From 173307ef28d897ae8747e68c98b85ea9e1ee47dd Mon Sep 17 00:00:00 2001
From: ekko <152005280+EKKOLearnAI@users.noreply.github.com>
Date: Thu, 7 May 2026 13:49:57 +0800
Subject: [PATCH] feat: add session export with full and compressed modes
 (#507)

Add export functionality that allows users to download session data
as JSON or plain text, with optional LLM-based context compression
for long conversations. Includes UI controls in chat panel, session
list, and history view, plus i18n strings for all 8 locales.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
---
 packages/client/src/api/hermes/sessions.ts    |  20 ++-
 .../src/components/hermes/chat/ChatPanel.vue  |  45 +++++-
 .../hermes/chat/SessionListItem.vue           |  49 +++++-
 packages/client/src/i18n/locales/de.ts        |   6 +
 packages/client/src/i18n/locales/en.ts        |   6 +
 packages/client/src/i18n/locales/es.ts        |   6 +
 packages/client/src/i18n/locales/fr.ts        |   6 +
 packages/client/src/i18n/locales/ja.ts        |   6 +
 packages/client/src/i18n/locales/ko.ts        |   6 +
 packages/client/src/i18n/locales/pt.ts        |   6 +
 packages/client/src/i18n/locales/zh.ts        |   6 +
 .../client/src/views/hermes/HistoryView.vue   |  45 +++++-
 .../server/src/controllers/hermes/sessions.ts |  86 ++++++++++
 .../context-compressor/export-compressor.ts   | 149 ++++++++++++++++++
 .../src/lib/context-compressor/index.ts       |  18 ++-
 packages/server/src/routes/hermes/sessions.ts |   1 +
 tests/server/sessions-controller.test.ts      |  93 +++++++++++
 tests/server/sessions-routes.test.ts          |  14 ++
 18 files changed, 554 insertions(+), 14 deletions(-)
 create mode 100644 packages/server/src/lib/context-compressor/export-compressor.ts

diff --git a/packages/client/src/api/hermes/sessions.ts b/packages/client/src/api/hermes/sessions.ts
index ffb27d1..95ef7ce 100644
--- a/packages/client/src/api/hermes/sessions.ts
+++ b/packages/client/src/api/hermes/sessions.ts
@@ -1,4 +1,4 @@
-import { request } from '../client'
+import { request, getApiKey, getBaseUrlValue } from '../client'
 
 export interface SessionSummary {
   id: string
@@ -147,6 +147,24 @@ export async function setSessionWorkspace(id: string, workspace: string | null):
   }
 }
 
+export async function exportSession(id: string, mode: 'full' | 'compressed' = 'full', ext: 'json' | 'txt' = 'json'): Promise<void> {
+  const baseUrl = getBaseUrlValue()
+  const token = getApiKey()
+  const url = `${baseUrl}/api/hermes/sessions/${id}/export?mode=${mode}&ext=${ext}&token=${encodeURIComponent(token)}`
+  const res = await fetch(url)
+  if (!res.ok) throw new Error('Export failed')
+  const blob = await res.blob()
+  const contentDisposition = res.headers.get('Content-Disposition') || ''
+  let filename = `session_${id}.${ext}`
+  const match = contentDisposition.match(/filename\*?=(?:UTF-8'')?([^;\n]+)/i)
+  if (match) filename = decodeURIComponent(match[1].replace(/"/g, ''))
+  const a = document.createElement('a')
+  a.href = URL.createObjectURL(blob)
+  a.download = filename
+  a.click()
+  URL.revokeObjectURL(a.href)
+}
+
 export interface UsageStatsResponse {
   total_input_tokens: number
   total_output_tokens: number
diff --git a/packages/client/src/components/hermes/chat/ChatPanel.vue b/packages/client/src/components/hermes/chat/ChatPanel.vue
index afd71f4..783c3ef 100644
--- a/packages/client/src/components/hermes/chat/ChatPanel.vue
+++ b/packages/client/src/components/hermes/chat/ChatPanel.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { renameSession, setSessionWorkspace, batchDeleteSessions } from "@/api/hermes/sessions";
+import { renameSession, setSessionWorkspace, batchDeleteSessions, exportSession } from "@/api/hermes/sessions";
 import { useChatStore, type Session } from "@/stores/hermes/chat";
 import { useSessionBrowserPrefsStore } from "@/stores/hermes/session-browser-prefs";
 import {
@@ -303,6 +303,28 @@ const contextMenuOptions = computed(() => [
   },
   { label: t("chat.rename"), key: "rename" },
   { label: t("chat.setWorkspace"), key: "workspace" },
+  {
+    label: t("chat.export"),
+    key: "export",
+    children: [
+      {
+        label: t("chat.exportFull"),
+        key: "export-full",
+        children: [
+          { label: "JSON", key: "export-full-json" },
+          { label: "TXT", key: "export-full-txt" },
+        ],
+      },
+      {
+        label: t("chat.exportCompressed"),
+        key: "export-compressed",
+        children: [
+          { label: "JSON", key: "export-compressed-json" },
+          { label: "TXT", key: "export-compressed-txt" },
+        ],
+      },
+    ],
+  },
   { label: t("chat.copySessionId"), key: "copy-id" },
 ]);
 
@@ -318,7 +340,15 @@ const showContextMenu = ref(false);
 const contextMenuX = ref(0);
 const contextMenuY = ref(0);
 
-function handleContextMenuSelect(key: string) {
+function parseExportKey(key: string): { mode: 'full' | 'compressed'; ext: 'json' | 'txt' } | null {
+  if (key === 'export-full-json') return { mode: 'full', ext: 'json' }
+  if (key === 'export-full-txt') return { mode: 'full', ext: 'txt' }
+  if (key === 'export-compressed-json') return { mode: 'compressed', ext: 'json' }
+  if (key === 'export-compressed-txt') return { mode: 'compressed', ext: 'txt' }
+  return null
+}
+
+async function handleContextMenuSelect(key: string) {
   showContextMenu.value = false;
   if (!contextSessionId.value) return;
   if (key === "pin") {
@@ -327,6 +357,17 @@ function handleContextMenuSelect(key: string) {
   }
   if (key === "copy-id") {
     copySessionId(contextSessionId.value);
+  } else if (parseExportKey(key)) {
+    const { mode, ext } = parseExportKey(key)!;
+    const loadingMsg = mode === "compressed" ? message.loading(t("chat.exportCompressing"), { duration: 0 }) : null;
+    try {
+      await exportSession(contextSessionId.value, mode, ext);
+      loadingMsg?.destroy();
+      message.success(t("chat.exportSuccess"));
+    } catch {
+      loadingMsg?.destroy();
+      message.error(t("chat.exportFailed"));
+    }
   } else if (key === "workspace") {
     const session = chatStore.sessions.find(
       (s) => s.id === contextSessionId.value,
diff --git a/packages/client/src/components/hermes/chat/SessionListItem.vue b/packages/client/src/components/hermes/chat/SessionListItem.vue
index 1c7d971..853b39f 100644
--- a/packages/client/src/components/hermes/chat/SessionListItem.vue
+++ b/packages/client/src/components/hermes/chat/SessionListItem.vue
@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { ref, onUnmounted } from 'vue'
 import { NPopconfirm, NCheckbox } from 'naive-ui'
 import { useI18n } from 'vue-i18n'
 import type { Session } from '@/stores/hermes/chat'
@@ -22,6 +23,49 @@ const emit = defineEmits<{
 }>()
 
 const { t } = useI18n()
+
+let longPressTimer: ReturnType<typeof setTimeout> | null = null
+const longPressTriggered = ref(false)
+
+function onTouchStart(e: TouchEvent) {
+  longPressTriggered.value = false
+  longPressTimer = setTimeout(() => {
+    longPressTriggered.value = true
+    const touch = e.touches[0]
+    const syntheticEvent = new MouseEvent('contextmenu', {
+      clientX: touch.clientX,
+      clientY: touch.clientY,
+      bubbles: true,
+    })
+    emit('contextmenu', syntheticEvent)
+  }, 500)
+}
+
+function onTouchEnd() {
+  if (longPressTimer) {
+    clearTimeout(longPressTimer)
+    longPressTimer = null
+  }
+}
+
+function onTouchMove() {
+  if (longPressTimer) {
+    clearTimeout(longPressTimer)
+    longPressTimer = null
+  }
+}
+
+function onClick() {
+  if (longPressTriggered.value) {
+    longPressTriggered.value = false
+    return
+  }
+  emit('select')
+}
+
+onUnmounted(() => {
+  if (longPressTimer) clearTimeout(longPressTimer)
+})
 </script>
 
 <template>
@@ -29,8 +73,11 @@ const { t } = useI18n()
     class="session-item"
     :class="{ active, 'batch-mode': selectable }"
     :aria-current="active ? 'page' : undefined"
-    @click="emit('select')"
+    @click="onClick"
     @contextmenu="emit('contextmenu', $event)"
+    @touchstart="onTouchStart"
+    @touchend="onTouchEnd"
+    @touchmove="onTouchMove"
   >
     <div v-if="selectable" class="session-item-checkbox">
       <NCheckbox :checked="selected" @click.stop="emit('toggle-select')" />
diff --git a/packages/client/src/i18n/locales/de.ts b/packages/client/src/i18n/locales/de.ts
index bf6cb8f..050cb3f 100644
--- a/packages/client/src/i18n/locales/de.ts
+++ b/packages/client/src/i18n/locales/de.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: 'Benutzer',
     monitorRoleAssistant: 'Assistent',
     copySessionId: 'Sitzungs-ID kopieren',
+    export: 'Exportieren',
+    exportFull: 'Vollständiger Export (JSON)',
+    exportCompressed: 'Komprimierter Export (TXT)',
+    exportCompressing: 'Komprimiere Kontext, bitte warten...',
+    exportSuccess: 'Sitzung exportiert',
+    exportFailed: 'Export fehlgeschlagen',
     renamed: 'Umbenannt',
     renameFailed: 'Umbenennung fehlgeschlagen',
     renameSession: 'Sitzung umbenennen',
diff --git a/packages/client/src/i18n/locales/en.ts b/packages/client/src/i18n/locales/en.ts
index e81a330..5190a6b 100644
--- a/packages/client/src/i18n/locales/en.ts
+++ b/packages/client/src/i18n/locales/en.ts
@@ -174,6 +174,12 @@ export default {
     monitorRoleUser: 'User',
     monitorRoleAssistant: 'Assistant',
     copySessionId: 'Copy Session ID',
+    export: 'Export',
+    exportFull: 'Full Export (JSON)',
+    exportCompressed: 'Compressed Export (TXT)',
+    exportCompressing: 'Compressing context, please wait...',
+    exportSuccess: 'Session exported',
+    exportFailed: 'Export failed',
     renamed: 'Renamed',
     renameFailed: 'Rename failed',
     renameSession: 'Rename Session',
diff --git a/packages/client/src/i18n/locales/es.ts b/packages/client/src/i18n/locales/es.ts
index 9aefd21..7e4958f 100644
--- a/packages/client/src/i18n/locales/es.ts
+++ b/packages/client/src/i18n/locales/es.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: 'Usuario',
     monitorRoleAssistant: 'Asistente',
     copySessionId: 'Copiar ID de sesión',
+    export: 'Exportar',
+    exportFull: 'Exportación completa (JSON)',
+    exportCompressed: 'Exportación comprimida (TXT)',
+    exportCompressing: 'Comprimiendo contexto, espere...',
+    exportSuccess: 'Sesión exportada',
+    exportFailed: 'Error al exportar',
     renamed: 'Renombrada',
     renameFailed: 'Error al renombrar',
     renameSession: 'Renombrar sesion',
diff --git a/packages/client/src/i18n/locales/fr.ts b/packages/client/src/i18n/locales/fr.ts
index 7294a51..d5665be 100644
--- a/packages/client/src/i18n/locales/fr.ts
+++ b/packages/client/src/i18n/locales/fr.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: 'Utilisateur',
     monitorRoleAssistant: 'Assistant',
     copySessionId: "Copier l'ID de session",
+    export: 'Exporter',
+    exportFull: 'Export complet (JSON)',
+    exportCompressed: 'Export compressé (TXT)',
+    exportCompressing: 'Compression du contexte, veuillez patienter...',
+    exportSuccess: 'Session exportée',
+    exportFailed: "Échec de l'export",
     renamed: 'Renomme',
     renameFailed: 'Echec du renommage',
     renameSession: 'Renommer la session',
diff --git a/packages/client/src/i18n/locales/ja.ts b/packages/client/src/i18n/locales/ja.ts
index 354e80e..ebdf9f8 100644
--- a/packages/client/src/i18n/locales/ja.ts
+++ b/packages/client/src/i18n/locales/ja.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: 'ユーザー',
     monitorRoleAssistant: 'アシスタント',
     copySessionId: 'セッション ID をコピー',
+    export: 'エクスポート',
+    exportFull: 'フルエクスポート (JSON)',
+    exportCompressed: '圧縮エクスポート (TXT)',
+    exportCompressing: 'コンテキストを圧縮中、お待ちください...',
+    exportSuccess: 'セッションをエクスポートしました',
+    exportFailed: 'エクスポートに失敗しました',
     renamed: '名前を変更しました',
     renameFailed: '名前の変更に失敗しました',
     renameSession: 'セッション名の変更',
diff --git a/packages/client/src/i18n/locales/ko.ts b/packages/client/src/i18n/locales/ko.ts
index 4fff1ad..d416978 100644
--- a/packages/client/src/i18n/locales/ko.ts
+++ b/packages/client/src/i18n/locales/ko.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: '사용자',
     monitorRoleAssistant: '어시스턴트',
     copySessionId: '세션 ID 복사',
+    export: '내보내기',
+    exportFull: '전체 내보내기 (JSON)',
+    exportCompressed: '압축 내보내기 (TXT)',
+    exportCompressing: '컨텍스트 압축 중, 잠시 기다려주세요...',
+    exportSuccess: '세션을 내보냈습니다',
+    exportFailed: '내보내기 실패',
     renamed: '이름이 변경되었습니다',
     renameFailed: '이름 변경 실패',
     renameSession: '세션 이름 변경',
diff --git a/packages/client/src/i18n/locales/pt.ts b/packages/client/src/i18n/locales/pt.ts
index e439f92..2e4ef12 100644
--- a/packages/client/src/i18n/locales/pt.ts
+++ b/packages/client/src/i18n/locales/pt.ts
@@ -151,6 +151,12 @@ export default {
     monitorRoleUser: 'Usuário',
     monitorRoleAssistant: 'Assistente',
     copySessionId: 'Copiar ID da sessão',
+    export: 'Exportar',
+    exportFull: 'Exportação completa (JSON)',
+    exportCompressed: 'Exportação comprimida (TXT)',
+    exportCompressing: 'Comprimindo contexto, aguarde...',
+    exportSuccess: 'Sessão exportada',
+    exportFailed: 'Falha ao exportar',
     renamed: 'Renomeado',
     renameFailed: 'Falha ao renomear',
     renameSession: 'Renomear sessao',
diff --git a/packages/client/src/i18n/locales/zh.ts b/packages/client/src/i18n/locales/zh.ts
index daee383..d24adf9 100644
--- a/packages/client/src/i18n/locales/zh.ts
+++ b/packages/client/src/i18n/locales/zh.ts
@@ -174,6 +174,12 @@ export default {
     monitorRoleUser: '用户',
     monitorRoleAssistant: '助手',
     copySessionId: '复制会话 ID',
+    export: '导出',
+    exportFull: '全量导出 (JSON)',
+    exportCompressed: '压缩导出 (TXT)',
+    exportCompressing: '正在压缩上下文，请稍候...',
+    exportSuccess: '会话已导出',
+    exportFailed: '导出失败',
     renamed: '已重命名',
     renameFailed: '重命名失败',
     renameSession: '重命名会话',
diff --git a/packages/client/src/views/hermes/HistoryView.vue b/packages/client/src/views/hermes/HistoryView.vue
index d2c5174..0273670 100644
--- a/packages/client/src/views/hermes/HistoryView.vue
+++ b/packages/client/src/views/hermes/HistoryView.vue
@@ -11,7 +11,7 @@ import { copyToClipboard } from '@/utils/clipboard'
 import FolderPicker from '@/components/hermes/chat/FolderPicker.vue'
 import HistoryMessageList from '@/components/hermes/chat/HistoryMessageList.vue'
 import SessionListItem from '@/components/hermes/chat/SessionListItem.vue'
-import { renameSession, setSessionWorkspace, fetchHermesSessions, fetchHermesSession, type SessionSummary } from '@/api/hermes/sessions'
+import { renameSession, setSessionWorkspace, fetchHermesSessions, fetchHermesSession, exportSession, type SessionSummary } from '@/api/hermes/sessions'
 
 const chatStore = useChatStore()
 const appStore = useAppStore()
@@ -281,6 +281,28 @@ const contextMenuOptions = computed(() => [
   { label: t(contextSessionPinned.value ? 'chat.unpin' : 'chat.pin'), key: 'pin' },
   { label: t('chat.rename'), key: 'rename' },
   { label: t('chat.setWorkspace'), key: 'workspace' },
+  {
+    label: t('chat.export'),
+    key: 'export',
+    children: [
+      {
+        label: t('chat.exportFull'),
+        key: 'export-full',
+        children: [
+          { label: 'JSON', key: 'export-full-json' },
+          { label: 'TXT', key: 'export-full-txt' },
+        ],
+      },
+      {
+        label: t('chat.exportCompressed'),
+        key: 'export-compressed',
+        children: [
+          { label: 'JSON', key: 'export-compressed-json' },
+          { label: 'TXT', key: 'export-compressed-txt' },
+        ],
+      },
+    ],
+  },
   { label: t('chat.copySessionId'), key: 'copy-id' },
 ])
 
@@ -296,7 +318,15 @@ const showContextMenu = ref(false)
 const contextMenuX = ref(0)
 const contextMenuY = ref(0)
 
-function handleContextMenuSelect(key: string) {
+function parseExportKey(key: string): { mode: 'full' | 'compressed'; ext: 'json' | 'txt' } | null {
+  if (key === 'export-full-json') return { mode: 'full', ext: 'json' }
+  if (key === 'export-full-txt') return { mode: 'full', ext: 'txt' }
+  if (key === 'export-compressed-json') return { mode: 'compressed', ext: 'json' }
+  if (key === 'export-compressed-txt') return { mode: 'compressed', ext: 'txt' }
+  return null
+}
+
+async function handleContextMenuSelect(key: string) {
   showContextMenu.value = false
   if (!contextSessionId.value) return
   if (key === 'pin') {
@@ -305,6 +335,17 @@ function handleContextMenuSelect(key: string) {
   }
   if (key === 'copy-id') {
     copySessionId(contextSessionId.value)
+  } else if (parseExportKey(key)) {
+    const { mode, ext } = parseExportKey(key)!
+    const loadingMsg = mode === 'compressed' ? message.loading(t('chat.exportCompressing'), { duration: 0 }) : null
+    try {
+      await exportSession(contextSessionId.value, mode, ext)
+      loadingMsg?.destroy()
+      message.success(t('chat.exportSuccess'))
+    } catch {
+      loadingMsg?.destroy()
+      message.error(t('chat.exportFailed'))
+    }
   } else if (key === 'workspace') {
     const session = historySessions.value.find(s => s.id === contextSessionId.value)
     workspaceSessionId.value = contextSessionId.value
diff --git a/packages/server/src/controllers/hermes/sessions.ts b/packages/server/src/controllers/hermes/sessions.ts
index a22e02a..f70a9b6 100644
--- a/packages/server/src/controllers/hermes/sessions.ts
+++ b/packages/server/src/controllers/hermes/sessions.ts
@@ -10,6 +10,8 @@ import {
   renameSession as localRenameSession,
   useLocalSessionStore,
 } from '../../db/hermes/session-store'
+import { ExportCompressor } from '../../lib/context-compressor/export-compressor'
+import { getGatewayManagerInstance } from '../../services/gateway-bootstrap'
 import { deleteUsage, getUsage, getUsageBatch, getLocalUsageStats } from '../../db/hermes/usage-store'
 import type { LocalUsageStats, UsageStatsModelRow, UsageStatsDailyRow } from '../../db/hermes/usage-store'
 import { getModelContextLength } from '../../services/hermes/model-context'
@@ -539,6 +541,90 @@ export async function listWorkspaceFolders(ctx: any) {
   }
 }
 
+const exportCompressor = new ExportCompressor()
+
+export async function exportSession(ctx: any) {
+  let session: any = null
+
+  if (useLocalSessionStore()) {
+    session = localGetSessionDetail(ctx.params.id)
+  } else {
+    try {
+      session = await getSessionDetailFromDb(ctx.params.id)
+    } catch (err) {
+      logger.warn(err, 'Hermes Session DB: export detail query failed, falling back to CLI')
+    }
+    if (!session) {
+      session = await hermesCli.getSession(ctx.params.id)
+    }
+  }
+
+  if (!session) {
+    ctx.status = 404
+    ctx.body = { error: 'Session not found' }
+    return
+  }
+
+  const mode = (ctx.query.mode as string) || 'full'
+  const ext = (ctx.query.ext as string) || (mode === 'compressed' ? 'txt' : 'json')
+  const title = session.title || 'session'
+  const safeName = title.replace(/[^a-zA-Z0-9一-鿿_-]/g, '_').slice(0, 50)
+  const filename = `${safeName}_${ctx.params.id.slice(0, 8)}.${ext}`
+
+  if (mode === 'compressed') {
+    const result = await compressSession(session)
+    if (ext === 'json') {
+      ctx.set('Content-Disposition', `attachment; filename="${encodeURIComponent(filename)}"`)
+      ctx.set('Content-Type', 'application/json')
+      ctx.body = JSON.stringify({ id: session.id, title: session.title, ...result.meta, messages: result.messages }, null, 2)
+    } else {
+      ctx.set('Content-Disposition', `attachment; filename="${encodeURIComponent(filename)}"`)
+      ctx.set('Content-Type', 'text/plain; charset=utf-8')
+      ctx.body = serializeAsText(session.title, result.messages)
+    }
+  } else {
+    if (ext === 'txt') {
+      ctx.set('Content-Disposition', `attachment; filename="${encodeURIComponent(filename)}"`)
+      ctx.set('Content-Type', 'text/plain; charset=utf-8')
+      ctx.body = serializeAsText(session.title, session.messages || [])
+    } else {
+      ctx.set('Content-Disposition', `attachment; filename="${encodeURIComponent(filename)}"`)
+      ctx.set('Content-Type', 'application/json')
+      ctx.body = JSON.stringify(session, null, 2)
+    }
+  }
+}
+
+async function compressSession(session: any) {
+  const mgr = getGatewayManagerInstance()
+  const profile = getActiveProfileName()
+  const upstream = mgr ? mgr.getUpstream(profile).replace(/\/$/, '') : ''
+  const apiKey = mgr ? mgr.getApiKey(profile) || undefined : undefined
+  const messages = (session.messages || []).map((m: any) => ({
+    role: m.role,
+    content: m.content || '',
+    tool_calls: m.tool_calls,
+    tool_call_id: m.tool_call_id,
+    name: m.tool_name,
+    reasoning_content: m.reasoning,
+  }))
+
+  return exportCompressor.compress(messages, upstream, apiKey, session.id, profile)
+}
+
+function serializeAsText(title: string | null, messages: any[]): string {
+  const lines: string[] = [`# ${title || 'Untitled'}`, '']
+  for (const msg of messages) {
+    const role = msg.role || 'unknown'
+    const content = typeof msg.content === 'string' ? msg.content : JSON.stringify(msg.content)
+    const ts = msg.timestamp ? new Date(msg.timestamp * 1000).toISOString() : ''
+    lines.push(`[${role}]${ts ? ' ' + ts : ''}`)
+    lines.push(content || '')
+    lines.push('')
+  }
+  return lines.join('\n')
+}
+
 export async function getConversationMessagesPaginated(ctx: any) {
   const offset = ctx.query.offset ? parseInt(ctx.query.offset as string, 10) : 0
   const limit = ctx.query.limit ? parseInt(ctx.query.limit as string, 10) : 50
diff --git a/packages/server/src/lib/context-compressor/export-compressor.ts b/packages/server/src/lib/context-compressor/export-compressor.ts
new file mode 100644
index 0000000..e81e11b
--- /dev/null
+++ b/packages/server/src/lib/context-compressor/export-compressor.ts
@@ -0,0 +1,149 @@
+/**
+ * Export Compressor
+ *
+ * Compresses session context for export purposes.
+ * Reuses the LLM summarization logic from ChatContextCompressor
+ * but does NOT read or write compression snapshots.
+ * Always forces LLM compression regardless of token count.
+ * No tail reservation — all messages are compressed.
+ */
+
+import { logger } from '../../services/logger'
+import {
+  type ChatMessage,
+  type CompressionConfig,
+  type CompressedResult,
+  DEFAULT_COMPRESSION_CONFIG,
+  countTokens,
+  serializeForSummary,
+  buildFullPrompt,
+  buildIncrementalPrompt,
+  buildConversationHistory,
+  callSummarizer,
+} from './index'
+import { getCompressionSnapshot } from '../../db/hermes/compression-snapshot'
+
+export class ExportCompressor {
+  private config: CompressionConfig
+
+  constructor(opts?: { config?: Partial<CompressionConfig> }) {
+    this.config = { ...DEFAULT_COMPRESSION_CONFIG, ...opts?.config }
+  }
+
+  async compress(
+    messages: ChatMessage[],
+    upstream: string,
+    apiKey: string | undefined,
+    sessionId?: string,
+    profile?: string,
+  ): Promise<CompressedResult> {
+    const total = messages.length
+
+    const meta: CompressedResult['meta'] = {
+      totalMessages: total,
+      compressed: false,
+      llmCompressed: false,
+      summaryTokenEstimate: 0,
+      verbatimCount: 0,
+      compressedStartIndex: -1,
+    }
+
+    // Read snapshot for incremental context, but never write
+    const snapshot = sessionId ? getCompressionSnapshot(sessionId) : null
+
+    if (snapshot) {
+      logger.info(
+        '[export-compressor] session=%s: incremental compress with existing snapshot at index %d',
+        sessionId, snapshot.lastMessageIndex,
+      )
+      return this.incrementalCompress(
+        messages, snapshot, upstream, apiKey, meta, profile,
+      )
+    }
+
+    logger.info(
+      '[export-compressor] session=%s: full compress %d messages',
+      sessionId, total,
+    )
+    return this.fullCompress(messages, upstream, apiKey, meta, profile)
+  }
+
+  private async incrementalCompress(
+    messages: ChatMessage[],
+    snapshot: { summary: string; lastMessageIndex: number },
+    upstream: string,
+    apiKey: string | undefined,
+    meta: CompressedResult['meta'],
+    profile?: string,
+  ): Promise<CompressedResult> {
+    const { summary: previousSummary, lastMessageIndex } = snapshot
+    const newMessages = messages.slice(lastMessageIndex + 1)
+
+    let summary: string | null = null
+    try {
+      const contentToSummarize = serializeForSummary(newMessages)
+      const prompt = buildIncrementalPrompt(previousSummary, contentToSummarize, this.config.summaryBudget)
+      const history = buildConversationHistory(newMessages)
+
+      const t0 = Date.now()
+      summary = await callSummarizer(upstream, apiKey, prompt, history, this.config.summarizationTimeoutMs, previousSummary, profile)
+      logger.info('[export-compressor] incremental-llm done in %dms, %d chars', Date.now() - t0, summary!.length)
+    } catch (err: any) {
+      logger.warn('[export-compressor] incremental-llm failed: %s — reusing previous summary', err.message)
+      summary = previousSummary
+    }
+
+    const summaryText = summary || previousSummary
+
+    return {
+      messages: [{ role: 'user', content: summaryText }],
+      meta: {
+        ...meta,
+        compressed: true,
+        llmCompressed: true,
+        summaryTokenEstimate: countTokens(summaryText),
+        verbatimCount: 0,
+      },
+    }
+  }
+
+  private async fullCompress(
+    messages: ChatMessage[],
+    upstream: string,
+    apiKey: string | undefined,
+    meta: CompressedResult['meta'],
+    profile?: string,
+  ): Promise<CompressedResult> {
+    if (messages.length === 0) {
+      return { messages: [], meta }
+    }
+
+    let summary: string | null = null
+    try {
+      const contentToSummarize = serializeForSummary(messages)
+      const prompt = buildFullPrompt(contentToSummarize, this.config.summaryBudget)
+      const history = buildConversationHistory(messages)
+
+      const t0 = Date.now()
+      summary = await callSummarizer(upstream, apiKey, prompt, history, this.config.summarizationTimeoutMs, undefined, profile)
+      logger.info('[export-compressor] full-llm done in %dms, %d chars', Date.now() - t0, summary!.length)
+    } catch (err: any) {
+      logger.warn('[export-compressor] full-llm failed: %s', err.message)
+    }
+
+    if (!summary) {
+      return { messages, meta }
+    }
+
+    return {
+      messages: [{ role: 'user', content: summary }],
+      meta: {
+        ...meta,
+        compressed: true,
+        llmCompressed: true,
+        summaryTokenEstimate: countTokens(summary),
+        verbatimCount: 0,
+      },
+    }
+  }
+}
diff --git a/packages/server/src/lib/context-compressor/index.ts b/packages/server/src/lib/context-compressor/index.ts
index d37f2d8..8b8bba3 100644
--- a/packages/server/src/lib/context-compressor/index.ts
+++ b/packages/server/src/lib/context-compressor/index.ts
@@ -172,7 +172,7 @@ Be specific with file paths, commands, line numbers, and results.]
 ## Critical Context
 [Any specific values, error messages, configuration details, or data that would be lost without explicit preservation]`
 
-function buildFullPrompt(contentToSummarize: string, summaryBudget: number): string {
+export function buildFullPrompt(contentToSummarize: string, summaryBudget: number): string {
   return `You are a summarization agent creating a context checkpoint.
 Your output will be injected as reference material for a DIFFERENT
 assistant that continues the conversation.
@@ -194,7 +194,7 @@ Target ~${summaryBudget} tokens. Be CONCRETE — include file paths, command out
 Write only the summary body. Do not include any preamble or prefix.`
 }
 
-function buildIncrementalPrompt(previousSummary: string, contentToSummarize: string, summaryBudget: number): string {
+export function buildIncrementalPrompt(previousSummary: string, contentToSummarize: string, summaryBudget: number): string {
   return `You are a summarization agent creating a context checkpoint.
 Your output will be injected as reference material for a DIFFERENT
 assistant that continues the conversation.
@@ -229,7 +229,7 @@ Write only the summary body. Do not include any preamble or prefix.`
 
 // ─── Pre-cleaning ───────────────────────────────────────
 
-function serializeForSummary(messages: ChatMessage[]): string {
+export function serializeForSummary(messages: ChatMessage[]): string {
   const parts: string[] = []
 
   function contentToString(content: string | ContentBlock[]): string {
@@ -272,13 +272,13 @@ function serializeForSummary(messages: ChatMessage[]): string {
  * Convert messages to conversation history format for LLM API.
  * Tool calls are converted to text format within assistant messages.
  */
-function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string; content: string }> {
+export function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string; content: string }> {
   const result: Array<{ role: string; content: string }> = []
 
   for (const msg of messages) {
     if (msg.role === 'tool') {
       // Convert tool result to text and append to previous assistant message
-      const toolText = `[Tool result: ${msg.name || 'unknown'}]\n${(msg.content || '').slice(0, 500)}${msg.content && msg.content.length > 500 ? '...' : ''}`
+      const toolText = `[Tool result: ${msg.name || 'unknown'}]\n${(msg.content || '').slice(0, 4000)}${msg.content && msg.content.length > 4000 ? '...' : ''}`
       // Find the last assistant message and append to it
       const lastAssistant = result.findLast(m => m.role === 'assistant')
       if (lastAssistant) {
@@ -291,7 +291,7 @@ function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string
       // Include tool calls in assistant message
       const toolsInfo = msg.tool_calls.map(tc => {
         let args = tc.function.arguments
-        if (args.length > 1000) args = args.slice(0, 1000) + '...'
+        if (args.length > 4000) args = args.slice(0, 4000) + '...'
         return `[Calling tool: ${tc.function.name} with arguments: ${args}]`
       }).join('\n')
       const content = msg.content ? `${msg.content}\n\n${toolsInfo}` : toolsInfo
@@ -313,6 +313,7 @@ function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string
           }
         }
       }
+      if (contentStr.length > 4000) contentStr = contentStr.slice(0, 4000) + '...'
       result.push({ role: 'user', content: contentStr })
     } else if (msg.role === 'assistant' || msg.role === 'system') {
       let contentStr = ''
@@ -330,6 +331,7 @@ function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string
           }
         }
       }
+      if (contentStr.length > 4000) contentStr = contentStr.slice(0, 4000) + '...'
       result.push({ role: msg.role, content: contentStr })
     }
     // Skip other roles
@@ -338,7 +340,7 @@ function buildConversationHistory(messages: ChatMessage[]): Array<{ role: string
   return result
 }
 
-function pruneOldToolResults(messages: ChatMessage[], keepRecentCount: number): ChatMessage[] {
+export function pruneOldToolResults(messages: ChatMessage[], keepRecentCount: number): ChatMessage[] {
   if (messages.length <= keepRecentCount) return messages
 
   const tail = messages.slice(-keepRecentCount)
@@ -365,7 +367,7 @@ function pruneOldToolResults(messages: ChatMessage[], keepRecentCount: number):
 
 // ─── LLM Summarization ──────────────────────────────────
 
-async function callSummarizer(
+export async function callSummarizer(
   upstream: string,
   apiKey: string | undefined,
   prompt: string,
diff --git a/packages/server/src/routes/hermes/sessions.ts b/packages/server/src/routes/hermes/sessions.ts
index 1f489a0..7768fa1 100644
--- a/packages/server/src/routes/hermes/sessions.ts
+++ b/packages/server/src/routes/hermes/sessions.ts
@@ -15,6 +15,7 @@ sessionRoutes.get('/api/hermes/sessions/usage', ctrl.usageBatch)
 sessionRoutes.get('/api/hermes/usage/stats', ctrl.usageStats)
 sessionRoutes.get('/api/hermes/sessions/context-length', ctrl.contextLength)
 sessionRoutes.get('/api/hermes/sessions/:id', ctrl.get)
+sessionRoutes.get('/api/hermes/sessions/:id/export', ctrl.exportSession)
 sessionRoutes.get('/api/hermes/sessions/:id/usage', ctrl.usageSingle)
 sessionRoutes.delete('/api/hermes/sessions/:id', ctrl.remove)
 sessionRoutes.post('/api/hermes/sessions/batch-delete', ctrl.batchRemove)
diff --git a/tests/server/sessions-controller.test.ts b/tests/server/sessions-controller.test.ts
index a00f07c..f3fb025 100644
--- a/tests/server/sessions-controller.test.ts
+++ b/tests/server/sessions-controller.test.ts
@@ -11,6 +11,7 @@ const getGroupChatServerMock = vi.fn()
 const getLocalUsageStatsMock = vi.fn()
 const getActiveProfileNameMock = vi.fn()
 const loggerWarnMock = vi.fn()
+const getCompressionSnapshotMock = vi.fn()
 
 vi.mock('../../packages/server/src/db/hermes/conversations-db', () => ({
   listConversationSummariesFromDb: listConversationSummariesFromDbMock,
@@ -67,6 +68,25 @@ vi.mock('../../packages/server/src/services/hermes/hermes-profile', () => ({
   getActiveProfileName: getActiveProfileNameMock,
 }))
 
+vi.mock('../../packages/server/src/db/hermes/compression-snapshot', () => ({
+  getCompressionSnapshot: getCompressionSnapshotMock,
+}))
+
+vi.mock('../../packages/server/src/lib/context-compressor/export-compressor', () => ({
+  ExportCompressor: class {
+    async compress(messages: any[]) {
+      return {
+        messages,
+        meta: { totalMessages: messages.length, compressed: true, llmCompressed: true, summaryTokenEstimate: 100, verbatimCount: 0, compressedStartIndex: -1 },
+      }
+    }
+  },
+}))
+
+vi.mock('../../packages/server/src/services/gateway-bootstrap', () => ({
+  getGatewayManagerInstance: () => null,
+}))
+
 describe('session conversations controller', () => {
   beforeEach(() => {
     vi.resetModules()
@@ -83,6 +103,7 @@ describe('session conversations controller', () => {
     getActiveProfileNameMock.mockReset()
     getActiveProfileNameMock.mockReturnValue('default')
     loggerWarnMock.mockReset()
+    getCompressionSnapshotMock.mockReset()
   })
 
   it('prefers the DB-backed conversations summary path', async () => {
@@ -198,4 +219,76 @@ describe('session conversations controller', () => {
       cost: 0.02,
     })
   })
+
+  describe('exportSession', () => {
+    it('returns session as JSON download with correct headers (full mode)', async () => {
+      const sessionData = { id: 'abc-123', title: 'Test Session', messages: [{ id: 1, role: 'user', content: 'hello' }] }
+      getSessionDetailFromDbMock.mockResolvedValue(sessionData)
+
+      const mod = await import('../../packages/server/src/controllers/hermes/sessions')
+      const setMock = vi.fn()
+      const ctx: any = { params: { id: 'abc-123' }, query: {}, set: setMock, body: null }
+
+      await mod.exportSession(ctx)
+
+      expect(getSessionDetailFromDbMock).toHaveBeenCalledWith('abc-123')
+      expect(setMock).toHaveBeenCalledWith('Content-Disposition', expect.stringContaining('abc-123'))
+      expect(setMock).toHaveBeenCalledWith('Content-Type', 'application/json')
+      expect(ctx.status).toBeUndefined()
+      expect(JSON.parse(ctx.body)).toMatchObject({ id: 'abc-123', title: 'Test Session' })
+    })
+
+    it('returns full TXT export', async () => {
+      const sessionData = {
+        id: 'txt-123',
+        title: 'Text Export',
+        messages: [
+          { id: 1, role: 'user', content: 'hello', timestamp: 1700000000 },
+          { id: 2, role: 'assistant', content: 'hi', timestamp: 1700000001 },
+        ],
+      }
+      getSessionDetailFromDbMock.mockResolvedValue(sessionData)
+
+      const mod = await import('../../packages/server/src/controllers/hermes/sessions')
+      const setMock = vi.fn()
+      const ctx: any = { params: { id: 'txt-123' }, query: { mode: 'full', ext: 'txt' }, set: setMock, body: null }
+
+      await mod.exportSession(ctx)
+
+      expect(setMock).toHaveBeenCalledWith('Content-Type', 'text/plain; charset=utf-8')
+      expect(ctx.body).toContain('# Text Export')
+      expect(ctx.body).toContain('[user]')
+      expect(ctx.body).toContain('hello')
+      expect(ctx.body).toContain('[assistant]')
+      expect(ctx.body).toContain('hi')
+    })
+
+    it('returns 404 when session not found', async () => {
+      getSessionDetailFromDbMock.mockResolvedValue(null)
+      getSessionMock.mockResolvedValue(null)
+
+      const mod = await import('../../packages/server/src/controllers/hermes/sessions')
+      const ctx: any = { params: { id: 'not-found' }, query: {}, set: vi.fn(), body: null }
+
+      await mod.exportSession(ctx)
+
+      expect(ctx.status).toBe(404)
+      expect(ctx.body).toEqual({ error: 'Session not found' })
+    })
+
+    it('falls back to CLI when DB query fails', async () => {
+      const sessionData = { id: 'cli-123', title: 'CLI Session', messages: [] }
+      getSessionDetailFromDbMock.mockRejectedValue(new Error('db unavailable'))
+      getSessionMock.mockResolvedValue(sessionData)
+
+      const mod = await import('../../packages/server/src/controllers/hermes/sessions')
+      const setMock = vi.fn()
+      const ctx: any = { params: { id: 'cli-123' }, query: {}, set: setMock, body: null }
+
+      await mod.exportSession(ctx)
+
+      expect(getSessionMock).toHaveBeenCalledWith('cli-123')
+      expect(JSON.parse(ctx.body)).toMatchObject({ id: 'cli-123' })
+    })
+  })
 })
diff --git a/tests/server/sessions-routes.test.ts b/tests/server/sessions-routes.test.ts
index a721c97..9e8211d 100644
--- a/tests/server/sessions-routes.test.ts
+++ b/tests/server/sessions-routes.test.ts
@@ -17,6 +17,7 @@ const usageSingleMock = vi.fn(async (ctx: any) => { ctx.body = { input_tokens: 0
 const usageStatsMock = vi.fn(async (ctx: any) => { ctx.body = { total_input_tokens: 0, total_output_tokens: 0 } })
 const contextLengthMock = vi.fn(async (ctx: any) => { ctx.body = { context_length: 200000 } })
 const batchRemoveMock = vi.fn(async (ctx: any) => { ctx.body = { deleted: 1, failed: 0, errors: [] } })
+const exportSessionMock = vi.fn(async (ctx: any) => { ctx.body = JSON.stringify({ id: ctx.params.id }) })
 
 vi.mock('../../packages/server/src/controllers/hermes/sessions', () => ({
   listConversations: listConversationsMock,
@@ -36,6 +37,7 @@ vi.mock('../../packages/server/src/controllers/hermes/sessions', () => ({
   usageSingle: usageSingleMock,
   usageStats: usageStatsMock,
   contextLength: contextLengthMock,
+  exportSession: exportSessionMock,
 }))
 
 describe('session routes', () => {
@@ -66,6 +68,7 @@ describe('session routes', () => {
       '/api/hermes/usage/stats',
       '/api/hermes/sessions/context-length',
       '/api/hermes/sessions/:id',
+      '/api/hermes/sessions/:id/export',
       '/api/hermes/sessions/:id/usage',
       '/api/hermes/sessions/:id/rename',
     ]))
@@ -110,4 +113,15 @@ describe('session routes', () => {
     expect(getConversationMessagesMock).toHaveBeenCalledWith(detailCtx)
     expect(detailCtx.body).toEqual({ session_id: 'child-session', messages: [] })
   })
+
+  it('delegates session export to the controller', async () => {
+    const { sessionRoutes } = await import('../../packages/server/src/routes/hermes/sessions')
+    const layer = sessionRoutes.stack.find((entry: any) => entry.path === '/api/hermes/sessions/:id/export')
+    const handler = layer.stack[0]
+    const ctx: any = { params: { id: 'session-abc' }, query: {}, body: null, set: vi.fn() }
+
+    await handler(ctx)
+
+    expect(exportSessionMock).toHaveBeenCalledWith(ctx)
+  })
 })