right) => left - right,
       follows: (left, right) => right === left + 1,
-      publish: options.publish,
+      publish: (change) => { options.publish(toSessionJournalChange(change)) },
       ...(options.carrierFailed === undefined
         ? {}
         : { carrierFailed: options.carrierFailed }),
@@ -135,7 +167,7 @@ export class SessionEventStream extends RemoteJournalStream<
   protected override async * follow(
     request: ClientSessionPageRequest,
     signal: AbortSignal,
-  ): AsyncIterable<RemoteJournalFrame<SessionEventEntry, number, SessionJournalPage>> {
+  ): AsyncIterable<RemoteJournalFrame<SessionHistoryRecord, number, SessionJournalPage>> {
     for await (const frame of this.remote.session.follow({
       address: this.address,
       ...(request.maxMessages === undefined ? {} : { maxMessages: request.maxMessages }),
@@ -152,8 +184,7 @@ export class SessionEventStream extends RemoteJournalStream<
         }
         continue
       }
-      const { type: _type, ...entry } = frame
-      yield { type: 'entry', entry }
+      yield { type: 'entry', entry: frame }
     }
   }
 
diff --git a/packages/api/session-controller/src/history.ts b/packages/api/session-controller/src/history.ts
index 99f521ddf6..d78509e49b 100644
--- a/packages/api/session-controller/src/history.ts
+++ b/packages/api/session-controller/src/history.ts
@@ -2,13 +2,14 @@
 
 import type { Context } from '@deepseek-ai/cordis'
 import { isAppendSurfaceEvent } from '@deepseek-ai/dsh-session'
-import { isChunkRow, packChunkRuns } from '@deepseek-ai/dsh-session/chunk-rows'
+import { isChunkRow, packChunkRuns, type ChunkRow } from '@deepseek-ai/dsh-session/chunk-rows'
 import type { SessionEvent, SessionHeader, SessionId } from '@deepseek-ai/dsh-session'
 import { SessionQueryError, type SessionObservation } from '@deepseek-ai/dsh-session-query'
 import type {} from '@deepseek-ai/dsh-subagent'
 import { TypertRemoteFailure } from '@deepseek-ai/dsh-typert-protocol'
 import type {
   SessionAddress,
+  SessionChunkRun,
   SessionEventEntry,
   SessionFollowRequest,
   SessionFollowFrame,
@@ -157,7 +158,7 @@ export class SessionHistoryController {
           reject('internal', `session event stream skipped seq ${String(nextSeq)}`, {})
         }
         nextSeq++
-        yield { type: 'event', ...entryFor(item) }
+        yield entryFor(item)
       }
     } finally {
       this.closeFollowers.delete(close)
@@ -315,14 +316,35 @@ function paginate(
 
 function entryFor(event: SessionEvent): SessionEventEntry {
   return {
+    type: 'event',
     // Session.append validates and freezes event data as JSON before publication.
     event: event as unknown as SessionWireEvent,
   }
 }
 
+function chunkEntryFor(row: ChunkRow): SessionChunkRun {
+  switch (row.type) {
+    case 'text-chunks':
+      return {
+        type: 'chunks',
+        event: { type: 'chunkrow/text-chunks', seq: row.seq0, time: row.time0, data: row.data },
+      }
+    case 'reasoning-chunks':
+      return {
+        type: 'chunks',
+        event: { type: 'chunkrow/reasoning-chunks', seq: row.seq0, time: row.time0, data: row.data },
+      }
+    case 'tool-call-chunks':
+      return {
+        type: 'chunks',
+        event: { type: 'chunkrow/tool-call-chunks', seq: row.seq0, time: row.time0, data: row.data },
+      }
+  }
+}
+
 /** Encode one bounded logical page without changing its pagination cut. */
 function pageRecords(events: readonly SessionEvent[]): SessionHistoryRecord[] {
   return packChunkRuns(events).map(record => isChunkRow(record)
-    ? { chunks: record }
+    ? chunkEntryFor(record)
     : entryFor(record))
 }
diff --git a/packages/api/session-controller/src/types.ts b/packages/api/session-controller/src/types.ts
index 94fc0865c5..5f02c41765 100644
--- a/packages/api/session-controller/src/types.ts
+++ b/packages/api/session-controller/src/types.ts
@@ -362,12 +362,24 @@ export type SessionAddress =
 
 /** One raw Session event in the Remote journal. */
 export interface SessionEventEntry {
+  readonly type: 'event'
   readonly event: SessionWireEvent
 }
 
+/** Event-shaped wire representation of one packed chunk row. */
+export type ChunkRowEvent = {
+  [Kind in ChunkRow['type']]: {
+    readonly type: `chunkrow/${Kind}`
+    readonly seq: number
+    readonly time: number
+    readonly data: Extract<ChunkRow, { readonly type: Kind }>['data']
+  }
+}[ChunkRow['type']]
+
 /** One lossless run of consecutive Assistant delta events in a history page. */
 export interface SessionChunkRun {
-  readonly chunks: ChunkRow
+  readonly type: 'chunks'
+  readonly event: ChunkRowEvent
 }
 
 /** One history-page record: a raw event or a packed Assistant delta run. */
@@ -415,7 +427,7 @@ export type SessionFollowFrame =
     readonly hasMore: boolean
     readonly projections: SessionProjectionBaseline
   }
-  | ({ readonly type: 'event' } & SessionEventEntry)
+  | SessionEventEntry
 
 /** One pending inbox occurrence in the authoritative queue snapshot. */
 export interface SessionQueuedItem {
diff --git a/packages/api/session-controller/tests/client-contract.client.spec.ts b/packages/api/session-controller/tests/client-contract.client.spec.ts
index 9b3a7fa015..789fe04d6d 100644
--- a/packages/api/session-controller/tests/client-contract.client.spec.ts
+++ b/packages/api/session-controller/tests/client-contract.client.spec.ts
@@ -1,16 +1,17 @@
-import type { SessionEventEntry } from '@deepseek-ai/dsh-api-session-controller/types'
 import { describe, expect, it, vi } from 'vitest'
-import { MutableSessionEventSource } from '../src/client/contract/events.ts'
+import {
+  MutableSessionEventSource, type SessionLiveEventEntry,
+} from '../src/client/contract/events.ts'
 import { transportResult } from '../src/client/contract/result.ts'
 
-function entry(seq: number): SessionEventEntry {
+function entry(seq: number): SessionLiveEventEntry {
   return {
+    type: 'event',
     event: {
-      type: 'fixture/event',
+      type: 'turn/start',
       seq,
       time: seq,
-      data: { seq },
-      ignorable: true,
+      data: { turn: seq },
     },
   }
 }
diff --git a/packages/api/session-controller/tests/event-script.client.ts b/packages/api/session-controller/tests/event-script.client.ts
index d6f13da57d..4722192353 100644
--- a/packages/api/session-controller/tests/event-script.client.ts
+++ b/packages/api/session-controller/tests/event-script.client.ts
@@ -149,7 +149,7 @@ export function plainTurn(startSeq: number, turn: number, ask: string, answer: s
 
 /** Wrap raw events in the journal envelope returned by history. */
 export function entries(events: readonly SessionEvent[]): SessionEventEntry[] {
-  return events.map(event => ({ event: event as unknown as SessionWireEvent }))
+  return events.map(event => ({ type: 'event', event: event as unknown as SessionWireEvent }))
 }
 
 /** Build one view-less history response value. */
diff --git a/packages/api/session-controller/tests/fake-api.client.ts b/packages/api/session-controller/tests/fake-api.client.ts
index c2d858150a..b8725dfee4 100644
--- a/packages/api/session-controller/tests/fake-api.client.ts
+++ b/packages/api/session-controller/tests/fake-api.client.ts
@@ -28,7 +28,7 @@ import {
 } from '@deepseek-ai/dsh-api-gateway/client'
 import { RpcId } from '@deepseek-ai/dsh-client-connection/client'
 import type { SessionRemotes } from '../src/client/sessions/remotes.ts'
-import { historyEntries } from '../src/client/sessions/history-records.ts'
+import { historyRecordLastSeq } from '../src/client/sessions/history-records.ts'
 
 const AVAILABLE_STREAM_CONNECTION = {
   hostDescription: {
@@ -440,8 +440,8 @@ export class FakeApiClient implements IApiClient {
       ok: true,
       value: {
         ...result.value,
-        records: historyEntries(result.value.records)
-          .filter(entry => entry.event.seq <= request.throughSeq),
+        records: result.value.records
+          .filter(record => historyRecordLastSeq(record) <= request.throughSeq),
       },
     }
   }
@@ -469,8 +469,8 @@ export class FakeApiClient implements IApiClient {
         )
       }
       const page = response.result.value
-      const entries = historyEntries(page.records)
-      const cursor = this.followCursor ?? entries.at(-1)?.event.seq ?? -1
+      const tail = page.records.at(-1)
+      const cursor = this.followCursor ?? (tail === undefined ? -1 : historyRecordLastSeq(tail))
       yield {
         type: 'snapshot',
         header: {
@@ -482,7 +482,7 @@ export class FakeApiClient implements IApiClient {
             : {}),
         },
         cursor,
-        records: entries.filter(entry => entry.event.seq <= cursor),
+        records: page.records.filter(record => historyRecordLastSeq(record) <= cursor),
         hasMore: page.hasMore,
         projections: page.projections ?? { asOfSeq: cursor, values: {} },
       }
diff --git a/packages/api/session-controller/tests/history-records.client.spec.ts b/packages/api/session-controller/tests/history-records.client.spec.ts
index b0966e901b..4a91fb04a8 100644
--- a/packages/api/session-controller/tests/history-records.client.spec.ts
+++ b/packages/api/session-controller/tests/history-records.client.spec.ts
@@ -1,50 +1,60 @@
-/** Packed history records decode to the exact Session event stream. */
+/** Packed history records become one event-shaped Client value per wire record. */
 
 import { describe, expect, it } from 'vitest'
 import { CallId } from '@deepseek-ai/dsh-llm/brand'
-import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import type { SessionHistoryRecord } from '../src/types.ts'
-import { historyEntries } from '../src/client/sessions/history-records.ts'
+import {
+  historyEntries,
+  historyRecordFirstSeq,
+  historyRecordLastSeq,
+} from '../src/client/sessions/history-records.ts'
 
-describe('historyEntries', () => {
-  it('keeps ordinary entries and expands every packed text member with its exact boundary', () => {
-    const ordinary = {
-      event: { type: 'turn/start', seq: 0, time: 1, data: { turn: 1 } },
-    } as SessionHistoryRecord
+describe('Session history record projection', () => {
+  it('retains an ordinary event and its point cursor', () => {
+    const ordinary: SessionHistoryRecord = {
+      type: 'event',
+      event: { type: 'turn/start', seq: 7, time: 1, data: { turn: 1 } },
+    }
+
+    const records = [ordinary]
+    const [entry] = historyEntries(records)
+
+    expect(historyEntries(records)).toBe(records)
+    expect(entry).toBe(ordinary)
+    expect(historyRecordFirstSeq(ordinary)).toBe(7)
+    expect(entry?.event.time).toBe(1)
+    expect(historyRecordLastSeq(ordinary)).toBe(7)
+  })
+
+  it('retains one packed text row without copying or reshaping it', () => {
     const packed: SessionHistoryRecord = {
-      chunks: {
-        type: 'text-chunks',
-        seq0: 1,
-        time0: 2,
-        data: { turn: 1, step: 1, index: 0, dt: [1, 1, 1], texts: ['a', 'b', 'c', 'd'] },
+      type: 'chunks',
+      event: {
+        type: 'chunkrow/text-chunks',
+        seq: 11,
+        time: 20,
+        data: { turn: 1, step: 2, index: 0, dt: [1, 2, 3], texts: ['a', 'b', 'c', 'd'] },
       },
     }
 
-    const entries = historyEntries([ordinary, packed])
+    const [entry] = historyEntries([packed])
+    if (entry?.type !== 'chunks') throw new Error('expected packed history entry')
+    const { event } = entry
 
-    expect(entries).toHaveLength(5)
-    expect(entries[0]).toBe(ordinary)
-    expect(entries.slice(1).map((entry) => {
-      const event = entry.event as unknown as SessionEvent<'assistant/chunk'>
-      return {
-        seq: event.seq,
-        time: event.time,
-        chunk: event.data.chunk,
-      }
-    })).toEqual([
-      { seq: 1, time: 2, chunk: { type: 'text-delta', index: 0, text: 'a' } },
-      { seq: 2, time: 3, chunk: { type: 'text-delta', index: 0, text: 'b' } },
-      { seq: 3, time: 4, chunk: { type: 'text-delta', index: 0, text: 'c' } },
-      { seq: 4, time: 5, chunk: { type: 'text-delta', index: 0, text: 'd' } },
-    ])
+    expect(entry).toBe(packed)
+    expect(event).toBe(packed.event)
+    expect(historyRecordFirstSeq(packed)).toBe(11)
+    expect(event.time).toBe(20)
+    expect(historyRecordLastSeq(packed)).toBe(14)
   })
 
-  it('preserves every tool-call fragment and optional-name presence', () => {
+  it('preserves a packed tool-call row and optional-name absence', () => {
     const packed: SessionHistoryRecord = {
-      chunks: {
-        type: 'tool-call-chunks',
-        seq0: 20,
-        time0: 200,
+      type: 'chunks',
+      event: {
+        type: 'chunkrow/tool-call-chunks',
+        seq: 20,
+        time: 200,
         data: {
           turn: 2,
           step: 4,
@@ -56,14 +66,13 @@ describe('historyEntries', () => {
       },
     }
 
-    const events = historyEntries([packed])
-      .map(entry => entry.event as unknown as SessionEvent<'assistant/chunk'>)
+    const [entry] = historyEntries([packed])
+    if (entry?.type !== 'chunks') throw new Error('expected packed history entry')
+    const { event } = entry
 
-    expect(events).toMatchObject([
-      { seq: 20, time: 200, data: { chunk: { argumentsDelta: '' } } },
-      { seq: 21, time: 202, data: { chunk: { argumentsDelta: '{"x":' } } },
-      { seq: 22, time: 205, data: { chunk: { argumentsDelta: '1}' } } },
-    ])
-    expect(events.every(event => !Object.hasOwn(event.data.chunk, 'name'))).toBe(true)
+    if (event.type !== 'chunkrow/tool-call-chunks') throw new Error('expected packed history event')
+    expect(event).toBe(packed.event)
+    expect(Object.hasOwn(event.data, 'name')).toBe(false)
+    expect(historyRecordLastSeq(packed)).toBe(22)
   })
 })
diff --git a/packages/api/session-controller/tests/session-cold.host.spec.ts b/packages/api/session-controller/tests/session-cold.host.spec.ts
index 6a50d34e6f..7156ac569d 100644
--- a/packages/api/session-controller/tests/session-cold.host.spec.ts
+++ b/packages/api/session-controller/tests/session-cold.host.spec.ts
@@ -390,7 +390,7 @@ describe('cold history recovery view', () => {
       maxMessages: 10,
     })
     if (!history.ok) throw new Error('history failed')
-    expect(history.value.records.map(record => 'event' in record ? record.event : record.chunks)).toMatchInlineSnapshot(`
+    expect(history.value.records.map(record => record.event)).toMatchInlineSnapshot(`
       [
         {
           "data": {
@@ -564,7 +564,7 @@ describe('subagent ownership fence', () => {
       },
       throughSeq: 3,
     }, new AbortController().signal)
-    expect(history.records.map(record => 'event' in record ? record.event.type : record.chunks.type))
+    expect(history.records.map(record => record.event.type))
       .toEqual(events.map(event => event.type))
     expect(ctx.agents.get(sessionId)).toBeUndefined()
 
diff --git a/packages/api/session-controller/tests/session-history-journal.host.spec.ts b/packages/api/session-controller/tests/session-history-journal.host.spec.ts
index 4f856a0995..e1741cf4fd 100644
--- a/packages/api/session-controller/tests/session-history-journal.host.spec.ts
+++ b/packages/api/session-controller/tests/session-history-journal.host.spec.ts
@@ -4,11 +4,12 @@ import { describe, expect, it, vi } from 'vitest'
 import { Context } from '@deepseek-ai/cordis'
 import AgentRegistry from '@deepseek-ai/dsh-agent'
 import SessionStore from '@deepseek-ai/dsh-session'
-import { decodeStorageRecord } from '@deepseek-ai/dsh-session/chunk-rows'
+import { decodeStorageRecord, type ChunkRow } from '@deepseek-ai/dsh-session/chunk-rows'
 import { CallId, createMessage, createToolResultMessage, createUserMessage } from '@deepseek-ai/dsh-llm'
 import type { Session, SessionEvent, SessionId } from '@deepseek-ai/dsh-session'
 import { SessionHistoryController } from '@deepseek-ai/dsh-api-session-controller/src/history.ts'
 import type {
+  ChunkRowEvent,
   SessionFollowFrame,
   SessionPage,
   SessionWireEvent,
@@ -84,9 +85,20 @@ async function openFollow(
 
 /** Expand packed page records for assertions over the logical journal. */
 function pageEvents(page: SessionPage): SessionWireEvent[] {
-  return page.records.flatMap(record => 'event' in record
+  return page.records.flatMap(record => record.type === 'event'
     ? [record.event]
-    : decodeStorageRecord(record.chunks).map(event => event as unknown as SessionWireEvent))
+    : decodeStorageRecord(chunkRow(record.event)).map(event => event as unknown as SessionWireEvent))
+}
+
+function chunkRow(event: ChunkRowEvent): ChunkRow {
+  switch (event.type) {
+    case 'chunkrow/text-chunks':
+      return { type: 'text-chunks', seq0: event.seq, time0: event.time, data: event.data }
+    case 'chunkrow/reasoning-chunks':
+      return { type: 'reasoning-chunks', seq0: event.seq, time0: event.time, data: event.data }
+    case 'chunkrow/tool-call-chunks':
+      return { type: 'tool-call-chunks', seq0: event.seq, time0: event.time, data: event.data }
+  }
 }
 
 describe('Session history raw journal', () => {
@@ -182,9 +194,9 @@ describe('Session history raw journal', () => {
     expect(response.ok).toBe(true)
     if (!response.ok) throw new Error('unreachable')
     expect(response.value.records).toEqual([
-      { event: start },
-      { event: call },
-      { event: result },
+      { type: 'event', event: start },
+      { type: 'event', event: call },
+      { type: 'event', event: result },
     ])
   })
 
@@ -270,7 +282,7 @@ describe('Session history raw journal', () => {
       })
       if (!response.ok) throw new Error('unreachable')
       expect(pageEvents(response.value).map(event => event.seq)).toEqual([...sources, message.seq])
-      expect(response.value.records.filter(record => 'chunks' in record)).toHaveLength(1)
+      expect(response.value.records.filter(record => record.type === 'chunks')).toHaveLength(1)
       expect(response.value.hasMore).toBe(true)
     } finally {
       min.mockRestore()
@@ -286,11 +298,17 @@ describe('Session history raw journal', () => {
     const iterator = stream[Symbol.asyncIterator]()
 
     session.append('turn/start', { turn: 1 })
-    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'turn/start' } } })
+    await expect(iterator.next()).resolves.toMatchObject({
+      value: { type: 'event', event: { type: 'turn/start' } },
+    })
     session.append('tool/call', { turn: 1, step: 1, callId: CallId('c-late'), name: 'term', arguments: '{"cmd":"tail"}' })
-    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'tool/call' } } })
+    await expect(iterator.next()).resolves.toMatchObject({
+      value: { type: 'event', event: { type: 'tool/call' } },
+    })
     session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
-    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'turn/end' } } })
+    await expect(iterator.next()).resolves.toMatchObject({
+      value: { type: 'event', event: { type: 'turn/end' } },
+    })
     const events = vi.spyOn(session, 'events', 'get').mockImplementation(() => {
       throw new Error('live result rescanned Session history')
     })
diff --git a/packages/api/session-controller/tests/session-projections.host.spec.ts b/packages/api/session-controller/tests/session-projections.host.spec.ts
index 8468a5af0b..fd30f66158 100644
--- a/packages/api/session-controller/tests/session-projections.host.spec.ts
+++ b/packages/api/session-controller/tests/session-projections.host.spec.ts
@@ -153,7 +153,7 @@ describe('session.history projections block', () => {
     expect(projections.values['test/last-user']).toEqual({ text: 'm2' })
     // asOfSeq IS the window tail: the last served event carries it.
     const last = records.at(-1)
-    expect(last !== undefined && 'event' in last ? last.event.seq : last?.chunks.seq0).toBe(projections.asOfSeq)
+    expect(last?.event.seq).toBe(projections.asOfSeq)
   })
 
   it('returns a complete current replacement cut on each follow generation', async () => {
@@ -163,7 +163,7 @@ describe('session.history projections block', () => {
 
     const snapshot = await opening(remote(ctx), session.id)
 
-    expect(snapshot.records.map(record => 'event' in record ? record.event.seq : record.chunks.seq0)).toEqual([0, 1])
+    expect(snapshot.records.map(record => record.event.seq)).toEqual([0, 1])
     expect(snapshot.projections.asOfSeq).toBe(1)
     expect(snapshot.projections.values).toEqual(
       expect.objectContaining({ 'test/last-user': { text: 'm1' } }),
diff --git a/packages/api/session-controller/tests/session.client.spec.ts b/packages/api/session-controller/tests/session.client.spec.ts
index d2cba21c81..6ee5bd9ba4 100644
--- a/packages/api/session-controller/tests/session.client.spec.ts
+++ b/packages/api/session-controller/tests/session.client.spec.ts
@@ -618,23 +618,23 @@ describe('remaining branches', () => {
     api.onHistory = () => Promise.resolve(ok({
       records: [
         ...entries(plainTurn(0, 0, 'a', 'b')),
-        { event: historyCall },
-        { event: historyResult },
+        { type: 'event', event: historyCall },
+        { type: 'event', event: historyResult },
       ] as never[],
       hasMore: false,
       modelSelection: { provider: 'deepseek-official', model: 'deepseek-v4-flash' },
     }))
     await session.open()
     expect(windowEntries(session).slice(-2)).toEqual([
-      { event: historyCall },
-      { event: historyResult },
+      { type: 'event', event: historyCall },
+      { type: 'event', event: historyResult },
     ])
     const liveCall = ev.toolCall(8, 2, 'l1', 'write', '{"file_path":"a.ts"}')
     await follow(api, liveCall)
-    expect(windowEntries(session).at(-1)).toEqual({ event: liveCall })
+    expect(windowEntries(session).at(-1)).toEqual({ type: 'event', event: liveCall })
     const liveResult = ev.toolResult(9, 2, 'l1', 'ok')
     await follow(api, liveResult)
-    expect(windowEntries(session).at(-1)).toEqual({ event: liveResult })
+    expect(windowEntries(session).at(-1)).toEqual({ type: 'event', event: liveResult })
   })
 })
 
diff --git a/packages/api/session-controller/tests/transport.client.spec.ts b/packages/api/session-controller/tests/transport.client.spec.ts
index 50b9d2c134..05d4ed21f9 100644
--- a/packages/api/session-controller/tests/transport.client.spec.ts
+++ b/packages/api/session-controller/tests/transport.client.spec.ts
@@ -19,6 +19,7 @@ import type {
   SessionEventEntry,
   SessionFollowFrame,
   SessionFollowRequest,
+  SessionHistoryRecord,
   SessionPage,
   SessionPageRequest,
 } from '../src/types.ts'
@@ -36,16 +37,28 @@ const AVAILABLE_CONNECTION = {
 }
 
 function entry(seq: number): SessionEventEntry {
-  return { event: { type: 'turn/start', seq, time: seq, data: { turn: seq } } }
+  return { type: 'event', event: { type: 'turn/start', seq, time: seq, data: { turn: seq } } }
 }
 
-function page(events: readonly SessionEventEntry[], hasMore = false): SessionPage {
-  return { records: events, hasMore }
+function chunks(seq0: number): SessionHistoryRecord {
+  return {
+    type: 'chunks',
+    event: {
+      type: 'chunkrow/text-chunks',
+      seq: seq0,
+      time: seq0,
+      data: { turn: 1, step: 1, index: 0, texts: ['a', 'b', 'c'], dt: [1, 1] },
+    },
+  }
+}
+
+function page(records: readonly SessionHistoryRecord[], hasMore = false): SessionPage {
+  return { records, hasMore }
 }
 
 function snapshot(
   cursor: number,
-  events: readonly SessionEventEntry[],
+  records: readonly SessionHistoryRecord[],
   hasMore = false,
 ): SessionFollowFrame {
   return {
@@ -56,7 +69,7 @@ function snapshot(
       createdAt: 0,
     },
     cursor,
-    records: events,
+    records,
     hasMore,
     projections: { asOfSeq: cursor, values: {} },
   }
@@ -123,13 +136,41 @@ class ScriptedSessionRemote implements SessionTransportRemote {
 }
 
 describe('Session Client stream adapters', () => {
+  it('validates a packed logical range before publishing one compact Client entry', async () => {
+    const row = chunks(1)
+    const remote = new ScriptedSessionRemote(
+      [{ frames: [snapshot(4, [entry(0), row, entry(4)]), entry(5)], hold: true }],
+      [],
+    )
+    const changes: SessionJournalChange[] = []
+    const stream = new SessionEventStream(sessionClient(remote), ADDRESS, {
+      publish: (change) => { changes.push(change) },
+      failed: vi.fn(),
+    })
+
+    await stream.open({})
+    await vi.waitFor(() => { expect(changes).toHaveLength(2) })
+
+    expect(changes[0]).toMatchObject({
+      type: 'replace',
+      entries: [
+        entry(0),
+        row,
+        entry(4),
+      ],
+    })
+    expect(changes[0]?.type === 'replace' ? changes[0].entries[1] : undefined).toBe(row)
+    expect(changes[1]).toEqual({ type: 'append', entry: entry(5) })
+    await stream.dispose()
+  })
+
   it('binds an event journal to one address and publishes replace, append, and prepend changes', async () => {
     const remote = new ScriptedSessionRemote(
       [{
         frames: [
           snapshot(3, [entry(2), entry(3)], true),
-          { type: 'event', ...entry(3) },
-          { type: 'event', ...entry(4) },
+          entry(3),
+          entry(4),
         ],
         hold: true,
       }],
@@ -165,7 +206,7 @@ describe('Session Client stream adapters', () => {
     const remote = new ScriptedSessionRemote(
       [
         {
-          frames: [snapshot(1, [entry(0), entry(1)]), { type: 'event', ...entry(2) }],
+          frames: [snapshot(1, [entry(0), entry(1)]), entry(2)],
           terminal: lost,
         },
         { frames: [snapshot(4, [entry(0), entry(1), entry(2), entry(3), entry(4)])], hold: true },
@@ -221,7 +262,7 @@ describe('Session Client stream adapters', () => {
 
   it('repairs a live gap without adding an absent message limit', async () => {
     const remote = new ScriptedSessionRemote(
-      [{ frames: [snapshot(0, [entry(0)]), { type: 'event', ...entry(2) }], hold: true }],
+      [{ frames: [snapshot(0, [entry(0)]), entry(2)], hold: true }],
       [{ ok: true, value: page([entry(0), entry(1), entry(2)]) }],
     )
     const changes: SessionJournalChange[] = []
diff --git a/packages/api/session-controller/tests/transport.host.spec.ts b/packages/api/session-controller/tests/transport.host.spec.ts
index 124a6d9c30..d23faacb94 100644
--- a/packages/api/session-controller/tests/transport.host.spec.ts
+++ b/packages/api/session-controller/tests/transport.host.spec.ts
@@ -87,7 +87,7 @@ describe('SessionHistoryController', () => {
       { address: { kind: 'session', sessionId: session.id }, throughSeq: 1 },
       new AbortController().signal,
     )
-    expect(page.records.map(entry => 'event' in entry ? entry.event.seq : entry.chunks.seq0)).toEqual([0, 1])
+    expect(page.records.map(entry => entry.event.seq)).toEqual([0, 1])
 
     abort.abort()
     expect(await iterator.next()).toMatchObject({ done: true })
@@ -137,7 +137,11 @@ describe('SessionHistoryController', () => {
       value: {
         type: 'snapshot',
         cursor: 2,
-        records: [{ event: { seq: 0 } }, { event: { seq: 1 } }, { event: { seq: 2 } }],
+        records: [
+          { type: 'event', event: { seq: 0 } },
+          { type: 'event', event: { seq: 1 } },
+          { type: 'event', event: { seq: 2 } },
+        ],
       },
     })
     session.append('turn/end', { turn: 2, reason: { kind: 'completed' } })
@@ -200,7 +204,12 @@ describe('SessionHistoryController', () => {
     await expect(opening).resolves.toMatchObject({
       done: false,
       value: {
-        type: 'snapshot', cursor: 1, records: [{ event: { seq: 0 } }, { event: { seq: 1 } }],
+        type: 'snapshot',
+        cursor: 1,
+        records: [
+          { type: 'event', event: { seq: 0 } },
+          { type: 'event', event: { seq: 1 } },
+        ],
       },
     })
     expect(attached.id).toBe(sessionId)
@@ -377,7 +386,9 @@ describe('SessionHistoryController', () => {
     await expect(transport.page({
       address: { kind: 'subagent', parentSessionId, childSessionId, mode: 'continuable' },
       throughSeq: 0,
-    }, signal)).resolves.toMatchObject({ records: [{ event: { type: 'subagent/descriptor' } }] })
+    }, signal)).resolves.toMatchObject({
+      records: [{ type: 'event', event: { type: 'subagent/descriptor' } }],
+    })
     await expect(transport.page({
       address: {
         kind: 'subagent',
@@ -505,7 +516,9 @@ describe('SessionHistoryController', () => {
     await expect(ordinaryBench.transport.page({
       address: { kind: 'session', sessionId: ordinaryId },
       throughSeq: 0,
-    }, signal())).resolves.toMatchObject({ records: [{ event: { seq: 0 } }] })
+    }, signal())).resolves.toMatchObject({
+      records: [{ type: 'event', event: { seq: 0 } }],
+    })
 
     const parentSessionId = SessionId('cold-parent')
     const childSessionId = SessionId('cold-child')
@@ -618,13 +631,13 @@ describe('SessionHistoryController', () => {
     const page = await transport.page({
       address: { kind: 'session', sessionId: session.id }, throughSeq: replacement.seq, maxMessages: 2,
     }, signal())
-    expect(page.records.map(entry => 'event' in entry ? entry.event.seq : entry.chunks.seq0))
+    expect(page.records.map(entry => entry.event.seq))
       .toEqual([3, 4, 5, replacement.seq])
     expect(page.hasMore).toBe(true)
     const before = await transport.page({
       address: { kind: 'session', sessionId: session.id }, throughSeq: replacement.seq, beforeSeq: 3, maxMessages: 1,
     }, signal())
-    expect(before.records.map(entry => 'event' in entry ? entry.event.seq : entry.chunks.seq0)).toEqual([2])
+    expect(before.records.map(entry => entry.event.seq)).toEqual([2])
   })
 
   it('keeps cited source events in the page that owns their appended message', async () => {
@@ -638,7 +651,7 @@ describe('SessionHistoryController', () => {
     const page = await transport.page({
       address: { kind: 'session', sessionId: session.id }, throughSeq: 1, maxMessages: 1,
     }, signal())
-    expect(page.records.map(entry => 'event' in entry ? entry.event.seq : entry.chunks.seq0)).toEqual([0, 1])
+    expect(page.records.map(entry => entry.event.seq)).toEqual([0, 1])
     expect(page.hasMore).toBe(false)
   })
 
diff --git a/packages/client/connection/src/client/fixture.ts b/packages/client/connection/src/client/fixture.ts
index 376f870f62..26fe838edc 100644
--- a/packages/client/connection/src/client/fixture.ts
+++ b/packages/client/connection/src/client/fixture.ts
@@ -75,11 +75,22 @@ interface FixtureProjectionsBlock {
 }
 
 interface FixtureHistoryEntry {
+  readonly type: 'event'
   readonly event: SessionEvent
 }
 
+type FixtureChunkRowEvent = {
+  [Kind in ChunkRow['type']]: {
+    readonly type: `chunkrow/${Kind}`
+    readonly seq: number
+    readonly time: number
+    readonly data: Extract<ChunkRow, { readonly type: Kind }>['data']
+  }
+}[ChunkRow['type']]
+
 interface FixtureHistoryChunkRun {
-  readonly chunks: ChunkRow
+  readonly type: 'chunks'
+  readonly event: FixtureChunkRowEvent
 }
 
 type FixtureHistoryRecord = FixtureHistoryEntry | FixtureHistoryChunkRun
@@ -114,7 +125,7 @@ type FixtureFollowFrame =
     readonly hasMore: boolean
     readonly projections: FixtureProjectionsBlock
   }
-  | ({ readonly type: 'event' } & FixtureHistoryEntry)
+  | FixtureHistoryEntry
 
 type FixtureFollowEventFrame = Extract<FixtureFollowFrame, { type: 'event' }>
 
@@ -1414,9 +1425,26 @@ function pageOf(
       break
     }
   }
-  const records = packChunkRuns(log.slice(start, end)).map((record): FixtureHistoryRecord => (
-    isChunkRow(record) ? { chunks: record } : { event: record }
-  ))
+  const records = packChunkRuns(log.slice(start, end)).map((record): FixtureHistoryRecord => {
+    if (!isChunkRow(record)) return { type: 'event', event: record }
+    switch (record.type) {
+      case 'text-chunks':
+        return {
+          type: 'chunks',
+          event: { type: 'chunkrow/text-chunks', seq: record.seq0, time: record.time0, data: record.data },
+        }
+      case 'reasoning-chunks':
+        return {
+          type: 'chunks',
+          event: { type: 'chunkrow/reasoning-chunks', seq: record.seq0, time: record.time0, data: record.data },
+        }
+      case 'tool-call-chunks':
+        return {
+          type: 'chunks',
+          event: { type: 'chunkrow/tool-call-chunks', seq: record.seq0, time: record.time0, data: record.data },
+        }
+    }
+  })
   return { records, hasMore: start > 0 }
 }
 
@@ -1884,7 +1912,7 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
     for (const conn of remoteEventConns.values()) conn.push(frame)
   }
   const emitFollow = (sessionId: SessionId, entry: FixtureHistoryEntry): void => {
-    for (const conn of followConns.get(sessionId) ?? []) conn.push({ type: 'event', ...entry })
+    for (const conn of followConns.get(sessionId) ?? []) conn.push(entry)
   }
 
   /** OK response echoing the caller's rpcId (contract: responses always backfill, never mint). */
@@ -1942,7 +1970,7 @@ function createFixtureWorld(options: FixtureOptions): FixtureWorld {
     const log = logOf(id)
     const event = { seq: log.length, time: Date.now(), ...e } as unknown as SessionEvent
     log.push(event)
-    emitFollow(id, { event })
+    emitFollow(id, { type: 'event', event })
     // Host eager-drive parallel: a unit-advancing event pushes its finished value.
     for (const frame of projectionFramesOf(id, log, event)) emitControl(frame)
     if (event.type === 'user/message' && event.data.source.kind === 'user') {
diff --git a/packages/client/connection/tests/fixture.client.spec.ts b/packages/client/connection/tests/fixture.client.spec.ts
index 06a7cd5448..77f996044b 100644
--- a/packages/client/connection/tests/fixture.client.spec.ts
+++ b/packages/client/connection/tests/fixture.client.spec.ts
@@ -37,11 +37,22 @@ interface FixtureSessionSummary {
 }
 
 interface FixtureHistoryEntry {
+  readonly type: 'event'
   readonly event: SessionEvent
 }
 
+type FixtureChunkRowEvent = {
+  [Kind in ChunkRow['type']]: {
+    readonly type: `chunkrow/${Kind}`
+    readonly seq: number
+    readonly time: number
+    readonly data: Extract<ChunkRow, { readonly type: Kind }>['data']
+  }
+}[ChunkRow['type']]
+
 interface FixtureHistoryChunkRun {
-  readonly chunks: ChunkRow
+  readonly type: 'chunks'
+  readonly event: FixtureChunkRowEvent
 }
 
 type FixtureHistoryRecord = FixtureHistoryEntry | FixtureHistoryChunkRun
@@ -52,9 +63,20 @@ interface FixturePage {
 }
 
 function historyEvents(records: readonly FixtureHistoryRecord[]): SessionEvent[] {
-  return records.flatMap(record => 'event' in record
+  return records.flatMap(record => record.type === 'event'
     ? [record.event]
-    : decodeStorageRecord(record.chunks))
+    : decodeStorageRecord(chunkRow(record.event)))
+}
+
+function chunkRow(event: FixtureChunkRowEvent): ChunkRow {
+  switch (event.type) {
+    case 'chunkrow/text-chunks':
+      return { type: 'text-chunks', seq0: event.seq, time0: event.time, data: event.data }
+    case 'chunkrow/reasoning-chunks':
+      return { type: 'reasoning-chunks', seq0: event.seq, time0: event.time, data: event.data }
+    case 'chunkrow/tool-call-chunks':
+      return { type: 'tool-call-chunks', seq0: event.seq, time0: event.time, data: event.data }
+  }
 }
 
 type FixtureFollowFrame =
@@ -68,7 +90,7 @@ type FixtureFollowFrame =
       readonly values: Readonly<Record<string, unknown>>
     }
   }
-  | ({ readonly type: 'event' } & FixtureHistoryEntry)
+  | FixtureHistoryEntry
 
 type FixtureControlFrame =
   | {
diff --git a/packages/extensions/tool-cordis/src/api-catalog.ts b/packages/extensions/tool-cordis/src/api-catalog.ts
index 64c6bed653..0d615e8c25 100644
--- a/packages/extensions/tool-cordis/src/api-catalog.ts
+++ b/packages/extensions/tool-cordis/src/api-catalog.ts
@@ -3343,6 +3343,10 @@ export const TYPE_API: readonly TypeApiEntry[] = [
     name: 'Branded',
     declaration: 'export type Branded<B extends string> = string & {\n    readonly [BRAND]: B;\n};',
   },
+  {
+    name: 'ChunkRowEvent',
+    declaration: 'export type ChunkRowEvent = {\n    [Kind in ChunkRow[\'type\']]: {\n        readonly type: `chunkrow/${Kind}`;\n        readonly seq: number;\n        readonly time: number;\n        readonly data: Extract<ChunkRow, {\n            readonly type: Kind;\n        }>[\'data\'];\n    };\n}[ChunkRow[\'type\']];',
+  },
   {
     name: 'ClientArtifactBaseline',
     declaration: 'export interface ClientArtifactBaseline {\n    readonly path: string;\n    readonly mtimeMs: number;\n    readonly size: number;\n    readonly mapMtimeMs: number | null;\n    readonly mapSize: number | null;\n}',
@@ -4445,7 +4449,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'SessionChunkRun',
-    declaration: 'export interface SessionChunkRun {\n    readonly chunks: ChunkRow;\n}',
+    declaration: 'export interface SessionChunkRun {\n    readonly type: \'chunks\';\n    readonly event: ChunkRowEvent;\n}',
   },
   {
     name: 'SessionControlBaseline',
@@ -4477,7 +4481,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'SessionEventEntry',
-    declaration: 'export interface SessionEventEntry {\n    readonly event: SessionWireEvent;\n}',
+    declaration: 'export interface SessionEventEntry {\n    readonly type: \'event\';\n    readonly event: SessionWireEvent;\n}',
   },
   {
     name: 'SessionEventMap',
@@ -4541,7 +4545,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'SessionFollowFrame',
-    declaration: 'export type SessionFollowFrame = {\n    readonly type: \'snapshot\';\n    readonly header: SessionHeader;\n    readonly cursor: number;\n    readonly records: readonly SessionHistoryRecord[];\n    readonly hasMore: boolean;\n    readonly projections: SessionProjectionBaseline;\n} | ({\n    readonly type: \'event\';\n} & SessionEventEntry);',
+    declaration: 'export type SessionFollowFrame = {\n    readonly type: \'snapshot\';\n    readonly header: SessionHeader;\n    readonly cursor: number;\n    readonly records: readonly SessionHistoryRecord[];\n    readonly hasMore: boolean;\n    readonly projections: SessionProjectionBaseline;\n} | SessionEventEntry;',
   },
   {
     name: 'SessionFollowRequest',