diff --git a/packages/api/session-controller/README.i18n.yaml b/packages/api/session-controller/README.i18n.yaml
index ef274f24bf..8ceb4a8da4 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: de20b2bacf0b563404b66f716c3ffdca01cb8058
-README.zh.md: cc94e573b0bc5d52323d06d010c12457749b1914
+README.md: 228ed88ed20b9f9581496468e47079afd1542e4f
+README.zh.md: edebf8bdda249cf0ea6797db7dd77fcfa973074a
diff --git a/packages/api/session-controller/README.md b/packages/api/session-controller/README.md
index de20b2bacf..228ed88ed2 100644
--- a/packages/api/session-controller/README.md
+++ b/packages/api/session-controller/README.md
@@ -54,8 +54,6 @@ A resume blocked by an existing write handle returns `session/writer-held` with
 
 Queue edits replace pending content with non-empty text only.
 
-Attachment authorization inspects only declared content fields of recognized Session events and completed assistant stream blocks. Unknown event payloads, unrelated fields, and extension data cannot authorize attachment reads.
-
 <a id="client-references"></a>
 ## Client references
 
diff --git a/packages/api/session-controller/README.zh.md b/packages/api/session-controller/README.zh.md
index cc94e573b0..edebf8bdda 100644
--- a/packages/api/session-controller/README.zh.md
+++ b/packages/api/session-controller/README.zh.md
@@ -54,8 +54,6 @@ Fork 复制 `atSeq` 所选的精确事件前缀，包含切点事件，允许在
 
 队列编辑仅允许用非空文本替换待处理内容。
 
-附件授权只检查已知 Session 事件声明的内容字段及已完成的 assistant 流块。未知事件载荷、无关字段和扩展数据不能授权读取附件。
-
 <a id="client-references"></a>
 ## Client 引用
 
diff --git a/packages/api/session-controller/package.json b/packages/api/session-controller/package.json
index e45f6b120d..643c553e0a 100644
--- a/packages/api/session-controller/package.json
+++ b/packages/api/session-controller/package.json
@@ -141,7 +141,6 @@
     "@deepseek-ai/dsh-remote-mock": "workspace:^",
     "@deepseek-ai/dsh-scope": "workspace:^",
     "@deepseek-ai/dsh-session": "workspace:^",
-    "@deepseek-ai/dsh-session-format-catalog": "workspace:^",
     "@deepseek-ai/dsh-session-persistence": "workspace:^",
     "@deepseek-ai/dsh-session-projection": "workspace:^",
     "@deepseek-ai/dsh-session-projection-cache": "workspace:^",
diff --git a/packages/api/session-controller/src/commands.ts b/packages/api/session-controller/src/commands.ts
index 4323315694..fa456772de 100644
--- a/packages/api/session-controller/src/commands.ts
+++ b/packages/api/session-controller/src/commands.ts
@@ -620,16 +620,19 @@ function imageBlockIn(
   if (!Array.isArray(content)) return undefined
   for (const value of content) {
     if (typeof value !== 'object' || value === null || Array.isArray(value)) continue
-    const block = value as { readonly type?: unknown; readonly attachment?: unknown }
+    const block = value as { readonly type?: unknown; readonly attachment?: unknown; readonly content?: unknown }
     if (block.type === 'image' && typeof block.attachment === 'object' && block.attachment !== null) {
       const ref = block.attachment as ImageAttachmentRef
       if (match(ref)) return ref
     }
+    if (block.type === 'tool-result') {
+      const nested = imageBlockIn(block.content, match)
+      if (nested !== undefined) return nested
+    }
   }
   return undefined
 }
 
-/** Read only first-party declared content fields; unknown event payloads stay opaque. */
 function imageInEvent(
   event: SessionEvent,
   match: (ref: ImageAttachmentRef) => boolean,
@@ -637,46 +640,22 @@ function imageInEvent(
   const data = event.data as {
     readonly content?: unknown
     readonly message?: { readonly content?: unknown }
-    readonly inserted: readonly { readonly content?: unknown }[]
-    readonly messages: readonly { readonly content?: unknown }[]
-    readonly summary?: unknown
-    readonly rawOutput?: unknown
+    readonly inserted?: readonly { readonly content?: unknown }[]
   }
-  // First-party event payloads can be present without their producer plugin mounted.
-  const type: string = event.type
-  switch (type) {
-    case 'user/message':
-    case 'tool/ptc-dispatch':
-      return imageBlockIn(data.content, match)
-    case 'system/message':
-    case 'developer/message':
-    case 'tool/result':
-    case 'team/message/queued':
-      return imageBlockIn(data.message?.content, match)
-    case 'agent/inbox/spliced':
-    case 'session/title-llm-request': {
-      const messages = type === 'agent/inbox/spliced' ? data.inserted : data.messages
-      for (const message of messages) {
-        const found = imageBlockIn(message.content, match)
-        if (found !== undefined) return found
-      }
-      return undefined
-    }
-    case 'compaction/summary':
-      return imageBlockIn(data.summary, match) ?? imageBlockIn(data.rawOutput, match)
-    case 'assistant/message': {
-      const found = imageBlockIn(data.message?.content, match)
-      if (found !== undefined) return found
-      break
-    }
-    case 'assistant/attempt': break
-    default: return undefined
-  }
-  const assistant = event as SessionEvent<'assistant/message' | 'assistant/attempt'>
-  for (const chunk of assistantStreamChunks(assistant.data.stream, 'block-end')) {
-    const found = imageBlockIn([chunk.block], match)
+  const direct = imageBlockIn(data.content, match)
+  if (direct !== undefined) return direct
+  const message = imageBlockIn(data.message?.content, match)
+  if (message !== undefined) return message
+  for (const inserted of data.inserted ?? []) {
+    const found = imageBlockIn(inserted.content, match)
     if (found !== undefined) return found
   }
+  if (event.type === 'assistant/message' || event.type === 'assistant/attempt') {
+    for (const chunk of assistantStreamChunks(event.data.stream, 'block-end')) {
+      const found = imageBlockIn([chunk.block], match)
+      if (found !== undefined) return found
+    }
+  }
   return undefined
 }
 
diff --git a/packages/api/session-controller/tests/commands-queue-attachment.host.spec.ts b/packages/api/session-controller/tests/commands-queue-attachment.host.spec.ts
index 2dd7454c37..3f1a45967d 100644
--- a/packages/api/session-controller/tests/commands-queue-attachment.host.spec.ts
+++ b/packages/api/session-controller/tests/commands-queue-attachment.host.spec.ts
@@ -10,7 +10,6 @@ import SessionStore, {
   SESSION_FORMAT_VERSION, Session, SessionId, SessionLogOffset, SessionSeq,
 } from '@deepseek-ai/dsh-session'
 import type { SessionEvent, SessionHeader, UserMessage } from '@deepseek-ai/dsh-session'
-import { createSessionFormatCatalogWithChildren, historicalSessionFormatCatalog } from '@deepseek-ai/dsh-session-format-catalog'
 import { snapshotSubagentDescriptor, SUBAGENT_DESCRIPTOR_VERSION } from '@deepseek-ai/dsh-subagent'
 import { subagentIdentityProjectionDefinition } from '@deepseek-ai/dsh-subagent/src/projection.ts'
 import { describe, expect, it, vi } from 'vitest'
@@ -317,8 +316,7 @@ function imageRef(id: string): ImageAttachmentRef {
 }
 
 function event(type: string, seq: SessionSeq, data: unknown): SessionEvent {
-  const surface = ['user/message', 'system/message', 'developer/message', 'tool/result'].includes(type)
-  return { type, seq, time: seq + 1, data, ...surface ? { surfaceOp: 'append' } : {} } as SessionEvent
+  return { type, seq, time: seq + 1, data } as SessionEvent
 }
 
 async function persistedController(
@@ -350,90 +348,16 @@ async function persistedController(
 }
 
 describe('Session attachment authorization', () => {
-  it.each([
-    ['system/message', 'message'], ['developer/message', 'message'], ['tool/result', 'message'],
-    ['team/message/queued', 'message'], ['tool/ptc-dispatch', 'content'],
-    ['session/title-llm-request', 'messages'], ['compaction/summary', 'summary'], ['compaction/summary', 'rawOutput'],
-  ] as const)('reads the declared %s %s content without rewriting it', async (type, field) => {
-    const ref = imageRef(`${type}-${field}`)
-    const content = [{ type: 'image', attachment: ref }]
-    const source = type === 'system/message' ? { kind: 'system-prompt' }
-      : type === 'tool/result' ? { kind: 'tool', callId: 'declared-call' } : { kind: 'test' }
-    const data = field === 'message' ? { message: {
-      id: 'declared-message', role: type.split('/')[0], content, source,
-      ...type === 'tool/result' ? { toolCallId: 'declared-call' } : {},
-    } }
-      : field === 'messages' ? { messages: [{ content: [] }, { content }] } : { [field]: content }
-    const events = [event(type, SessionSeq(0), data)]
-    const saved = JSON.stringify(events)
-    const readImage = vi.fn((image: ImageAttachmentRef) => Promise.resolve({ ref: image, data: Uint8Array.of(1) }))
-    const fixture = await persistedController(events, readImage)
-    try {
-      await expect(fixture.controller.attachment({ sessionId: fixture.sessionId, attachmentId: ref.attachmentId }))
-        .resolves.toEqual({ attachment: ref, data: 'AQ==' })
-      expect(readImage).toHaveBeenCalledExactlyOnceWith(ref)
-      expect(JSON.stringify(events)).toBe(saved)
-    } finally {
-      await fixture.ctx.fiber.dispose()
-    }
-  })
-
-  it('ignores unrelated fields of a known message event and its content blocks', async () => {
-    const ref = imageRef('not-a-content-occurrence')
-    const content = [{ type: 'image', attachment: ref }]
-    const stored = event('user/message', SessionSeq(0), {
-      id: 'metadata', role: 'user', source: { kind: 'user' },
-      content: [{ type: 'text', text: 'no image', content }, { type: 'plugin:vendor', data: { content }, content }],
-      message: { content }, inserted: [{ content }],
-    })
-    const readImage = vi.fn((image: ImageAttachmentRef) => Promise.resolve({ ref: image, data: Uint8Array.of(1) }))
-    const fixture = await persistedController([stored], readImage)
-    try {
-      await expect(fixture.controller.attachment({ sessionId: fixture.sessionId, attachmentId: ref.attachmentId }))
-        .rejects.toMatchObject({ code: 'session/attachment-invalid' })
-      expect(readImage).not.toHaveBeenCalled()
-    } finally {
-      await fixture.ctx.fiber.dispose()
-    }
-  })
-
-  it('denies attachment access from a migrated unknown ignorable event', async () => {
-    const ref = imageRef('opaque-event-image')
-    const content = [{ type: 'message', message: {
-      role: 'tool', toolCallId: 'opaque-call', content: [{ type: 'image', attachment: ref }],
-    } }]
-    const header = { type: 'session', version: 3, id: 'cold-attachment', createdAt: 1, isSeeded: false, delegationDepth: 0 }
-    const original = { type: 'external/image-record', seq: 0, time: 1, ignorable: true, data: {
-      content, message: { content }, inserted: [{ content }],
-      stream: [{ type: 'chunk', time: 1, chunk: { type: 'block-end', index: 0, block: content[0] } }],
-    } }
-    const historical = historicalSessionFormatCatalog.createRestore(header, { recovery: 'strict', validation: 'current' })
-    historical.decodeRow(original)
-    expect(historical.finish().header.version).toBe(3)
-    const reader = createSessionFormatCatalogWithChildren([]).createRestore(header, { recovery: 'strict', validation: 'current' })
-    reader.decodeRow(original)
-    const converted = reader.finish()
-    expect(converted.events[0]).toMatchObject({ type: 'plugin:external/image-record', data: original.data })
-    const readImage = vi.fn((image: ImageAttachmentRef) => Promise.resolve({ ref: image, data: Uint8Array.of(1) }))
-    const fixture = await persistedController(converted.events as SessionEvent[], readImage)
-    try {
-      await expect(fixture.controller.attachment({ sessionId: fixture.sessionId, attachmentId: ref.attachmentId }))
-        .rejects.toMatchObject({ code: 'session/attachment-invalid', details: { reason: 'ATTACHMENT_NOT_REFERENCED' } })
-      expect(readImage).not.toHaveBeenCalled()
-    } finally {
-      await fixture.ctx.fiber.dispose()
-    }
-  })
-
-  it('finds references in direct, message, inserted, and streamed content', async () => {
+  it('finds references in direct, message, inserted, nested, and streamed content', async () => {
     const nested = imageRef('nested')
     const message = imageRef('message')
     const inserted = imageRef('inserted')
     const streamed = imageRef('streamed')
     const events: SessionEvent[] = [
-      { ...event('user/message', SessionSeq(0), {
-        id: 'direct', role: 'user', source: { kind: 'user' },
-        content: [null, [], { type: 'text', text: 'none' }, { type: 'image', attachment: nested }],
+      { ...event('fixture/direct', SessionSeq(0), {
+        content: [null, [], { type: 'tool-result', content: [{ type: 'text', text: 'none' }] }, {
+          type: 'tool-result', content: [{ type: 'image', attachment: nested }],
+        }],
       }), ignorable: true as const },
       {
         type: 'assistant/message', seq: SessionSeq(1), time: 2, surfaceOp: 'append',
@@ -527,7 +451,7 @@ describe('Session attachment authorization', () => {
     ]) {
       const ref = imageRef(`failure-${thrown.name}`)
       const fixture = await persistedController(
-        [event('user/message', SessionSeq(0), { id: 'failure', role: 'user', source: { kind: 'user' }, content: [{ type: 'image', attachment: ref }] })],
+        [event('fixture/content', SessionSeq(0), { content: [{ type: 'image', attachment: ref }] })],
         () => Promise.reject(thrown),
       )
       await expectFailure(fixture.controller.attachment({
diff --git a/packages/session-query/session-log-export/README.i18n.yaml b/packages/session-query/session-log-export/README.i18n.yaml
index f475fe9c87..a2c80bc2d6 100644
--- a/packages/session-query/session-log-export/README.i18n.yaml
+++ b/packages/session-query/session-log-export/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/session-query/session-log-export/README.md
-README.md: 7fa004df954260de16a6a151e3110e6adfbc0f09
-README.zh.md: 147ee93b3929473d4e78024ff0b4ccbd040a1220
+README.md: 79b8d572a75f57aa13a0dfaa823a04ad1e818f87
+README.zh.md: d6229927130e7200cd21df0da64d0ce9ec80ab2f
diff --git a/packages/session-query/session-log-export/README.md b/packages/session-query/session-log-export/README.md
index 7fa004df95..79b8d572a7 100644
--- a/packages/session-query/session-log-export/README.md
+++ b/packages/session-query/session-log-export/README.md
@@ -59,8 +59,6 @@ The Web bundle mounts the package with Connection, `dsh-commands`, `dsh-client-u
 
 The dialog reports three phases: preparing, download started, or failed. Closing the dialog does not cancel an in-flight download, and the dialog does not reopen when that operation later settles. One session admits one active download at a time; repeated gestures share that operation. The export includes the live session's newest events: the host endpoint flushes a live root session before reading, so a slash-triggered ZIP includes the `command/run` and `command/done` pair that started the download; cold persisted sessions need no flush. Each logical log uses the current generation's canonical filename inside the archive (`session.jsonl` for v0, otherwise `session.vN.jsonl`), including beneath each sub-session directory. Images use `media/<attachmentId>.<ext>`, and generic files use `files/<digest-prefix>/<digest>/<name>`. Generic-file bytes are read and compressed as bounded chunks, so exporting a large upload does not buffer it in full.
 
-Attachment collection reads only declared content fields of recognized Session events and completed assistant stream blocks. Unknown event payloads, unrelated fields, and extension data remain opaque; the exported log retains them unchanged.
-
 ### Failures
 
 The dialog shows a preparation error when the preflight fails before ZIP streaming starts — for example an unreachable or misconfigured host endpoint. A descendant or attachment read failure after the browser accepts the GET is reported by the browser download manager, not by the dialog.
diff --git a/packages/session-query/session-log-export/README.zh.md b/packages/session-query/session-log-export/README.zh.md
index 147ee93b39..d622992713 100644
--- a/packages/session-query/session-log-export/README.zh.md
+++ b/packages/session-query/session-log-export/README.zh.md
@@ -59,8 +59,6 @@ Web bundle 将本包与 Connection、`dsh-commands`、`dsh-client-ui-commands` 
 
 弹窗报告三个阶段：准备中、开始下载或失败。关闭弹窗不会取消正在进行的下载，该操作随后结束时弹窗也不会重新打开。每个会话同时只允许一项下载，重复操作共用该任务。导出包含实时会话的最新事件：Host 端点在读取前会 flush 活动的根会话，因此斜杠命令触发的 ZIP 会包含启动下载的 `command/run` 与 `command/done` 事件对；非活动的持久化会话不需要 flush。每份逻辑日志在归档中使用当前 generation 的规范文件名（v0 为 `session.jsonl`，其他版本为 `session.vN.jsonl`），每个子会话目录下也遵循同一规则。图片使用 `media/<attachmentId>.<ext>`，通用文件使用 `files/<digest-prefix>/<digest>/<name>`。通用文件以有界分块读取并压缩，因此导出大型上传文件时不会把它完整缓冲进内存。
 
-附件收集只读取已知 Session 事件声明的内容字段及已完成的 assistant 流块。未知事件载荷、无关字段和扩展数据保持不透明，导出的日志原样保留它们。
-
 ### 失败
 
 当 ZIP 流式传输开始前的预检失败时——例如 Host 端点不可达或配置错误——弹窗显示准备阶段错误。浏览器接受 GET 后发生的子会话或附件读取失败由浏览器下载管理器报告，不通过弹窗报告。
diff --git a/packages/session-query/session-log-export/src/archive.ts b/packages/session-query/session-log-export/src/archive.ts
index 3dbf5211e1..8728ca9878 100644
--- a/packages/session-query/session-log-export/src/archive.ts
+++ b/packages/session-query/session-log-export/src/archive.ts
@@ -196,8 +196,9 @@ function fileEntryPath(ref: FileAttachmentRef): string {
 }
 
 /**
- * Collect attachment references from one flat content array; all other block fields remain opaque.
- * @param content - a declared event content array.
+ * Collect every attachment reference inside one content array, descending into
+ * nested tool results the way the live attachment route does.
+ * @param content - an event content array (or nested tool-result content).
  * @param images - image dedupe map keyed by attachment id.
  * @param files - file dedupe map keyed by attachment id and stored name.
  */
@@ -212,7 +213,7 @@ function collectAttachmentRefs(
   while (pending.length > 0) {
     const value = pending.pop()
     if (typeof value !== 'object' || value === null || Array.isArray(value)) continue
-    const block = value as { type?: unknown; attachment?: unknown }
+    const block = value as { type?: unknown; attachment?: unknown; content?: unknown }
     if (block.type === 'image' && typeof block.attachment === 'object' && block.attachment !== null) {
       const ref = block.attachment as ImageAttachmentRef
       images.set(String(ref.attachmentId), ref)
@@ -221,12 +222,16 @@ function collectAttachmentRefs(
       const ref = block.attachment as FileAttachmentRef
       files.set(`${String(ref.attachmentId)}\u0000${ref.name}`, ref)
     }
+    if (Array.isArray(block.content)) {
+      for (const item of block.content) pending.push(item)
+    }
   }
 }
 
 /**
- * Collect references only from declared first-party content fields and completed
- * Assistant blocks. Unknown events and unrelated payload fields remain opaque.
+ * Collect every attachment reference one session event carries, across the same
+ * carriers the live attachment route scans (direct content, message content,
+ * inserted messages, and completed blocks in embedded Assistant streams).
  * @param event - one parsed JSONL event object.
  * @param images - image dedupe map keyed by attachment id.
  * @param files - file dedupe map keyed by attachment id and stored name.
@@ -236,40 +241,18 @@ function collectEventAttachmentRefs(
   images: Map<string, ImageAttachmentRef>,
   files: Map<string, FileAttachmentRef>,
 ): void {
-  if (typeof event !== 'object' || event === null || Array.isArray(event)) return
-  const row = event as { type?: unknown; data?: unknown }
-  const data = row.data
+  const data = (event as { data?: unknown }).data
   if (typeof data !== 'object' || data === null) return
   const carrier = data as {
     content?: unknown
     message?: { content?: unknown }
     inserted?: Array<{ content?: unknown }>
-    messages?: Array<{ content?: unknown }>
-    summary?: unknown
-    rawOutput?: unknown
     stream?: Array<{ type?: unknown; chunk?: { type?: unknown; block?: unknown } }>
   }
-  switch (row.type) {
-    case 'user/message': case 'tool/ptc-dispatch':
-      collectAttachmentRefs(carrier.content, images, files)
-      return
-    case 'system/message': case 'developer/message': case 'tool/result': case 'team/message/queued':
-      collectAttachmentRefs(carrier.message?.content, images, files)
-      return
-    case 'agent/inbox/spliced': case 'session/title-llm-request': {
-      const messages = row.type === 'agent/inbox/spliced' ? carrier.inserted : carrier.messages
-      for (const message of messages ?? []) collectAttachmentRefs(message.content, images, files)
-      return
-    }
-    case 'compaction/summary':
-      collectAttachmentRefs(carrier.summary, images, files)
-      collectAttachmentRefs(carrier.rawOutput, images, files)
-      return
-    case 'assistant/message':
-      collectAttachmentRefs(carrier.message?.content, images, files)
-      break
-    case 'assistant/attempt': break
-    default: return
+  collectAttachmentRefs(carrier.content, images, files)
+  if (carrier.message !== undefined) collectAttachmentRefs(carrier.message.content, images, files)
+  if (carrier.inserted !== undefined) {
+    for (const message of carrier.inserted) collectAttachmentRefs(message.content, images, files)
   }
   if (carrier.stream !== undefined) {
     for (const record of carrier.stream) {
diff --git a/packages/session-query/session-log-export/tests/archive.host.spec.ts b/packages/session-query/session-log-export/tests/archive.host.spec.ts
index 011896e79b..973dbe9d91 100644
--- a/packages/session-query/session-log-export/tests/archive.host.spec.ts
+++ b/packages/session-query/session-log-export/tests/archive.host.spec.ts
@@ -503,15 +503,6 @@ describe('session.export download endpoint', () => {
     expect(strFromU8(files[exportLogName] as Uint8Array)).toBe('')
   })
 
-  it('preserves non-event JSON and absent content carriers without discovering attachment lookalikes', async () => {
-    const content = [{ type: 'image', attachment: { attachmentId: 'not-an-occurrence', mediaType: 'image/png' } }]
-    const text = [null, [], false, { type: 'agent/inbox/spliced', data: { content } },
-      { type: 'session/title-llm-request', data: { content } }].map(value => JSON.stringify(value)).join('\n')
-    const files = await directZipFiles(text)
-    expect(Object.keys(files)).toEqual([exportLogName])
-    expect(strFromU8(files[exportLogName] as Uint8Array)).toBe(text)
-  })
-
   it('waits for response pull capacity before reading the next archive entry', async () => {
     const filler = {
       type: 'user/message', seq: SessionSeq(2), time: 1000,
@@ -806,63 +797,10 @@ describe('session.export download endpoint', () => {
     await expect(response.arrayBuffer()).rejects.toThrow('file bytes missing')
   })
 
-  it.each([
-    ['system/message', 'message'], ['developer/message', 'message'], ['team/message/queued', 'message'],
-    ['tool/ptc-dispatch', 'content'], ['session/title-llm-request', 'messages'],
-    ['compaction/summary', 'summary'], ['compaction/summary', 'rawOutput'],
-  ] as const)('exports attachments from the declared %s %s content', async (type, field) => {
-    const content = [{ type: 'image', attachment: { attachmentId: 'declared-image', mediaType: 'image/png', bytes: 4, width: 2, height: 2 } }]
-    const data = field === 'message' ? { message: { content } }
-      : field === 'messages' ? { messages: [{ content: [] }, { content }] } : { [field]: content }
-    const stored = log('session-root', undefined, [{ type, seq: SessionSeq(1), time: 1000, data } as unknown as SessionEvent])
-    const api = await buildApi({ 'session-root': stored })
-    const response = await toFetchHandler(api).fetch(new Request('http://host/api/session.export?sessionId=session-root'))
-    const files = unzipSync(await responseBytes(response))
-    expect(Object.keys(files).sort()).toEqual(['media/declared-image.png', exportLogName].sort())
-    expect(new TextDecoder().decode(files[exportLogName])).toBe(logText(stored))
-  })
-
-  it('keeps unrelated event fields and content-block extension fields out of attachment collection', async () => {
-    const content = [{ type: 'image', attachment: { attachmentId: 'not-an-occurrence', mediaType: 'image/png', bytes: 4, width: 2, height: 2 } }]
-    const event = { type: 'user/message', seq: SessionSeq(1), time: 1000, data: {
-      content: [{ type: 'text', text: 'no image', content }, { type: 'plugin:vendor', data: { content }, content }],
-      message: { content }, inserted: [{ content }],
-      stream: [{ type: 'chunk', chunk: { type: 'block-end', block: content[0] } }],
-    } } as unknown as SessionEvent
-    const stored = log('session-root', undefined, [event])
-    const readImage = vi.fn((ref: ImageAttachmentRef) => Promise.resolve(storedImage(String(ref.attachmentId), ref.mediaType)))
-    const api = await buildApi({ 'session-root': stored }, [], { attachments: readImage })
-    const response = await toFetchHandler(api).fetch(new Request('http://host/api/session.export?sessionId=session-root'))
-    const files = unzipSync(await responseBytes(response))
-    expect(Object.keys(files)).toEqual([exportLogName])
-    expect(new TextDecoder().decode(files[exportLogName])).toBe(logText(stored))
-    expect(readImage).not.toHaveBeenCalled()
-  })
-
-  it('exports an unknown ignorable event without reading attachments from its opaque payload', async () => {
-    const image = { type: 'image', attachment: { attachmentId: 'opaque-image', mediaType: 'image/png', bytes: 4, width: 2, height: 2 } }
-    const file = { type: 'file', attachment: { attachmentId: `sha256:${'e'.repeat(64)}`, name: 'opaque.txt', bytes: 5 } }
-    const content = [{ type: 'message', message: { role: 'tool', toolCallId: 'opaque', content: [image, file] } }]
-    const opaque = { type: 'plugin:external/image-record', seq: SessionSeq(1), time: 1000, ignorable: true, data: {
-      content, message: { content }, inserted: [{ content }],
-      stream: [{ type: 'chunk', time: 1000, chunk: { type: 'block-end', index: 0, block: content[0] } }],
-    } } as unknown as SessionEvent
-    const stored = log('session-root', undefined, [opaque])
-    const readImage = vi.fn((ref: ImageAttachmentRef) => Promise.resolve(storedImage(String(ref.attachmentId), ref.mediaType)))
-    const readFileStream = vi.fn(async function* (_ref: FileAttachmentRef) { yield new Uint8Array([1]) })
-    const api = await buildApi({ 'session-root': stored }, [], { attachments: readImage, readFileStream })
-    const response = await toFetchHandler(api).fetch(new Request('http://host/api/session.export?sessionId=session-root'))
-    const files = unzipSync(await responseBytes(response))
-    expect(Object.keys(files)).toEqual([exportLogName])
-    expect(new TextDecoder().decode(files[exportLogName])).toBe(logText(stored))
-    expect(readImage).not.toHaveBeenCalled()
-    expect(readFileStream).not.toHaveBeenCalled()
-  })
-
-  it('collects media referenced from flat tool results', async () => {
+  it('collects media referenced from nested tool results', async () => {
     const nested = {
-      type: 'tool/result', seq: SessionSeq(2), time: 2000,
-      data: { message: { role: 'tool', toolCallId: 'outer', content: [{ type: 'image', attachment: { attachmentId: 'nested-1', mediaType: 'image/webp', bytes: 4, width: 2, height: 2 } }] } },
+      type: 'assistant/message', seq: SessionSeq(2), time: 2000,
+      data: { content: [{ type: 'tool-result', content: [{ type: 'image', attachment: { attachmentId: 'nested-1', mediaType: 'image/webp', bytes: 4, width: 2, height: 2 } }] }] },
     } as unknown as SessionEvent
     const api = await buildApi({ 'session-root': log('session-root', undefined, [nested]) })
     const response = await toFetchHandler(api).fetch(
@@ -880,7 +818,7 @@ describe('session.export download endpoint', () => {
       data: { message: { role: 'assistant', content: ['noise', block('wrapped-1', 'image/jpeg')] } },
     } as unknown as SessionEvent
     const inserted = {
-      type: 'agent/inbox/spliced', seq: SessionSeq(3), time: 3000,
+      type: 'context/inserted', seq: SessionSeq(3), time: 3000,
       data: { inserted: [{ content: [block('inserted-1', 'image/gif')] }] },
     } as unknown as SessionEvent
     const attempt = {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 19396a2bbb..fd03c89885 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1142,9 +1142,6 @@ importers:
       '@deepseek-ai/dsh-session':
         specifier: workspace:^
         version: link:../../core/session
-      '@deepseek-ai/dsh-session-format-catalog':
-        specifier: workspace:^
-        version: link:../../session/session-format-catalog
       '@deepseek-ai/dsh-session-persistence':
         specifier: workspace:^
         version: link:../../session/session-persistence