diff --git a/electron/main/worker/query/fts.ts b/electron/main/worker/query/fts.ts
index c0a7f28f..0c68ed3b 100644
--- a/electron/main/worker/query/fts.ts
+++ b/electron/main/worker/query/fts.ts
@@ -1,30 +1,22 @@
 /**
- * FTS5 全文搜索索引管理模块
+ * FTS5 full-text search index management — Electron adapter layer.
  *
- * 使用 Contentless FTS5 虚拟表为 message.content 提供倒排索引。
- * 通过应用层预分词（jieba + Intl.Segmenter），空格分隔后存入 FTS5。
- *
- * DELETE 策略：不在 FTS 做同步删除，依赖 JOIN message 自然过滤。
- * 提供 rebuildFtsIndex() 用于手动清理无效条目。
+ * Core FTS operations are delegated to @openchatlab/node-runtime.
+ * This module adds session-level DB connection management.
  */
 
 import Database from 'better-sqlite3'
+import { BetterSqliteAdapter } from '@openchatlab/node-runtime'
+import {
+  hasFtsTable,
+  createFtsTable as coreCreateFtsTable,
+  buildFtsIndex as coreBuildFtsIndex,
+  rebuildFtsIndex as coreRebuildFtsIndex,
+  insertFtsEntries as coreInsertFtsEntries,
+  searchByFts as coreSearchByFts,
+} from '@openchatlab/node-runtime'
 import { getDbPath, openDatabase } from '../core'
-import { tokenizeForFts, tokenizeQueryForFts } from '../../nlp/ftsTokenizer'
 
-const BATCH_SIZE = 5000
-
-const CREATE_FTS_TABLE_SQL = `
-  CREATE VIRTUAL TABLE IF NOT EXISTS message_fts USING fts5(
-    content,
-    content='',
-    content_rowid=id
-  )
-`
-
-/**
- * 打开可写数据库（FTS 写入专用，不使用缓存池）
- */
 function openWritableDb(sessionId: string): Database.Database | null {
   const dbPath = getDbPath(sessionId)
   try {
@@ -36,171 +28,63 @@ function openWritableDb(sessionId: string): Database.Database | null {
   }
 }
 
-/**
- * 检查数据库是否已有 FTS 索引
- */
 export function hasFtsIndex(sessionId: string): boolean {
   const db = openDatabase(sessionId)
   if (!db) return false
   try {
-    const row = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='message_fts'").get() as
-      | { name: string }
-      | undefined
-    return !!row
+    return hasFtsTable(new BetterSqliteAdapter(db))
   } catch {
     return false
   }
 }
 
-/**
- * 创建 FTS 虚拟表（如果不存在）
- */
 export function createFtsTable(db: Database.Database): void {
-  db.exec(CREATE_FTS_TABLE_SQL)
+  coreCreateFtsTable(new BetterSqliteAdapter(db))
 }
 
-/**
- * 批量构建 FTS 索引（分批处理，每批 BATCH_SIZE 条）
- * 用于迁移或首次导入后的全量构建。
- */
 export function buildFtsIndex(sessionId: string): { indexed: number } {
   const db = openWritableDb(sessionId)
   if (!db) return { indexed: 0 }
 
   try {
-    createFtsTable(db)
-
-    const insertFts = db.prepare('INSERT INTO message_fts(rowid, content) VALUES (?, ?)')
-
-    const countRow = db
-      .prepare("SELECT COUNT(*) as total FROM message WHERE type = 0 AND content IS NOT NULL AND content != ''")
-      .get() as { total: number }
-    const total = countRow.total
-
-    let indexed = 0
-    let offset = 0
-
-    while (offset < total) {
-      const rows = db
-        .prepare(
-          `SELECT id, content FROM message
-           WHERE type = 0 AND content IS NOT NULL AND content != ''
-           ORDER BY id ASC
-           LIMIT ? OFFSET ?`
-        )
-        .all(BATCH_SIZE, offset) as Array<{ id: number; content: string }>
-
-      if (rows.length === 0) break
-
-      const batchInsert = db.transaction(() => {
-        for (const row of rows) {
-          const tokens = tokenizeForFts(row.content)
-          if (tokens) {
-            insertFts.run(row.id, tokens)
-          }
-        }
-      })
-      batchInsert()
-
-      indexed += rows.length
-      offset += BATCH_SIZE
-    }
-
-    return { indexed }
+    return coreBuildFtsIndex(new BetterSqliteAdapter(db))
   } finally {
     db.close()
   }
 }
 
-/**
- * 重建 FTS 索引（清空后重新构建）
- * 用于清理无效条目（如删除成员后）或修复索引
- */
 export function rebuildFtsIndex(sessionId: string): { indexed: number } {
   const db = openWritableDb(sessionId)
   if (!db) return { indexed: 0 }
 
   try {
-    const hasTable = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='message_fts'").get()
-
-    if (hasTable) {
-      db.exec('DROP TABLE message_fts')
-    }
-
-    db.close()
-
-    return buildFtsIndex(sessionId)
-  } catch {
+    return coreRebuildFtsIndex(new BetterSqliteAdapter(db))
+  } finally {
     db.close()
-    return { indexed: 0 }
   }
 }
 
-/**
- * 批量写入 FTS 条目
- * 用于增量导入时同步写入
- */
 export function insertFtsEntries(sessionId: string, entries: Array<{ id: number; content: string | null }>): void {
   const db = openWritableDb(sessionId)
   if (!db) return
 
   try {
-    const hasTable = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='message_fts'").get()
-    if (!hasTable) {
-      db.close()
-      return
-    }
-
-    const insertFts = db.prepare('INSERT INTO message_fts(rowid, content) VALUES (?, ?)')
-
-    const batchInsert = db.transaction(() => {
-      for (const entry of entries) {
-        if (entry.content) {
-          const tokens = tokenizeForFts(entry.content)
-          if (tokens) {
-            insertFts.run(entry.id, tokens)
-          }
-        }
-      }
-    })
-    batchInsert()
+    coreInsertFtsEntries(new BetterSqliteAdapter(db), entries)
   } finally {
     db.close()
   }
 }
 
-/**
- * 通过 FTS5 搜索消息，返回匹配的 message rowids
- */
 export function searchByFts(
   sessionId: string,
   keywords: string[],
-  limit: number = 1000,
-  offset: number = 0
+  limit = 1000,
+  offset = 0
 ): { rowids: number[]; total: number } {
   if (keywords.length === 0) return { rowids: [], total: 0 }
 
   const db = openDatabase(sessionId)
   if (!db) return { rowids: [], total: 0 }
 
-  const matchQuery = tokenizeQueryForFts(keywords)
-  if (!matchQuery) return { rowids: [], total: 0 }
-
-  try {
-    const countRow = db.prepare('SELECT COUNT(*) as total FROM message_fts WHERE content MATCH ?').get(matchQuery) as {
-      total: number
-    }
-
-    const rows = db
-      .prepare(`SELECT rowid FROM message_fts WHERE content MATCH ? ORDER BY rank LIMIT ? OFFSET ?`)
-      .all(matchQuery, limit, offset) as Array<{ rowid: number }>
-
-    return {
-      rowids: rows.map((r) => r.rowid),
-      total: countRow.total,
-    }
-  } catch (error) {
-    console.error('[FTS] Search failed, query:', matchQuery, error)
-    return { rowids: [], total: 0 }
-  }
+  return coreSearchByFts(new BetterSqliteAdapter(db), keywords, limit, offset)
 }
diff --git a/packages/node-runtime/src/fts/index.ts b/packages/node-runtime/src/fts/index.ts
new file mode 100644
index 00000000..64984c78
--- /dev/null
+++ b/packages/node-runtime/src/fts/index.ts
@@ -0,0 +1,140 @@
+/**
+ * FTS5 full-text search index operations (platform-agnostic).
+ *
+ * Extracted from electron/main/worker/query/fts.ts.
+ * Works with DatabaseAdapter + NLP tokenizer from this package.
+ */
+
+import type { DatabaseAdapter } from '@openchatlab/core'
+import { FTS_TABLE_SCHEMA } from '@openchatlab/core'
+import { tokenizeForFts, tokenizeQueryForFts } from '../nlp'
+
+const BATCH_SIZE = 5000
+
+/**
+ * Check if FTS virtual table exists in the database.
+ */
+export function hasFtsTable(db: DatabaseAdapter): boolean {
+  try {
+    const row = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name='message_fts'").get()
+    return !!row
+  } catch {
+    return false
+  }
+}
+
+/**
+ * Create FTS virtual table if it doesn't exist.
+ */
+export function createFtsTable(db: DatabaseAdapter): void {
+  db.exec(FTS_TABLE_SCHEMA)
+}
+
+/**
+ * Build FTS index from all text messages in the database.
+ * Processes in batches for memory efficiency.
+ */
+export function buildFtsIndex(db: DatabaseAdapter): { indexed: number } {
+  createFtsTable(db)
+
+  const insertFts = db.prepare('INSERT INTO message_fts(rowid, content) VALUES (?, ?)')
+
+  const countRow = db
+    .prepare("SELECT COUNT(*) as total FROM message WHERE type = 0 AND content IS NOT NULL AND content != ''")
+    .get() as { total: number } | undefined
+  const total = countRow?.total ?? 0
+
+  let indexed = 0
+  let offset = 0
+
+  while (offset < total) {
+    const rows = db
+      .prepare(
+        `SELECT id, content FROM message
+         WHERE type = 0 AND content IS NOT NULL AND content != ''
+         ORDER BY id ASC LIMIT ? OFFSET ?`
+      )
+      .all(BATCH_SIZE, offset) as Array<{ id: number; content: string }>
+
+    if (rows.length === 0) break
+
+    db.transaction(() => {
+      for (const row of rows) {
+        const tokens = tokenizeForFts(row.content)
+        if (tokens) {
+          insertFts.run(row.id, tokens)
+        }
+      }
+    })
+
+    indexed += rows.length
+    offset += BATCH_SIZE
+  }
+
+  return { indexed }
+}
+
+/**
+ * Rebuild FTS index by dropping and recreating.
+ */
+export function rebuildFtsIndex(db: DatabaseAdapter): { indexed: number } {
+  if (hasFtsTable(db)) {
+    db.exec('DROP TABLE message_fts')
+  }
+  return buildFtsIndex(db)
+}
+
+/**
+ * Insert FTS entries for a batch of messages.
+ * Used during incremental import to sync new messages.
+ */
+export function insertFtsEntries(db: DatabaseAdapter, entries: Array<{ id: number; content: string | null }>): void {
+  if (!hasFtsTable(db)) return
+
+  const insertFts = db.prepare('INSERT INTO message_fts(rowid, content) VALUES (?, ?)')
+
+  db.transaction(() => {
+    for (const entry of entries) {
+      if (entry.content) {
+        const tokens = tokenizeForFts(entry.content)
+        if (tokens) {
+          insertFts.run(entry.id, tokens)
+        }
+      }
+    }
+  })
+}
+
+/**
+ * Search messages using FTS5, returning matching rowids.
+ */
+export function searchByFts(
+  db: DatabaseAdapter,
+  keywords: string[],
+  limit = 1000,
+  offset = 0
+): { rowids: number[]; total: number } {
+  if (keywords.length === 0) return { rowids: [], total: 0 }
+
+  const matchQuery = tokenizeQueryForFts(keywords)
+  if (!matchQuery) return { rowids: [], total: 0 }
+
+  try {
+    const countRow = db.prepare('SELECT COUNT(*) as total FROM message_fts WHERE content MATCH ?').get(matchQuery) as
+      | { total: number }
+      | undefined
+    const total = countRow?.total ?? 0
+
+    const rows = db
+      .prepare(`SELECT rowid FROM message_fts WHERE content MATCH ? ORDER BY rank LIMIT ? OFFSET ?`)
+      .all(matchQuery, limit, offset) as Array<{ rowid: number }>
+
+    return {
+      rowids: rows.map((r) => r.rowid),
+      total,
+    }
+  } catch (error) {
+    console.error('[FTS] Search failed, query:', matchQuery, error)
+    return { rowids: [], total: 0 }
+  }
+}
diff --git a/packages/node-runtime/src/index.ts b/packages/node-runtime/src/index.ts
index 1577fea1..904bc761 100644
--- a/packages/node-runtime/src/index.ts
+++ b/packages/node-runtime/src/index.ts
@@ -11,6 +11,9 @@ export { BetterSqliteAdapter, openBetterSqliteDatabase } from './better-sqlite3-
 export { writeParseResultToDb } from './import'
 export type { ImportMeta, WriteParseResultStats } from './import'
 
+// FTS5 full-text search operations
+export { hasFtsTable, createFtsTable, buildFtsIndex, rebuildFtsIndex, insertFtsEntries, searchByFts } from './fts'
+
 // AI Logger
 export { AiLogger, extractErrorInfo, extractErrorStack } from './ai'
 export { NodePathProvider } from './node-path-provider'