diff --git a/apps/cli/src/http/routes/web/session-index.ts b/apps/cli/src/http/routes/web/session-index.ts
index e6bc6ce5..16a03693 100644
--- a/apps/cli/src/http/routes/web/session-index.ts
+++ b/apps/cli/src/http/routes/web/session-index.ts
@@ -11,6 +11,15 @@ export function registerSessionIndexRoutes(server: FastifyInstance, adapter: Ses
     return { sessionCount }
   })
 
+  server.post<{
+    Params: { id: string }
+    Body: { gapThreshold?: number }
+  }>('/_web/sessions/:id/generate-incremental-index', async (request) => {
+    const gapThreshold = (request.body as any)?.gapThreshold ?? 1800
+    const sessionCount = sessionIndexService.generateIncrementalIndex(adapter, request.params.id, gapThreshold)
+    return { sessionCount }
+  })
+
   server.post<{ Params: { id: string } }>('/_web/sessions/:id/clear-index', async (request) => {
     sessionIndexService.clearIndex(adapter, request.params.id)
     return { success: true }
diff --git a/apps/desktop/main/ipc/chat.ts b/apps/desktop/main/ipc/chat.ts
index 415d3b72..ce6b8ffe 100644
--- a/apps/desktop/main/ipc/chat.ts
+++ b/apps/desktop/main/ipc/chat.ts
@@ -803,6 +803,15 @@ export function registerChatHandlers(ctx: IpcContext): void {
     }
   })
 
+  ipcMain.handle('session:generateIncremental', async (_, sessionId: string, gapThreshold?: number) => {
+    try {
+      return await worker.generateIncrementalSessions(sessionId, gapThreshold)
+    } catch (error) {
+      console.error('Failed to generate incremental session index:', error)
+      throw error
+    }
+  })
+
   /**
    * 检查是否已生成会话索引
    */
diff --git a/apps/desktop/preload/apis/utils.ts b/apps/desktop/preload/apis/utils.ts
index 3437faa2..4932e7de 100644
--- a/apps/desktop/preload/apis/utils.ts
+++ b/apps/desktop/preload/apis/utils.ts
@@ -240,9 +240,10 @@ export const sessionApi = {
     return ipcRenderer.invoke('session:generate', sessionId, gapThreshold)
   },
 
-  /**
-   * 检查是否已生成会话索引
-   */
+  generateIncremental: (sessionId: string, gapThreshold?: number): Promise<number> => {
+    return ipcRenderer.invoke('session:generateIncremental', sessionId, gapThreshold)
+  },
+
   hasIndex: (sessionId: string): Promise<boolean> => {
     return ipcRenderer.invoke('session:hasIndex', sessionId)
   },
diff --git a/apps/desktop/preload/index.d.ts b/apps/desktop/preload/index.d.ts
index 628e0c2f..c319da40 100644
--- a/apps/desktop/preload/index.d.ts
+++ b/apps/desktop/preload/index.d.ts
@@ -1107,6 +1107,7 @@ interface ChatSessionItem {
 
 interface SessionApi {
   generate: (sessionId: string, gapThreshold?: number) => Promise<number>
+  generateIncremental: (sessionId: string, gapThreshold?: number) => Promise<number>
   hasIndex: (sessionId: string) => Promise<boolean>
   getStats: (sessionId: string) => Promise<SessionStats>
   clear: (sessionId: string) => Promise<boolean>
diff --git a/packages/node-runtime/src/services/index.ts b/packages/node-runtime/src/services/index.ts
index 992d04c5..a037c95a 100644
--- a/packages/node-runtime/src/services/index.ts
+++ b/packages/node-runtime/src/services/index.ts
@@ -24,7 +24,14 @@ export {
 export type { MembersPaginatedDTO } from './member-service'
 
 // Session index service
-export { generateIndex, clearIndex, getFtsStatus, searchFts, rebuildFts } from './session-index-service'
+export {
+  generateIndex,
+  generateIncrementalIndex,
+  clearIndex,
+  getFtsStatus,
+  searchFts,
+  rebuildFts,
+} from './session-index-service'
 
 // Summary service
 export { generateSummary, generateAllSummaries } from './summary-service'
diff --git a/packages/node-runtime/src/services/session-index-service.ts b/packages/node-runtime/src/services/session-index-service.ts
index 96f45791..9b2adcd3 100644
--- a/packages/node-runtime/src/services/session-index-service.ts
+++ b/packages/node-runtime/src/services/session-index-service.ts
@@ -6,6 +6,7 @@
 
 import {
   generateSessionIndex as coreGenerateSessionIndex,
+  generateIncrementalSessionIndex as coreGenerateIncrementalSessionIndex,
   clearSessionIndex as coreClearSessionIndex,
 } from '@openchatlab/core'
 import { hasFtsTable, searchByFts, rebuildFtsIndex } from '../fts'
@@ -16,6 +17,15 @@ export function generateIndex(adapter: SessionRuntimeAdapter, sessionId: string,
   return coreGenerateSessionIndex(db, gapThreshold)
 }
 
+export function generateIncrementalIndex(
+  adapter: SessionRuntimeAdapter,
+  sessionId: string,
+  gapThreshold: number = 1800
+): number {
+  const db = adapter.ensureWritable(sessionId)
+  return coreGenerateIncrementalSessionIndex(db, gapThreshold)
+}
+
 export function clearIndex(adapter: SessionRuntimeAdapter, sessionId: string): void {
   const db = adapter.ensureWritable(sessionId)
   coreClearSessionIndex(db)
diff --git a/src/services/session-index/electron.ts b/src/services/session-index/electron.ts
index 6bfc967d..c8c94c14 100644
--- a/src/services/session-index/electron.ts
+++ b/src/services/session-index/electron.ts
@@ -16,6 +16,10 @@ export class ElectronSessionIndexAdapter implements SessionIndexAdapter {
     return window.sessionApi.generate(sessionId, gapThreshold)
   }
 
+  generateIncremental(sessionId: string, gapThreshold?: number): Promise<number> {
+    return window.sessionApi.generateIncremental(sessionId, gapThreshold)
+  }
+
   hasIndex(sessionId: string): Promise<boolean> {
     return window.sessionApi.hasIndex(sessionId)
   }
diff --git a/src/services/session-index/fetch.ts b/src/services/session-index/fetch.ts
index b3efeb94..2791dce4 100644
--- a/src/services/session-index/fetch.ts
+++ b/src/services/session-index/fetch.ts
@@ -33,6 +33,17 @@ export class FetchSessionIndexAdapter implements SessionIndexAdapter {
     return result.sessionCount
   }
 
+  async generateIncremental(sessionId: string, gapThreshold: number = 1800): Promise<number> {
+    const resp = await fetch(`/_web/sessions/${sessionId}/generate-incremental-index`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ gapThreshold }),
+    })
+    if (!resp.ok) throw new Error(`Failed to generate incremental session index: ${resp.status}`)
+    const result = (await resp.json()) as { sessionCount: number }
+    return result.sessionCount
+  }
+
   async hasIndex(sessionId: string): Promise<boolean> {
     const stats = await this.getStats(sessionId)
     return stats.hasIndex
diff --git a/src/services/session-index/types.ts b/src/services/session-index/types.ts
index c6a246d4..51135fa5 100644
--- a/src/services/session-index/types.ts
+++ b/src/services/session-index/types.ts
@@ -39,6 +39,7 @@ export interface CanGenerateInfo {
 
 export interface SessionIndexAdapter {
   generate(sessionId: string, gapThreshold?: number): Promise<number>
+  generateIncremental(sessionId: string, gapThreshold?: number): Promise<number>
   hasIndex(sessionId: string): Promise<boolean>
   getStats(sessionId: string): Promise<SessionStats>
   clear(sessionId: string): Promise<boolean>
diff --git a/src/stores/apiServer.ts b/src/stores/apiServer.ts
index 71e808b4..ebefd36e 100644
--- a/src/stores/apiServer.ts
+++ b/src/stores/apiServer.ts
@@ -526,7 +526,7 @@ export const useApiServerStore = defineStore('apiServer', () => {
     const indexService = useSessionIndexService()
     const threshold = getSessionGapThreshold()
     for (const sess of targets) {
-      indexService.generate(sess.targetSessionId, threshold).catch(() => {})
+      indexService.generateIncremental(sess.targetSessionId, threshold).catch(() => {})
     }
   }
 
@@ -536,7 +536,7 @@ export const useApiServerStore = defineStore('apiServer', () => {
     for (const ds of dataSources.value) {
       for (const sess of ds.sessions) {
         if (sess.targetSessionId) {
-          indexService.generate(sess.targetSessionId, threshold).catch(() => {})
+          indexService.generateIncremental(sess.targetSessionId, threshold).catch(() => {})
         }
       }
     }