diff --git a/README.md b/README.md
index 9d4873ec0..f4e0ad687 100644
--- a/README.md
+++ b/README.md
@@ -135,7 +135,7 @@ Fully modular pipeline from document parsing, vectorization, and retrieval to LL
 | Embeddings | Ollama / BGE / GTE / Zhipu / OpenAI-compatible APIs |
 | Vector DBs | PostgreSQL (pgvector) / Elasticsearch / OpenSearch / Milvus / Weaviate / Qdrant / Apache Doris / Tencent VectorDB |
 | Object Storage | Local / MinIO / AWS S3 / Volcengine TOS / Alibaba Cloud OSS / Kingsoft Cloud KS3 / Huawei Cloud OBS |
-| IM Channels | WeCom / Feishu / Slack / Telegram / DingTalk / Mattermost / WeChat |
+| IM Channels | WeCom / Feishu / Lark / Slack / Telegram / DingTalk / Mattermost / WeChat |
 | Website Embed | Publish agents via embed widget with domain allowlists, rate limits, and secure-mode token exchange |
 | Web Search | DuckDuckGo / Bing / Google / Tavily / Baidu / Ollama / SearXNG |
 
diff --git a/README_CN.md b/README_CN.md
index c49fc2b3e..a961b3557 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -134,7 +134,7 @@
 | 向量数据库 | PostgreSQL (pgvector) / Elasticsearch / OpenSearch / Milvus / Weaviate / Qdrant / Apache Doris / 腾讯云 VectorDB |
 | Embedding | Ollama / BGE / GTE / 智谱 / OpenAI 兼容接口 |
 | 对象存储 | 本地 / 腾讯云COS / 火山引擎 TOS / MinIO / AWS S3 / 阿里云 OSS / 金山云 KS3 / 华为云 OBS |
-| IM 集成 | 企业微信 / 飞书 / Slack / Telegram / 钉钉 / Mattermost / 微信 |
+| IM 集成 | 企业微信 / 飞书 / Lark / Slack / Telegram / 钉钉 / Mattermost / 微信 |
 | 网站嵌入 | 通过嵌入 Widget 发布智能体，支持域名白名单、限流与安全模式 Token 交换 |
 | 网络搜索 | DuckDuckGo / Bing / Google / Tavily / Baidu / Ollama / SearXNG |
 
diff --git a/README_JA.md b/README_JA.md
index f8ccfcd26..2aa2f06e5 100644
--- a/README_JA.md
+++ b/README_JA.md
@@ -135,7 +135,7 @@ Feishu、Notion、Yuqueなどの外部プラットフォームからのナレッ
 | Embedding | Ollama / BGE / GTE / OpenAI 互換 API |
 | ベクトル DB | PostgreSQL (pgvector) / Elasticsearch / OpenSearch / Milvus / Weaviate / Qdrant / Apache Doris / Tencent VectorDB |
 | オブジェクトストレージ | ローカル / MinIO / AWS S3 / 火山引擎 TOS / Alibaba Cloud OSS / 金山雲 KS3 |
-| IM 統合 | WeChat Work / Feishu / Slack / Telegram / DingTalk / Mattermost / WeChat |
+| IM 統合 | WeChat Work / Feishu / Lark / Slack / Telegram / DingTalk / Mattermost / WeChat |
 | ウェブ埋め込み | 埋め込み Widget でエージェントを公開、ドメイン許可リスト・レート制限・セキュアモード Token 交換 |
 | Web 検索 | DuckDuckGo / Bing / Google / Tavily / Baidu / Ollama / SearXNG |
 
diff --git a/README_KO.md b/README_KO.md
index d6e6490be..1a5410f19 100644
--- a/README_KO.md
+++ b/README_KO.md
@@ -144,7 +144,7 @@ Feishu, Notion, Yuque 등 외부 플랫폼에서 지식 자동 동기화를 지
 | Embedding | Ollama / BGE / GTE / OpenAI 호환 API |
 | 벡터 DB | PostgreSQL (pgvector) / Elasticsearch / OpenSearch / Milvus / Weaviate / Qdrant / Apache Doris / Tencent VectorDB |
 | 오브젝트 스토리지 | 로컬 / MinIO / AWS S3 / Volcengine TOS / Alibaba Cloud OSS / Kingsoft Cloud KS3 |
-| IM 통합 | WeChat Work / Feishu / Slack / Telegram / DingTalk / Mattermost / WeChat |
+| IM 통합 | WeChat Work / Feishu / Lark / Slack / Telegram / DingTalk / Mattermost / WeChat |
 | 웹사이트 임베드 | 임베드 Widget으로 에이전트 게시, 도메인 허용 목록·속도 제한·보안 모드 Token 교환 |
 | 웹 검색 | DuckDuckGo / Bing / Google / Tavily / Baidu / Ollama / SearXNG |
 
diff --git a/docs/IM集成开发文档.md b/docs/IM集成开发文档.md
index 117ae1c1f..7779c5266 100644
--- a/docs/IM集成开发文档.md
+++ b/docs/IM集成开发文档.md
@@ -1,6 +1,6 @@
 # IM 集成开发文档
 
-WeKnora 的 IM 集成模块将企业即时通讯平台（企业微信、飞书、Slack、Telegram、钉钉、Mattermost）接入 WeKnora 知识问答管道，支持在 IM 中直接向 AI 提问并获得实时流式回答。
+WeKnora 的 IM 集成模块将企业即时通讯平台（企业微信、飞书、Lark、Slack、Telegram、钉钉、Mattermost）接入 WeKnora 知识问答管道，支持在 IM 中直接向 AI 提问并获得实时流式回答。
 
 IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道，所有配置通过前端 Agent 编辑器管理，存储在数据库中。
 
@@ -9,6 +9,7 @@ IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道，所有配置
 - [快速接入指南](#快速接入指南)
   - [企业微信接入](#企业微信接入)
   - [飞书接入](#飞书接入)
+  - [Lark 接入](#lark-接入)
   - [Slack 接入](#slack-接入)
   - [Telegram 接入](#telegram-接入)
   - [钉钉接入](#钉钉接入)
@@ -22,7 +23,7 @@ IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道，所有配置
 - [接口定义](#接口定义)
 - [平台适配器详解](#平台适配器详解)
   - [企业微信 (WeCom)](#企业微信-wecom)
-  - [飞书 (Feishu)](#飞书-feishu)
+  - [飞书 (Feishu) 与 Lark](#飞书-feishu-与-lark)
   - [Slack](#slack)
   - [Telegram](#telegram)
   - [钉钉 (DingTalk)](#钉钉-dingtalk)
@@ -234,6 +235,64 @@ IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道，所有配置
 
 ---
 
+### Lark 接入
+
+Lark 是飞书的国际版。两者是同一产品部署在两朵相互隔离的云上，**IM 的 API 接口、事件结构、
+凭证字段、接入模式一致**，因此 WeKnora 中 Lark 与飞书共用同一套适配器代码。
+
+但「代码一致」不等于「配置一致」，接入时有三处差别：
+
+| | 飞书 | Lark |
+|---|---|---|
+| 开放平台 | <https://open.feishu.cn/> | <https://open.larksuite.com/> |
+| 添加渠道时的**平台**选项 | 「飞书」 | 「Lark（飞书国际版）」 |
+| 权限清单 | [飞书接入](#飞书接入)一节的 JSON | [Lark 权限配置](#lark-权限配置)一节的 JSON（**不可套用飞书的**） |
+
+创建应用、添加机器人能力、订阅 `im.message.receive_v1` 事件、发布版本、填写
+App ID / App Secret 等步骤与[飞书接入](#飞书接入)一节相同。**唯独权限配置不同，见下。**
+
+#### Lark 权限配置
+
+在 Lark 开放平台 **权限管理 → 批量导入** 粘贴下面的 JSON，覆盖 IM 机器人与知识库（Wiki）
+数据源两块功能：
+
+```json
+{
+  "scopes": {
+    "tenant": [
+      "im:message",
+      "im:message:send_as_bot",
+      "im:resource",
+      "im:message.p2p_msg:readonly",
+      "im:message.group_at_msg:readonly",
+      "cardkit:card:write",
+      "wiki:wiki:readonly",
+      "drive:export:readonly",
+      "drive:drive:readonly",
+      "docx:document:readonly"
+    ],
+    "user": []
+  }
+}
+```
+
+> 不要套用[飞书接入](#飞书接入)一节的 JSON：其中 `aily:file:*`、`corehr:file:download`
+> 在 Lark 不存在，整份导入会失败。
+
+> **注意**：飞书应用与 Lark 应用互不通用。在 open.feishu.cn 创建的应用无法用于 Lark 渠道，
+> 反之亦然——凭证只在创建它的那朵云上有效，跨云调用会认证失败。
+
+WebSocket 模式启动后日志出现以下内容表示连接成功：
+
+```
+[IM] Lark WebSocket connecting (app_id=xxx)...
+```
+
+同一个 App ID 在两朵云上分别注册时，WeKnora 通过 `平台:app_id` 区分（如 `feishu:cli_xxx`
+与 `lark:cli_xxx`），两个渠道可以并存，会话互不干扰。
+
+---
+
 ### Slack 接入
 
 Slack 提供两种接入模式，推荐使用 WebSocket (Socket Mode) 模式，无需公网域名。
@@ -520,7 +579,7 @@ IM 渠道在 Agent 编辑器的 **IM 集成** 标签页中管理（仅编辑模
 ### 渠道列表
 
 每个渠道以卡片形式展示，包含：
-- **平台标识**：企业微信（绿色）/ 飞书（蓝色）/ Slack（紫色）/ Telegram（蓝色）/ 钉钉（蓝色）/ Mattermost（蓝色）
+- **平台标识**：企业微信（绿色）/ 飞书（青色）/ Lark（蓝色）/ Slack（紫色）/ Telegram（蓝色）/ 钉钉（蓝色）/ Mattermost（蓝色）
 - **渠道名称**：用户自定义
 - **接入模式**：WebSocket / Webhook
 - **输出模式**：流式输出 / 完整输出
@@ -615,7 +674,7 @@ CREATE TABLE im_channels (
     id                VARCHAR(36) PRIMARY KEY,
     tenant_id         BIGINT NOT NULL,
     agent_id          VARCHAR(36) NOT NULL,       -- 绑定的 Agent ID
-    platform          VARCHAR(20) NOT NULL,       -- 'wecom' | 'feishu' | 'slack' | 'telegram' | 'dingtalk' | 'mattermost'
+    platform          VARCHAR(20) NOT NULL,       -- 'wecom' | 'feishu' | 'lark' | 'slack' | 'telegram' | 'dingtalk' | 'mattermost'
     name              VARCHAR(255) NOT NULL DEFAULT '',
     enabled           BOOLEAN NOT NULL DEFAULT true,
     mode              VARCHAR(20) NOT NULL DEFAULT 'websocket',  -- 'webhook' | 'websocket'
@@ -635,8 +694,8 @@ CREATE TABLE im_channels (
 |------|------|------|
 | 企业微信 | WebSocket | `bot_id`, `bot_secret` |
 | 企业微信 | Webhook | `corp_id`, `agent_secret`, `token`, `encoding_aes_key`, `corp_agent_id` |
-| 飞书 | WebSocket | `app_id`, `app_secret` |
-| 飞书 | Webhook | `app_id`, `app_secret`, `verification_token`, `encrypt_key` |
+| 飞书 / Lark | WebSocket | `app_id`, `app_secret` |
+| 飞书 / Lark | Webhook | `app_id`, `app_secret`, `verification_token`, `encrypt_key` |
 | Slack | WebSocket | `app_token`, `bot_token` |
 | Slack | Webhook | `bot_token`, `signing_secret` |
 | Telegram | WebSocket | `bot_token` |
@@ -697,7 +756,7 @@ CREATE TABLE im_channels (
 
 ```go
 type IncomingMessage struct {
-    Platform    Platform          // "wecom" | "feishu" | "slack" | "telegram" | "dingtalk" | "mattermost"
+    Platform    Platform          // "wecom" | "feishu" | "lark" | "slack" | "telegram" | "dingtalk" | "mattermost"
     MessageType MessageType       // "text" | "file" | "image"
     UserID      string            // 平台用户标识
     UserName    string            // 显示名 (可选)
@@ -921,10 +980,71 @@ LongConnClient ══WebSocket══▶ wss://openws.work.weixin.qq.com
 
 ---
 
-### 飞书 (Feishu)
+### 飞书 (Feishu) 与 Lark
 
 统一适配器同时支持 Webhook 和 WebSocket 模式，且原生实现 `StreamSender` 和 `FileDownloader` 接口。
 
+#### 双云共用一套适配器
+
+飞书与 Lark 是同一产品部署在两朵隔离的云上，API 与事件结构完全一致，因此 `internal/im/feishu`
+包同时服务两个平台，由 `Region` 决定具体连哪朵云：
+
+```go
+// internal/im/feishu/region.go
+type Region struct {
+    Platform           im.Platform  // "feishu" | "lark"，写入 IncomingMessage
+    OpenBaseURL        string       // https://open.feishu.cn | https://open.larksuite.com
+    Label              string       // 日志前缀 [Feishu] / [Lark]
+    ThinkingText       string       // 流式卡片占位文案（中文 / 英文）
+    ImageFallbackLabel string       // 图片上传失败时降级链接的文案
+}
+
+var (
+    RegionFeishu = Region{Platform: im.PlatformFeishu, OpenBaseURL: "https://open.feishu.cn", ...}
+    RegionLark   = Region{Platform: im.PlatformLark,   OpenBaseURL: "https://open.larksuite.com", ...}
+)
+```
+
+容器中注册为两个平台：
+
+```go
+// internal/container/container.go
+imService.RegisterAdapterFactory("feishu", feishu.NewFactory(feishu.RegionFeishu))
+imService.RegisterAdapterFactory("lark", feishu.NewFactory(feishu.RegionLark))
+```
+
+适配器所有 API 调用经 `a.api(path, args...)` 拼接 `region.OpenBaseURL`；WebSocket 模式通过
+`larkws.WithDomain(region.OpenBaseURL)` 指向对应云（SDK 默认连 open.feishu.cn，Lark 不指定会认证失败）。
+
+> **跨云资源不通用**：`tenant_access_token`、`image_key`、`file_key`、`card_id` 均由单朵云的
+> 单个应用签发，跨云或跨应用使用会被拒绝。图片上传缓存因此以 `app_id` 为前缀分区。
+
+#### IM 适配器实际调用的接口与所需权限
+
+下表说明适配器**实际**依赖哪些权限。表中的权限标识已对照 Lark 官方 API 文档逐条核对，
+飞书侧同名。
+
+> **两朵云的权限清单并不等价。** API 与事件结构一致，不代表权限目录一致——飞书开放平台
+> 上存在的部分权限，Lark 开放平台并没有。因此各自的配置清单请分别参照
+> [飞书接入](#飞书接入)与 [Lark 权限配置](#lark-权限配置)，不要跨云复制粘贴。
+>
+> 飞书一节的 JSON 还同时覆盖了**飞书数据源连接器**（Wiki 同步），所以包含
+> `wiki:wiki:readonly`、`docs:document.content:read`、`sheets:spreadsheet` 等 IM 用不到的权限。
+
+| 适配器调用 | 用途 | 所需权限（满足其一即可） |
+|---|---|---|
+| `POST /auth/v3/tenant_access_token/internal` | 换取 tenant access token | 无需权限（凭 App ID / Secret） |
+| `POST /im/v1/messages/{id}/reply` | 回复消息（主路径） | `im:message`、`im:message:send_as_bot` 或 `im:message:send` |
+| `POST /im/v1/messages` | 发送消息（回复失败时降级） | 同上 |
+| `GET /im/v1/messages/{id}/resources/{key}` | 下载用户发来的文件 / 图片 | `im:message` 或 `im:message:readonly` |
+| `POST /im/v1/images` | 上传图片以取得 `image_key` | `im:resource` 或 `im:resource:upload` |
+| `POST /cardkit/v1/cards`<br>`PUT /cardkit/v1/cards/{id}/elements/{eid}/content`<br>`PATCH /cardkit/v1/cards/{id}/settings` | 流式卡片（仅流式输出模式需要） | `cardkit:card:write` |
+| 订阅事件 `im.message.receive_v1`（单聊） | 接收私聊消息 | `im:message.p2p_msg` 或 `im:message.p2p_msg:readonly` |
+| 订阅事件 `im.message.receive_v1`（群聊 @） | 接收群内 @机器人 消息 | `im:message.group_at_msg` 或 `im:message.group_at_msg:readonly` |
+
+因此 IM 功能全开（私聊 + 群聊 @ + 文件 + 图片 + 流式卡片）最少需要 5 类权限：收私聊、收群 @、
+发消息、读写资源、写卡片。若关闭流式输出（输出模式选「完整输出」），`cardkit:card:write` 可省略。
+
 #### Webhook 模式
 
 ```
@@ -974,14 +1094,21 @@ EndStream:
 > [thinking content line 2]
 ```
 
+> **已知限制**：`Region.ThinkingText` 只本地化了卡片的初始占位文案（Lark 显示 `Thinking...`）。
+> 一旦开始流式输出，think 块标题来自共享的 `MarkdownThinkStyle`，目前对所有平台
+> （Lark、Slack、Telegram、Mattermost 等）都是中文。本地化它需要把 locale 贯穿到
+> `FormatIMDisplayContent`，属于跨平台改动，不在 Lark 接入范围内。
+
 **孤立流清理：** 后台协程每 1 分钟扫描超过 5 分钟未关闭的流式卡片，自动调用 `EndStream` 关闭（防止内存泄漏）。
 
 #### 源码文件
 
 | 文件 | 职责 |
 |------|------|
+| `internal/im/feishu/region.go` | `Region` 定义（飞书 / Lark 的域名、平台标识、日志前缀、本地化文案） |
 | `internal/im/feishu/adapter.go` | 事件解析、CardKit 流式实现、Token 缓存、AES 解密、Think 块转换、文件下载 |
 | `internal/im/feishu/longconn.go` | WebSocket 长连接（封装飞书 SDK）、事件分发 |
+| `internal/im/feishu/factory.go` | 按 `Region` 构造适配器与长连接客户端 |
 
 ---
 
diff --git a/docs/wiki/集成扩展/IM集成开发.md b/docs/wiki/集成扩展/IM集成开发.md
index 3c93fe7b0..4510c34c0 100644
--- a/docs/wiki/集成扩展/IM集成开发.md
+++ b/docs/wiki/集成扩展/IM集成开发.md
@@ -1,13 +1,13 @@
 ---
 title: IM集成开发
-tags: [集成扩展, IM, 企微, 飞书, Slack, Telegram, 钉钉, Mattermost]
+tags: [集成扩展, IM, 企微, 飞书, Lark, Slack, Telegram, 钉钉, Mattermost]
 aliases: [IM集成, IM开发, 企业微信, 即时通讯]
 source: IM集成开发文档.md
 ---
 
 # IM 集成开发
 
-WeKnora 的 IM 集成模块将企业即时通讯平台（企业微信、飞书、Slack、Telegram、钉钉、Mattermost）接入 WeKnora 知识问答管道，支持在 IM 中直接向 AI 提问并获得实时流式回答。
+WeKnora 的 IM 集成模块将企业即时通讯平台（企业微信、飞书、Lark、Slack、Telegram、钉钉、Mattermost）接入 WeKnora 知识问答管道，支持在 IM 中直接向 AI 提问并获得实时流式回答。
 
 IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道。
 
@@ -19,6 +19,7 @@ IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道。
 |------|:-:|:-:|:-:|
 | 企业微信 | ✅ | ✅ | ✅ |
 | 飞书 | ✅ | ✅ | ✅ (CardKit) |
+| Lark（飞书国际版） | ✅ | ✅ | ✅ (CardKit) |
 | Slack | ✅ (Socket Mode) | ✅ (Events API) | ✅ |
 | Telegram | ✅ (长轮询) | ✅ | ✅ |
 | 钉钉 | ✅ (Stream) | ✅ | ✅ (AI 卡片) |
@@ -47,6 +48,20 @@ IM 渠道绑定到 Agent，一个 Agent 可接入多个 IM 渠道。
 
 > 飞书同时也是数据源导入的支持平台，参见 [数据源导入开发](数据源导入开发.md)
 
+### Lark 接入
+
+Lark 是飞书的国际版，IM 接口一致，与飞书共用同一套适配器。接入步骤基本相同，但开放平台
+与**权限清单**不同：
+
+- 飞书：<https://open.feishu.cn/>
+- Lark：<https://open.larksuite.com/>
+
+> **权限不可套用飞书的清单**：飞书清单混入了数据源连接器（Wiki 同步）用的权限，其中部分在
+> Lark 并不存在，整份导入会失败。Lark 只需 IM 相关的 6 项，见
+> [IM集成开发文档 — Lark 权限配置](../../IM集成开发文档.md#lark-权限配置)。
+
+> 两朵云的应用互不通用，凭证只在创建它的那朵云上有效。
+
 ### Slack 接入
 
 - **Socket Mode**（推荐）— 无需公网域名
diff --git a/docs/数据源导入开发文档.md b/docs/数据源导入开发文档.md
index a5255c315..172aaaeb4 100644
--- a/docs/数据源导入开发文档.md
+++ b/docs/数据源导入开发文档.md
@@ -82,7 +82,42 @@ WeKnora 的数据源导入模块支持从外部平台（飞书、企业微信、
 - **成功**：显示已创建/更新/跳过/失败的文档数量
 - **失败**：显示错误信息，常见原因为权限不足或 Token 过期
 
-> **注意**：飞书国际版（Lark）同样支持，在创建数据源时会自动适配 `https://open.larksuite.com` 的 API 地址。
+---
+
+### Lark 知识库接入
+
+Lark 是飞书的国际版。Wiki / docx / drive 接口与飞书一致，**共用同一套连接器代码**，接入步骤
+与[飞书知识库接入](#飞书知识库接入)相同，差别只有三处：
+
+| | 飞书 | Lark |
+|---|---|---|
+| 开放平台 | <https://open.feishu.cn/> | <https://open.larksuite.com/> |
+| 连接器类型 | 「飞书」 | 「Lark」 |
+| API 地址 | `https://open.feishu.cn` | `https://open.larksuite.com`（选中 Lark 类型后自动使用） |
+
+#### Lark 权限
+
+权限标识与飞书相同，在 Lark 开放平台的 **权限管理** 中开通：
+
+| 权限 | 说明 | Lark 官方文档核对 |
+|------|------|------|
+| `wiki:wiki:readonly` | 读取知识库空间列表和节点树 | ✅ 已核对 |
+| `drive:export:readonly` | 导出文档内容（docx/xlsx） | ✅ 已核对 |
+| `drive:drive:readonly` | 读取云文档基础信息、下载文件 | ✅ 已核对 |
+| `docx:document:readonly` | 读取新版文档内容 | ⚠️ 未能核对（Lark 文档页渲染受限），沿用飞书侧标识 |
+
+> **不要套用 [IM 集成文档](./IM集成开发文档.md#飞书接入)里的那份权限 JSON**：那份清单混入了
+> `aily:file:*`、`corehr:file:download` 等在 Lark 并不存在的权限（整份导入会失败），
+> 且反而**缺少**上表中数据源真正需要的 `drive:*` / `docx:*`。
+>
+> 若同一个 Lark 应用既做 IM 机器人又做知识库同步，请使用
+> [IM 集成文档 — Lark 权限配置](./IM集成开发文档.md#lark-权限配置)中的合并清单。
+
+#### 应用互不通用
+
+在 open.feishu.cn 创建的应用无法读取 Lark 知识库，反之亦然——凭证只在创建它的那朵云上有效。
+若你此前用「飞书」连接器加 `base_url=https://open.larksuite.com` 的方式接入过 Lark，该配置
+仍然有效（`base_url` 保留为显式覆盖项），但新建数据源请直接选「Lark」类型。
 
 ---
 
diff --git a/frontend/src/api/agent/index.ts b/frontend/src/api/agent/index.ts
index 3863ebf1e..d02a21991 100644
--- a/frontend/src/api/agent/index.ts
+++ b/frontend/src/api/agent/index.ts
@@ -295,7 +295,8 @@ export interface IMChannel {
   id: string;
   tenant_id?: number;
   agent_id: string;
-  platform: 'wecom' | 'feishu' | 'slack' | 'telegram' | 'dingtalk' | 'mattermost' | 'wechat' | 'qqbot';
+  // 'lark' is Feishu's international edition; it shares Feishu's credentials and modes.
+  platform: 'wecom' | 'feishu' | 'lark' | 'slack' | 'telegram' | 'dingtalk' | 'mattermost' | 'wechat' | 'qqbot';
   name: string;
   enabled: boolean;
   mode: 'webhook' | 'websocket' | 'longpoll';
diff --git a/frontend/src/assets/img/datasource-lark.svg b/frontend/src/assets/img/datasource-lark.svg
new file mode 100644
index 000000000..b3e710cf0
--- /dev/null
+++ b/frontend/src/assets/img/datasource-lark.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="1em" height="1em" viewBox="0 0 48 48"><g fill="#3370ff" fill-rule="evenodd" clip-rule="evenodd"><path d="M41.0716 5.99409L3.31071 16.5187L12.3856 25.8126L20.7998 25.9594L30.4827 16.5187C30.2266 15.9943 30.0985 15.5552 30.0985 15.2013C30.0985 14.4074 30.4104 13.7786 30.8947 13.333C31.7241 12.57 32.7222 12.4558 33.8889 12.9905L41.0716 5.99409Z"/><path d="M42.1021 6.72842L31.5775 44.4893L22.2836 35.4144L22.1367 27.0002L31.5115 17.4816C32.0195 17.8454 32.5743 18.0105 33.1759 17.9769C34.0784 17.9264 34.6614 17.3813 34.9349 17.0602C35.2083 16.7392 35.5293 16.2051 35.5025 15.4113C35.4847 14.8821 35.3109 14.3941 34.9812 13.9472L42.1021 6.72842Z"/></g></svg>
diff --git a/frontend/src/assets/img/im/lark.svg b/frontend/src/assets/img/im/lark.svg
new file mode 100644
index 000000000..b3e710cf0
--- /dev/null
+++ b/frontend/src/assets/img/im/lark.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="1em" height="1em" viewBox="0 0 48 48"><g fill="#3370ff" fill-rule="evenodd" clip-rule="evenodd"><path d="M41.0716 5.99409L3.31071 16.5187L12.3856 25.8126L20.7998 25.9594L30.4827 16.5187C30.2266 15.9943 30.0985 15.5552 30.0985 15.2013C30.0985 14.4074 30.4104 13.7786 30.8947 13.333C31.7241 12.57 32.7222 12.4558 33.8889 12.9905L41.0716 5.99409Z"/><path d="M42.1021 6.72842L31.5775 44.4893L22.2836 35.4144L22.1367 27.0002L31.5115 17.4816C32.0195 17.8454 32.5743 18.0105 33.1759 17.9769C34.0784 17.9264 34.6614 17.3813 34.9349 17.0602C35.2083 16.7392 35.5293 16.2051 35.5025 15.4113C35.4847 14.8821 35.3109 14.3941 34.9812 13.9472L42.1021 6.72842Z"/></g></svg>
diff --git a/frontend/src/components/IMChannelPanel.vue b/frontend/src/components/IMChannelPanel.vue
index 9600220bc..f27a9751b 100644
--- a/frontend/src/components/IMChannelPanel.vue
+++ b/frontend/src/components/IMChannelPanel.vue
@@ -295,11 +295,11 @@
               </template>
             </template>
 
-            <!-- Feishu credentials -->
-            <template v-if="formData.platform === 'feishu'">
+            <!-- Feishu / Lark credentials — same fields, different open platform -->
+            <template v-if="formData.platform === 'feishu' || formData.platform === 'lark'">
               <div class="platform-link-hint">
-                <a href="https://open.feishu.cn/" target="_blank" rel="noopener noreferrer" class="doc-link">
-                  {{ $t('agentEditor.im.feishuConsole') }}
+                <a :href="openPlatformConsole.url" target="_blank" rel="noopener noreferrer" class="doc-link">
+                  {{ $t(openPlatformConsole.labelKey) }}
                   <t-icon name="link" class="link-icon" />
                 </a>
                 <span class="hint-text">{{ $t('agentEditor.im.consoleTip') }}</span>
@@ -538,6 +538,7 @@ import SettingDrawer from '@/components/settings/SettingDrawer.vue';
 import IntegrationsAgentFilter from '@/components/IntegrationsAgentFilter.vue';
 import wecomLogo from '@/assets/img/im/wecom.svg';
 import feishuLogo from '@/assets/img/im/feishu.svg';
+import larkLogo from '@/assets/img/im/lark.svg';
 import slackLogo from '@/assets/img/im/slack.svg';
 import telegramLogo from '@/assets/img/im/telegram.svg';
 import dingtalkLogo from '@/assets/img/im/dingtalk.svg';
@@ -550,6 +551,7 @@ type IMPlatform = IMChannel['platform'];
 const PLATFORM_LOGO: Record<string, string> = {
   wecom: wecomLogo,
   feishu: feishuLogo,
+  lark: larkLogo,
   slack: slackLogo,
   telegram: telegramLogo,
   dingtalk: dingtalkLogo,
@@ -600,6 +602,7 @@ const drawerConfirmText = computed(() =>
 const platformOptions = computed(() => ([
   { value: 'wecom' as IMPlatform, label: t('agentEditor.im.wecom'), logo: wecomLogo },
   { value: 'feishu' as IMPlatform, label: t('agentEditor.im.feishu'), logo: feishuLogo },
+  { value: 'lark' as IMPlatform, label: t('agentEditor.im.lark'), logo: larkLogo },
   { value: 'slack' as IMPlatform, label: t('agentEditor.im.slack'), logo: slackLogo },
   { value: 'telegram' as IMPlatform, label: t('agentEditor.im.telegram'), logo: telegramLogo },
   { value: 'dingtalk' as IMPlatform, label: t('agentEditor.im.dingtalk'), logo: dingtalkLogo },
@@ -608,6 +611,14 @@ const platformOptions = computed(() => ([
   { value: 'qqbot' as IMPlatform, label: t('agentEditor.im.qqbot'), logo: qqbotLogo },
 ]));
 
+// Feishu and Lark are the same product on separate clouds, so each has its own
+// open platform console. Bots must be created on the one matching the channel.
+const openPlatformConsole = computed(() =>
+  formData.value.platform === 'lark'
+    ? { url: 'https://open.larksuite.com/', labelKey: 'agentEditor.im.larkConsole' }
+    : { url: 'https://open.feishu.cn/', labelKey: 'agentEditor.im.feishuConsole' },
+);
+
 const drawerTitle = computed(() => {
   if (editingChannel.value) {
     return formData.value.name?.trim() || t('agentEditor.im.unnamed');
@@ -708,7 +719,7 @@ function resolvedChannelName(): string {
 }
 
 function platformSupportsThread(platform: string): boolean {
-  return ['slack', 'mattermost', 'feishu', 'telegram'].includes(platform);
+  return ['slack', 'mattermost', 'feishu', 'lark', 'telegram'].includes(platform);
 }
 
 watch(
diff --git a/frontend/src/components/menu.vue b/frontend/src/components/menu.vue
index 8b39834f4..3b2d24151 100644
--- a/frontend/src/components/menu.vue
+++ b/frontend/src/components/menu.vue
@@ -255,6 +255,7 @@ const chatResources = useChatResourcesStore();
 // visually consistent with the channels admin view.
 import wecomLogo from '@/assets/img/im/wecom.svg';
 import feishuLogo from '@/assets/img/im/feishu.svg';
+import larkLogo from '@/assets/img/im/lark.svg';
 import slackLogo from '@/assets/img/im/slack.svg';
 import telegramLogo from '@/assets/img/im/telegram.svg';
 import dingtalkLogo from '@/assets/img/im/dingtalk.svg';
@@ -265,6 +266,7 @@ import qqbotLogo from '@/assets/img/im/qqbot.png';
 const PLATFORM_LOGO: Record<string, string> = {
     wecom: wecomLogo,
     feishu: feishuLogo,
+    lark: larkLogo,
     slack: slackLogo,
     telegram: telegramLogo,
     dingtalk: dingtalkLogo,
diff --git a/frontend/src/i18n/locales/en-US.ts b/frontend/src/i18n/locales/en-US.ts
index 6cc33a1e3..10d048c49 100755
--- a/frontend/src/i18n/locales/en-US.ts
+++ b/frontend/src/i18n/locales/en-US.ts
@@ -5840,8 +5840,9 @@ export default {
     },
     im: {
       title: 'IM Integration',
-      description: 'Connect agent to instant messaging platforms like WeCom, Feishu, Slack, Telegram, DingTalk, Mattermost, WeChat and QQBot',
+      description: 'Connect agent to instant messaging platforms like WeCom, Feishu, Lark, Slack, Telegram, DingTalk, Mattermost, WeChat and QQBot',
       feishu: 'Feishu',
+      lark: 'Lark',
       slack: 'Slack',
       telegram: 'Telegram',
       dingtalk: 'DingTalk',
@@ -5868,6 +5869,7 @@ export default {
       docLink: 'Integration Guide',
       wecomConsole: 'WeCom Admin Console',
       feishuConsole: 'Feishu Open Platform',
+      larkConsole: 'Lark Open Platform',
       slackConsole: 'Slack API Console',
       telegramConsole: 'Telegram BotFather',
       dingtalkConsole: 'DingTalk Open Platform',
@@ -6162,12 +6164,14 @@ export default {
     },
     connector: {
       feishu: 'Feishu',
+      lark: 'Lark',
       notion: 'Notion',
       yuque: 'Yuque',
       rss: 'RSS / Atom Feed',
     },
     connectorDesc: {
       feishu: 'Sync documents, spreadsheets and files from Feishu Wiki',
+      lark: 'Sync documents, spreadsheets and files from Lark Wiki (Feishu international)',
       notion: 'Sync pages and databases from Notion',
       yuque: 'Sync documents from Yuque knowledge bases',
       rss: 'Sync articles from RSS / Atom feeds',
diff --git a/frontend/src/i18n/locales/ko-KR.ts b/frontend/src/i18n/locales/ko-KR.ts
index 9a0666a43..35652f460 100755
--- a/frontend/src/i18n/locales/ko-KR.ts
+++ b/frontend/src/i18n/locales/ko-KR.ts
@@ -5777,6 +5777,7 @@ export default {
       description: "에이전트를 Feishu, Slack, Telegram, DingTalk, Mattermost, QQBot 등 인스턴트 메시징 플랫폼에 연결",
       wecom: "WeCom",
       feishu: "Feishu",
+      lark: "Lark",
       slack: "Slack",
       telegram: "Telegram",
       dingtalk: "DingTalk",
@@ -5802,6 +5803,7 @@ export default {
       docLink: "통합 가이드 보기",
       wecomConsole: "WeCom 관리 콘솔",
       feishuConsole: "Feishu 개발 플랫폼",
+      larkConsole: "Lark 개발 플랫폼",
       slackConsole: "Slack API 콘솔",
       telegramConsole: "Telegram BotFather",
       dingtalkConsole: "DingTalk 개발 플랫폼",
@@ -6167,12 +6169,14 @@ export default {
     },
     connector: {
       feishu: "페이슈 (Feishu)",
+      lark: "Lark (Feishu 글로벌)",
       notion: "Notion",
       yuque: "위큐 (Yuque)",
       rss: "RSS / Atom 피드",
     },
     connectorDesc: {
       feishu: "페이슈 위키에서 문서, 스프레드시트, 파일 동기화",
+      lark: "Lark 위키에서 문서, 스프레드시트, 파일 동기화",
       notion: "Notion에서 페이지 및 데이터베이스 동기화",
       yuque: "위큐 지식베이스에서 문서 동기화",
       rss: "RSS / Atom 피드에서 글 동기화",
diff --git a/frontend/src/i18n/locales/ru-RU.ts b/frontend/src/i18n/locales/ru-RU.ts
index b0230098e..9146d178e 100755
--- a/frontend/src/i18n/locales/ru-RU.ts
+++ b/frontend/src/i18n/locales/ru-RU.ts
@@ -5347,6 +5347,7 @@ export default {
       description: 'Подключите агента к платформам мгновенных сообщений, таким как Feishu, Slack, Telegram, DingTalk, Mattermost и QQBot',
       wecom: 'WeCom',
       feishu: 'Feishu',
+      lark: 'Lark',
       slack: 'Slack',
       telegram: 'Telegram',
       dingtalk: 'DingTalk',
@@ -5372,6 +5373,7 @@ export default {
       docLink: 'Руководство по интеграции',
       wecomConsole: 'Консоль WeCom',
       feishuConsole: 'Платформа Feishu',
+      larkConsole: 'Платформа Lark',
       slackConsole: 'Консоль Slack API',
       telegramConsole: 'Telegram BotFather',
       dingtalkConsole: 'Платформа DingTalk',
@@ -5988,12 +5990,14 @@ export default {
     },
     connector: {
       feishu: 'Feishu (Фэйшу)',
+      lark: 'Lark',
       notion: 'Notion',
       yuque: 'Yuque (Юйцюэ)',
       rss: 'RSS / Atom лента',
     },
     connectorDesc: {
       feishu: 'Синхронизация документов, таблиц и файлов из Feishu Wiki',
+      lark: 'Синхронизация документов, таблиц и файлов из Lark Wiki',
       notion: 'Синхронизация страниц и баз данных из Notion',
       yuque: 'Синхронизация документов из баз знаний Yuque',
       rss: 'Синхронизация статей из лент RSS / Atom',
diff --git a/frontend/src/i18n/locales/zh-CN.ts b/frontend/src/i18n/locales/zh-CN.ts
index 93b5f5eac..1da18fb55 100755
--- a/frontend/src/i18n/locales/zh-CN.ts
+++ b/frontend/src/i18n/locales/zh-CN.ts
@@ -5798,6 +5798,7 @@ export default {
       description: "将智能体接入即时通讯平台，支持企业微信、飞书、Slack、Telegram、钉钉、Mattermost、微信和 QQBot",
       wecom: "企业微信",
       feishu: "飞书",
+      lark: "Lark（飞书国际版）",
       slack: "Slack",
       telegram: "Telegram",
       dingtalk: "钉钉",
@@ -5823,6 +5824,7 @@ export default {
       docLink: "查看接入文档",
       wecomConsole: "企业微信管理后台",
       feishuConsole: "飞书开放平台",
+      larkConsole: "Lark 开放平台",
       slackConsole: "Slack API 控制台",
       telegramConsole: "Telegram BotFather",
       dingtalkConsole: "钉钉开放平台",
@@ -6187,12 +6189,14 @@ export default {
     },
     connector: {
       feishu: "飞书",
+      lark: "Lark（飞书国际版）",
       notion: "Notion",
       yuque: "语雀",
       rss: "RSS / Atom 订阅",
     },
     connectorDesc: {
       feishu: "同步飞书知识库中的文档、表格、文件",
+      lark: "同步 Lark 知识库中的文档、表格、文件（飞书国际版）",
       notion: "同步 Notion 中的页面和数据库",
       yuque: "同步语雀知识库中的文档",
       rss: "同步 RSS / Atom 订阅源中的文章",
diff --git a/frontend/src/views/knowledge/settings/DataSourceEditorDialog.vue b/frontend/src/views/knowledge/settings/DataSourceEditorDialog.vue
index ceffb6547..be0cd7cf3 100644
--- a/frontend/src/views/knowledge/settings/DataSourceEditorDialog.vue
+++ b/frontend/src/views/knowledge/settings/DataSourceEditorDialog.vue
@@ -368,6 +368,26 @@ const connectorDefs = computed<ConnectorDef[]>(() => [
       { key: 'app_secret', labelKey: 'datasource.field.appSecret', placeholder: '', secret: true },
     ],
   },
+  {
+    // Lark is Feishu's international cloud. Same wiki/docx/drive APIs and the
+    // same scope identifiers, but a separate console, tenant and app — an app
+    // created on open.feishu.cn cannot read a Lark wiki.
+    type: 'lark',
+    available: true,
+    docUrl: 'https://open.larksuite.com/app',
+    permissionDocUrl: 'https://open.larksuite.com/document/server-docs/docs/wiki-v2/wiki-overview',
+    permissionPageUrl: 'https://open.larksuite.com/app',
+    requiredPermissions: [
+      'wiki:wiki:readonly',
+      'drive:drive:readonly',
+      'drive:export:readonly',
+      'docx:document:readonly',
+    ],
+    fields: [
+      { key: 'app_id', labelKey: 'datasource.field.appId', placeholder: 'cli_xxxx' },
+      { key: 'app_secret', labelKey: 'datasource.field.appSecret', placeholder: '', secret: true },
+    ],
+  },
   {
     type: 'notion',
     available: true,
diff --git a/frontend/src/views/knowledge/settings/DataSourceTypeIcon.vue b/frontend/src/views/knowledge/settings/DataSourceTypeIcon.vue
index 0a18c175a..163c38ea1 100644
--- a/frontend/src/views/knowledge/settings/DataSourceTypeIcon.vue
+++ b/frontend/src/views/knowledge/settings/DataSourceTypeIcon.vue
@@ -17,6 +17,8 @@ function fallbackText(type: string) {
   switch (type) {
     case 'feishu':
       return 'F'
+    case 'lark':
+      return 'L'
     case 'notion':
       return 'N'
     case 'yuque':
diff --git a/frontend/src/views/knowledge/settings/datasourceIcons.ts b/frontend/src/views/knowledge/settings/datasourceIcons.ts
index e45b4e2c3..78e1c2541 100644
--- a/frontend/src/views/knowledge/settings/datasourceIcons.ts
+++ b/frontend/src/views/knowledge/settings/datasourceIcons.ts
@@ -1,10 +1,12 @@
 import feishuIcon from '@/assets/img/datasource-feishu.ico'
+import larkIcon from '@/assets/img/datasource-lark.svg'
 import notionIcon from '@/assets/img/datasource-notion.ico'
 import yuqueIcon from '@/assets/img/datasource-yuque.ico'
 import rssIcon from '@/assets/img/datasource-rss.svg'
 
 export const datasourceIconMap: Record<string, string> = {
   feishu: feishuIcon,
+  lark: larkIcon,
   notion: notionIcon,
   yuque: yuqueIcon,
   rss: rssIcon,
diff --git a/internal/container/container.go b/internal/container/container.go
index 52e099209..fff8c17c6 100644
--- a/internal/container/container.go
+++ b/internal/container/container.go
@@ -1550,7 +1550,9 @@ func registerWebSearchProviders(registry *infra_web_search.Registry) {
 // in its own subpackage to keep this file focused on wiring.
 func registerIMAdapterFactories(imService *imPkg.Service) {
 	imService.RegisterAdapterFactory("wecom", wecom.NewFactory())
-	imService.RegisterAdapterFactory("feishu", feishu.NewFactory())
+	imService.RegisterAdapterFactory("feishu", feishu.NewFactory(feishu.RegionFeishu))
+	// Lark is Feishu's international cloud: same adapter, different host/tenant.
+	imService.RegisterAdapterFactory("lark", feishu.NewFactory(feishu.RegionLark))
 	imService.RegisterAdapterFactory("slack", slack.NewFactory())
 	imService.RegisterAdapterFactory("telegram", telegram.NewFactory())
 	imService.RegisterAdapterFactory("dingtalk", dingtalk.NewFactory())
@@ -1571,9 +1573,13 @@ func initConnectorRegistry() (*datasource.ConnectorRegistry, error) {
 	registry := datasource.NewConnectorRegistry()
 
 	var errs error
-	if err := registry.Register(feishuConnector.NewConnector()); err != nil {
+	if err := registry.Register(feishuConnector.NewConnector(feishuConnector.RegionFeishu)); err != nil {
 		errs = errors.Join(errs, fmt.Errorf("register feishu connector: %w", err))
 	}
+	// Lark is Feishu's international cloud: same connector, different host/tenant.
+	if err := registry.Register(feishuConnector.NewConnector(feishuConnector.RegionLark)); err != nil {
+		errs = errors.Join(errs, fmt.Errorf("register lark connector: %w", err))
+	}
 	if err := registry.Register(notionConnector.NewConnector()); err != nil {
 		errs = errors.Join(errs, fmt.Errorf("register notion connector: %w", err))
 	}
diff --git a/internal/datasource/connector.go b/internal/datasource/connector.go
index 74dd7aaa5..53991099a 100644
--- a/internal/datasource/connector.go
+++ b/internal/datasource/connector.go
@@ -115,6 +115,14 @@ var ConnectorMetadataRegistry = map[string]ConnectorMetadata{
 		AuthType:     "oauth2",
 		Capabilities: []string{"incremental", "deletion_sync"},
 	},
+	types.ConnectorTypeLark: {
+		Type:         types.ConnectorTypeLark,
+		Name:         "Lark",
+		Description:  "Sync documents, wikis, and content from Lark (Feishu international)",
+		Priority:     0,
+		AuthType:     "oauth2",
+		Capabilities: []string{"incremental", "deletion_sync"},
+	},
 	types.ConnectorTypeNotion: {
 		Type:         types.ConnectorTypeNotion,
 		Name:         "Notion",
diff --git a/internal/datasource/connector/feishu/connector.go b/internal/datasource/connector/feishu/connector.go
index d810f3d20..3529fb311 100644
--- a/internal/datasource/connector/feishu/connector.go
+++ b/internal/datasource/connector/feishu/connector.go
@@ -15,24 +15,28 @@ import (
 	"github.com/Tencent/WeKnora/internal/types"
 )
 
-// Connector implements the datasource.Connector interface for Feishu.
-type Connector struct{}
+// Connector implements the datasource.Connector interface for Feishu and, with
+// the same code, for Lark: the two clouds expose an identical wiki/docx/drive
+// API surface. A Region picks the cloud — see region.go.
+type Connector struct {
+	region Region
+}
 
-// NewConnector creates a new Feishu connector.
-func NewConnector() *Connector {
-	return &Connector{}
+// NewConnector creates a connector for the given region (RegionFeishu or RegionLark).
+func NewConnector(region Region) *Connector {
+	return &Connector{region: region}
 }
 
 // Type returns the connector type identifier.
 func (c *Connector) Type() string {
-	return types.ConnectorTypeFeishu
+	return c.region.ConnectorType
 }
 
 const feishuWikiNodeResourceSeparator = ":"
 
 // Validate verifies that the Feishu configuration is valid by testing connectivity.
 func (c *Connector) Validate(ctx context.Context, config *types.DataSourceConfig) error {
-	feishuConfig, err := parseFeishuConfig(config)
+	feishuConfig, err := parseFeishuConfig(config, c.region)
 	if err != nil {
 		return err
 	}
@@ -57,7 +61,7 @@ func (c *Connector) Validate(ctx context.Context, config *types.DataSourceConfig
 func (c *Connector) ListResources(
 	ctx context.Context, config *types.DataSourceConfig, parentID string,
 ) ([]types.Resource, error) {
-	feishuConfig, err := parseFeishuConfig(config)
+	feishuConfig, err := parseFeishuConfig(config, c.region)
 	if err != nil {
 		return nil, err
 	}
@@ -77,7 +81,7 @@ func (c *Connector) ListResources(
 				Name:        space.Name,
 				Type:        "wiki_space",
 				Description: space.Description,
-				URL:         fmt.Sprintf("https://feishu.cn/wiki/%s", space.SpaceID),
+				URL:         c.region.wikiURL(space.SpaceID),
 				HasChildren: true,
 				Metadata: map[string]interface{}{
 					"visibility": space.Visibility,
@@ -97,7 +101,7 @@ func (c *Connector) ListResources(
 
 	resources := make([]types.Resource, 0, len(nodes))
 	for _, node := range nodes {
-		resources = append(resources, wikiNodeToResource(spaceID, node))
+		resources = append(resources, c.wikiNodeToResource(spaceID, node))
 	}
 	return resources, nil
 }
@@ -110,7 +114,7 @@ func (c *Connector) ListResources(
 func (c *Connector) ResolveResourceAncestors(
 	ctx context.Context, config *types.DataSourceConfig, resourceIDs []string,
 ) ([]string, error) {
-	feishuConfig, err := parseFeishuConfig(config)
+	feishuConfig, err := parseFeishuConfig(config, c.region)
 	if err != nil {
 		return nil, err
 	}
@@ -159,7 +163,7 @@ func (c *Connector) ResolveResourceAncestors(
 
 // FetchAll performs a full sync of all documents from the specified wiki spaces.
 func (c *Connector) FetchAll(ctx context.Context, config *types.DataSourceConfig, resourceIDs []string) ([]types.FetchedItem, error) {
-	feishuConfig, err := parseFeishuConfig(config)
+	feishuConfig, err := parseFeishuConfig(config, c.region)
 	if err != nil {
 		return nil, err
 	}
@@ -207,7 +211,7 @@ func (c *Connector) FetchAll(ctx context.Context, config *types.DataSourceConfig
 // FetchIncremental performs an incremental sync by comparing node edit times
 // against the previously recorded state.
 func (c *Connector) FetchIncremental(ctx context.Context, config *types.DataSourceConfig, cursor *types.SyncCursor) ([]types.FetchedItem, *types.SyncCursor, error) {
-	feishuConfig, err := parseFeishuConfig(config)
+	feishuConfig, err := parseFeishuConfig(config, c.region)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -400,7 +404,7 @@ func (c *Connector) fetchNodeContent(ctx context.Context, client *Client, node w
 			Content:          data,
 			ContentType:      "application/octet-stream",
 			FileName:         fileName,
-			URL:              fmt.Sprintf("https://feishu.cn/wiki/%s", node.NodeToken),
+			URL:              c.region.wikiURL(node.NodeToken),
 			UpdatedAt:        editTime,
 			SourceResourceID: resourceID,
 			Metadata:         baseMeta,
@@ -425,7 +429,7 @@ func (c *Connector) fetchNodeContent(ctx context.Context, client *Client, node w
 			Content:          data,
 			ContentType:      "application/octet-stream",
 			FileName:         fileName,
-			URL:              fmt.Sprintf("https://feishu.cn/wiki/%s", node.NodeToken),
+			URL:              c.region.wikiURL(node.NodeToken),
 			UpdatedAt:        editTime,
 			SourceResourceID: resourceID,
 			Metadata:         baseMeta,
@@ -447,7 +451,7 @@ func parseWikiResourceID(resourceID string) (spaceID string, nodeToken string) {
 	return spaceID, nodeToken
 }
 
-func wikiNodeToResource(spaceID string, node wikiNode) types.Resource {
+func (c *Connector) wikiNodeToResource(spaceID string, node wikiNode) types.Resource {
 	parentID := spaceID
 	if node.ParentNodeID != "" {
 		parentID = makeWikiNodeResourceID(spaceID, node.ParentNodeID)
@@ -467,7 +471,7 @@ func wikiNodeToResource(spaceID string, node wikiNode) types.Resource {
 		ExternalID:  makeWikiNodeResourceID(spaceID, node.NodeToken),
 		Name:        name,
 		Type:        "wiki_node",
-		URL:         fmt.Sprintf("https://feishu.cn/wiki/%s", node.NodeToken),
+		URL:         c.region.wikiURL(node.NodeToken),
 		ParentID:    parentID,
 		HasChildren: node.HasChild,
 		ModifiedAt:  modifiedAt,
@@ -480,8 +484,13 @@ func wikiNodeToResource(spaceID string, node wikiNode) types.Resource {
 	}
 }
 
-// parseFeishuConfig extracts and validates Feishu-specific configuration.
-func parseFeishuConfig(config *types.DataSourceConfig) (*Config, error) {
+// parseFeishuConfig extracts and validates Feishu/Lark-specific configuration.
+//
+// base_url stays an explicit override so existing data sources that pointed a
+// "feishu" connector at open.larksuite.com keep working; when it is unset the
+// region's own host is filled in, making the resolved Config.BaseURL concrete
+// for everything downstream.
+func parseFeishuConfig(config *types.DataSourceConfig, region Region) (*Config, error) {
 	if config == nil {
 		return nil, fmt.Errorf("config is nil")
 	}
@@ -493,11 +502,15 @@ func parseFeishuConfig(config *types.DataSourceConfig) (*Config, error) {
 
 	var feishuConfig Config
 	if err := json.Unmarshal(credBytes, &feishuConfig); err != nil {
-		return nil, fmt.Errorf("parse feishu credentials: %w", err)
+		return nil, fmt.Errorf("parse %s credentials: %w", region.ConnectorType, err)
 	}
 
 	if feishuConfig.AppID == "" || feishuConfig.AppSecret == "" {
-		return nil, fmt.Errorf("feishu app_id and app_secret are required")
+		return nil, fmt.Errorf("%s app_id and app_secret are required", region.ConnectorType)
+	}
+
+	if feishuConfig.BaseURL == "" {
+		feishuConfig.BaseURL = region.OpenBaseURL
 	}
 
 	if err := datasource.ValidateConnectorBaseURL(feishuConfig.GetBaseURL()); err != nil {
diff --git a/internal/datasource/connector/feishu/connector_test.go b/internal/datasource/connector/feishu/connector_test.go
index e3fa3b8f2..5d9dcf375 100644
--- a/internal/datasource/connector/feishu/connector_test.go
+++ b/internal/datasource/connector/feishu/connector_test.go
@@ -384,7 +384,7 @@ func TestParseFeishuConfig(t *testing.T) {
 				"app_secret": "sec1",
 				"base_url":   "https://open.feishu.cn",
 			},
-		})
+		}, RegionFeishu)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -394,7 +394,7 @@ func TestParseFeishuConfig(t *testing.T) {
 	})
 
 	t.Run("nil config", func(t *testing.T) {
-		_, err := parseFeishuConfig(nil)
+		_, err := parseFeishuConfig(nil, RegionFeishu)
 		if err == nil {
 			t.Fatal("expected error for nil config")
 		}
@@ -406,7 +406,7 @@ func TestParseFeishuConfig(t *testing.T) {
 				"app_id": "id1",
 				// missing app_secret
 			},
-		})
+		}, RegionFeishu)
 		if err == nil {
 			t.Fatal("expected error for missing app_secret")
 		}
@@ -418,7 +418,7 @@ func TestParseFeishuConfig(t *testing.T) {
 // ──────────────────────────────────────────────────────────────────────
 
 func TestConnectorType(t *testing.T) {
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	if c.Type() != types.ConnectorTypeFeishu {
 		t.Errorf("Type() = %q, want %q", c.Type(), types.ConnectorTypeFeishu)
 	}
@@ -428,7 +428,7 @@ func TestConnectorValidate(t *testing.T) {
 	ts, cfg := fakeFeishu(nil)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	err := c.Validate(context.Background(), makeConfig(cfg, nil))
 	if err != nil {
 		t.Fatalf("Validate() error: %v", err)
@@ -436,7 +436,7 @@ func TestConnectorValidate(t *testing.T) {
 }
 
 func TestConnectorValidate_BadCredentials(t *testing.T) {
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	err := c.Validate(context.Background(), &types.DataSourceConfig{
 		Credentials: map[string]interface{}{
 			"app_id":     "bad",
@@ -453,7 +453,7 @@ func TestConnectorListResources(t *testing.T) {
 	ts, cfg := fakeFeishu(nil)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	resources, err := c.ListResources(context.Background(), makeConfig(cfg, nil), "")
 	if err != nil {
 		t.Fatalf("ListResources() error: %v", err)
@@ -492,7 +492,7 @@ func TestConnectorListResources_LazyLoadsOneLevel(t *testing.T) {
 	ts, cfg := fakeFeishuHierarchy(topNodes, childNodes, "")
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 
 	// Root listing: only the space, no descendants.
 	spaces, err := c.ListResources(context.Background(), makeConfig(cfg, nil), "")
@@ -555,7 +555,7 @@ func TestConnectorResolveResourceAncestors(t *testing.T) {
 	ts, cfg := fakeFeishuHierarchy(topNodes, childNodes, "")
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 
 	// A deeply nested node resolves to its space plus every intermediate parent.
 	ancestors, err := c.ResolveResourceAncestors(
@@ -615,7 +615,7 @@ func TestFetchAll_DocxNode(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -657,7 +657,7 @@ func TestFetchAll_SheetNode(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -682,7 +682,7 @@ func TestFetchAll_BitableNode(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -706,7 +706,7 @@ func TestFetchAll_FileNode(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -736,7 +736,7 @@ func TestFetchAll_SkipsMindnoteAndSlides(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -760,7 +760,7 @@ func TestFetchAll_MixedTypes(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	items, err := c.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
@@ -783,7 +783,8 @@ func TestFetchAll_ChildNodeListErrorReturnsPartialItems(t *testing.T) {
 	ts, cfg := fakeFeishuWithChildFailure(nodes, "nt-parent")
 	defer ts.Close()
 
-	items, err := NewConnector().FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
+	conn := NewConnector(RegionFeishu)
+	items, err := conn.FetchAll(context.Background(), makeConfig(cfg, []string{"space1"}), []string{"space1"})
 	if err != nil {
 		t.Fatalf("FetchAll must not abort when one child listing fails: %v", err)
 	}
@@ -838,7 +839,8 @@ func TestFetchAll_WikiNodeResourceSyncsSelectedSubtree(t *testing.T) {
 	defer ts.Close()
 
 	resourceID := "space1:nt-root"
-	items, err := NewConnector().FetchAll(context.Background(), makeConfig(cfg, []string{resourceID}), []string{resourceID})
+	conn := NewConnector(RegionFeishu)
+	items, err := conn.FetchAll(context.Background(), makeConfig(cfg, []string{resourceID}), []string{resourceID})
 	if err != nil {
 		t.Fatalf("FetchAll() error: %v", err)
 	}
@@ -876,7 +878,7 @@ func TestFetchIncremental_FirstSync(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	dsConfig := makeConfig(cfg, []string{"space1"})
 
 	// First sync with no cursor → all items should be fetched
@@ -903,7 +905,7 @@ func TestFetchIncremental_NoChanges(t *testing.T) {
 	ts, cfg := fakeFeishu(nodes)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	dsConfig := makeConfig(cfg, []string{"space1"})
 
 	// First sync
@@ -931,7 +933,7 @@ func TestFetchIncremental_DetectsDeleted(t *testing.T) {
 	}
 	ts, cfg := fakeFeishu(allNodes)
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	dsConfig := makeConfig(cfg, []string{"space1"})
 
 	_, cursor1, err := c.FetchIncremental(context.Background(), dsConfig, nil)
@@ -971,7 +973,7 @@ func TestFetchIncremental_NoResourceIDs(t *testing.T) {
 	ts, cfg := fakeFeishu(nil)
 	defer ts.Close()
 
-	c := NewConnector()
+	c := NewConnector(RegionFeishu)
 	dsConfig := makeConfig(cfg, nil) // no resource IDs
 	dsConfig.ResourceIDs = nil
 
@@ -992,7 +994,8 @@ func TestFetchIncremental_ChildNodeListErrorReturnsPartialItemsAndCursor(t *test
 	ts, cfg := fakeFeishuWithChildFailure(nodes, "nt-parent")
 	defer ts.Close()
 
-	items, cursor, err := NewConnector().FetchIncremental(context.Background(), makeConfig(cfg, []string{"space1"}), nil)
+	conn := NewConnector(RegionFeishu)
+	items, cursor, err := conn.FetchIncremental(context.Background(), makeConfig(cfg, []string{"space1"}), nil)
 	if err != nil {
 		t.Fatalf("FetchIncremental must not abort when one child listing fails: %v", err)
 	}
@@ -1029,7 +1032,8 @@ func TestFetchIncremental_ChildNodeListErrorDoesNotDeletePreviouslySeenChildren(
 	}
 	ts, cfg := fakeFeishuHierarchy(firstNodes, firstChildren, "")
 
-	firstItems, cursor, err := NewConnector().FetchIncremental(context.Background(), makeConfig(cfg, []string{"space1"}), nil)
+	conn := NewConnector(RegionFeishu)
+	firstItems, cursor, err := conn.FetchIncremental(context.Background(), makeConfig(cfg, []string{"space1"}), nil)
 	if err != nil {
 		t.Fatalf("first sync error: %v", err)
 	}
@@ -1044,7 +1048,7 @@ func TestFetchIncremental_ChildNodeListErrorDoesNotDeletePreviouslySeenChildren(
 	ts2, cfg2 := fakeFeishuHierarchy(secondNodes, nil, "nt-parent")
 	defer ts2.Close()
 
-	items, nextCursor, err := NewConnector().FetchIncremental(context.Background(), makeConfig(cfg2, []string{"space1"}), cursor)
+	items, nextCursor, err := conn.FetchIncremental(context.Background(), makeConfig(cfg2, []string{"space1"}), cursor)
 	if err != nil {
 		t.Fatalf("partial second sync error: %v", err)
 	}
diff --git a/internal/datasource/connector/feishu/lark_e2e_test.go b/internal/datasource/connector/feishu/lark_e2e_test.go
new file mode 100644
index 000000000..a3b25f5dd
--- /dev/null
+++ b/internal/datasource/connector/feishu/lark_e2e_test.go
@@ -0,0 +1,86 @@
+package feishu
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/Tencent/WeKnora/internal/types"
+)
+
+// A Lark connector must surface wiki links on the Lark host. Before Lark became
+// its own connector type, every resource URL was hardcoded to feishu.cn, so Lark
+// users got links into a cloud their content does not live on.
+//
+// The fake server stands in for the Open Platform (base_url points at it), but
+// the resource URL is built from the region's web host, so this exercises the
+// real ListResources → wikiNodeToResource → region.wikiURL path.
+func TestListResources_ResourceURLFollowsRegion(t *testing.T) {
+	cases := []struct {
+		region      Region
+		wantURL     string
+		forbiddenIn string
+	}{
+		{RegionFeishu, "https://feishu.cn/wiki/space1", "larksuite"},
+		{RegionLark, "https://larksuite.com/wiki/space1", "feishu"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.region.Label, func(t *testing.T) {
+			ts, cfg := fakeFeishu(nil)
+			defer ts.Close()
+
+			conn := NewConnector(c.region)
+			resources, err := conn.ListResources(context.Background(), makeConfig(cfg, nil), "")
+			if err != nil {
+				t.Fatalf("ListResources: %v", err)
+			}
+			if len(resources) != 1 {
+				t.Fatalf("got %d resources, want 1", len(resources))
+			}
+			if got := resources[0].URL; got != c.wantURL {
+				t.Errorf("resource URL = %q, want %q", got, c.wantURL)
+			}
+			if strings.Contains(resources[0].URL, c.forbiddenIn) {
+				t.Errorf("%s resource URL leaks the other cloud's host: %q", c.region.Label, resources[0].URL)
+			}
+		})
+	}
+}
+
+// A Lark connector with no base_url override must reach open.larksuite.com,
+// never open.feishu.cn — the SDK-less client has no default of its own, so the
+// region is the only thing standing between a Lark app and the wrong cloud.
+func TestClient_ResolvesRegionHostWithoutOverride(t *testing.T) {
+	cases := []struct {
+		region Region
+		want   string
+	}{
+		{RegionFeishu, "https://open.feishu.cn"},
+		{RegionLark, "https://open.larksuite.com"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.region.Label, func(t *testing.T) {
+			cfg, err := parseFeishuConfig(makeConfigNoBaseURL(), c.region)
+			if err != nil {
+				t.Fatalf("parseFeishuConfig: %v", err)
+			}
+			client := NewClient(cfg)
+			if client.baseURL != c.want {
+				t.Errorf("client baseURL = %q, want %q", client.baseURL, c.want)
+			}
+		})
+	}
+}
+
+// makeConfigNoBaseURL builds credentials without base_url, so the region default
+// is what resolves.
+func makeConfigNoBaseURL() *types.DataSourceConfig {
+	return &types.DataSourceConfig{
+		Credentials: map[string]interface{}{
+			"app_id":     "cli_x",
+			"app_secret": "s",
+		},
+	}
+}
diff --git a/internal/datasource/connector/feishu/region.go b/internal/datasource/connector/feishu/region.go
new file mode 100644
index 000000000..b2898dcf0
--- /dev/null
+++ b/internal/datasource/connector/feishu/region.go
@@ -0,0 +1,57 @@
+package feishu
+
+import "github.com/Tencent/WeKnora/internal/types"
+
+// Open Platform API origins. Feishu and Lark are the same product deployed on
+// two isolated clouds; the wiki/docx/drive APIs this connector uses are
+// identical, only the host differs.
+const (
+	feishuOpenBaseURL = "https://open.feishu.cn"
+	larkOpenBaseURL   = "https://open.larksuite.com"
+)
+
+// Web origins used to build human-facing links to wiki spaces and nodes. These
+// are the end-user app hosts, not the API hosts.
+const (
+	feishuWebBaseURL = "https://feishu.cn"
+	larkWebBaseURL   = "https://larksuite.com"
+)
+
+// Region selects which cloud the connector syncs from. Apps, tenants, tokens
+// and document tokens are scoped to a single cloud and are never valid on the
+// other, so a Region is fixed per connector instance at registration.
+type Region struct {
+	// ConnectorType is the types.ConnectorType* identifier this instance serves.
+	ConnectorType string
+	// OpenBaseURL is the Open Platform API origin, without a trailing slash.
+	// It is only the default: a data source may override it via base_url.
+	OpenBaseURL string
+	// WebBaseURL is the app origin used to build wiki links shown to users.
+	WebBaseURL string
+	// Label prefixes log lines so operators can tell the clouds apart.
+	Label string
+}
+
+var (
+	// RegionFeishu is the Chinese mainland cloud (飞书).
+	RegionFeishu = Region{
+		ConnectorType: types.ConnectorTypeFeishu,
+		OpenBaseURL:   feishuOpenBaseURL,
+		WebBaseURL:    feishuWebBaseURL,
+		Label:         "Feishu",
+	}
+
+	// RegionLark is the international cloud (Lark).
+	RegionLark = Region{
+		ConnectorType: types.ConnectorTypeLark,
+		OpenBaseURL:   larkOpenBaseURL,
+		WebBaseURL:    larkWebBaseURL,
+		Label:         "Lark",
+	}
+)
+
+// wikiURL builds the user-facing link to a wiki space or node on this cloud.
+// The token is either a space_id or a node_token; both live under /wiki/.
+func (r Region) wikiURL(token string) string {
+	return r.WebBaseURL + "/wiki/" + token
+}
diff --git a/internal/datasource/connector/feishu/region_test.go b/internal/datasource/connector/feishu/region_test.go
new file mode 100644
index 000000000..f6cbab899
--- /dev/null
+++ b/internal/datasource/connector/feishu/region_test.go
@@ -0,0 +1,82 @@
+package feishu
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/Tencent/WeKnora/internal/types"
+)
+
+func TestRegions_AreDistinct(t *testing.T) {
+	if RegionFeishu.ConnectorType == RegionLark.ConnectorType {
+		t.Errorf("regions share ConnectorType %q", RegionFeishu.ConnectorType)
+	}
+	if RegionFeishu.OpenBaseURL == RegionLark.OpenBaseURL {
+		t.Errorf("regions share OpenBaseURL %q", RegionFeishu.OpenBaseURL)
+	}
+	if RegionFeishu.WebBaseURL == RegionLark.WebBaseURL {
+		t.Errorf("regions share WebBaseURL %q", RegionFeishu.WebBaseURL)
+	}
+	if RegionFeishu.ConnectorType != types.ConnectorTypeFeishu {
+		t.Errorf("RegionFeishu.ConnectorType = %q, want %q", RegionFeishu.ConnectorType, types.ConnectorTypeFeishu)
+	}
+	if RegionLark.ConnectorType != types.ConnectorTypeLark {
+		t.Errorf("RegionLark.ConnectorType = %q, want %q", RegionLark.ConnectorType, types.ConnectorTypeLark)
+	}
+}
+
+func TestConnectorType_FollowsRegion(t *testing.T) {
+	if got := NewConnector(RegionFeishu).Type(); got != types.ConnectorTypeFeishu {
+		t.Errorf("Feishu connector Type() = %q, want %q", got, types.ConnectorTypeFeishu)
+	}
+	if got := NewConnector(RegionLark).Type(); got != types.ConnectorTypeLark {
+		t.Errorf("Lark connector Type() = %q, want %q", got, types.ConnectorTypeLark)
+	}
+}
+
+// The wiki link shown in the resource picker must point at the cloud the data
+// actually lives on. Feishu's value is the pre-existing one and must not drift.
+func TestRegion_WikiURL(t *testing.T) {
+	if got, want := RegionFeishu.wikiURL("spc123"), "https://feishu.cn/wiki/spc123"; got != want {
+		t.Errorf("Feishu wikiURL = %q, want %q", got, want)
+	}
+	if got, want := RegionLark.wikiURL("spc123"), "https://larksuite.com/wiki/spc123"; got != want {
+		t.Errorf("Lark wikiURL = %q, want %q", got, want)
+	}
+	// A Lark link must never point at the Feishu host — that was the bug.
+	if strings.Contains(RegionLark.wikiURL("x"), "feishu") {
+		t.Errorf("Lark wikiURL leaks the Feishu host: %q", RegionLark.wikiURL("x"))
+	}
+}
+
+// base_url stays an override so data sources created before the lark connector
+// existed — a "feishu" connector pointed at open.larksuite.com — keep working.
+func TestParseFeishuConfig_BaseURLDefaultsToRegion(t *testing.T) {
+	cases := []struct {
+		name    string
+		region  Region
+		baseURL string
+		want    string
+	}{
+		{"feishu default", RegionFeishu, "", "https://open.feishu.cn"},
+		{"lark default", RegionLark, "", "https://open.larksuite.com"},
+		{"explicit override wins on feishu", RegionFeishu, "https://open.larksuite.com", "https://open.larksuite.com"},
+		{"explicit override wins on lark", RegionLark, "https://open.feishu.cn", "https://open.feishu.cn"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			creds := map[string]interface{}{"app_id": "cli_x", "app_secret": "s"}
+			if c.baseURL != "" {
+				creds["base_url"] = c.baseURL
+			}
+			cfg, err := parseFeishuConfig(&types.DataSourceConfig{Credentials: creds}, c.region)
+			if err != nil {
+				t.Fatalf("parseFeishuConfig: %v", err)
+			}
+			if got := cfg.GetBaseURL(); got != c.want {
+				t.Errorf("GetBaseURL() = %q, want %q", got, c.want)
+			}
+		})
+	}
+}
diff --git a/internal/handler/im.go b/internal/handler/im.go
index b3c61d685..3bf793fcc 100644
--- a/internal/handler/im.go
+++ b/internal/handler/im.go
@@ -3,6 +3,7 @@ package handler
 import (
 	"context"
 	"net/http"
+	"sort"
 	"strings"
 
 	"github.com/Tencent/WeKnora/internal/im"
@@ -13,10 +14,22 @@ import (
 
 // validIMPlatforms is the set of supported IM platforms.
 var validIMPlatforms = map[string]bool{
-	"wecom": true, "feishu": true, "slack": true, "telegram": true, "dingtalk": true, "mattermost": true,
-	"wechat": true, "qqbot": true,
+	"wecom": true, "feishu": true, "lark": true, "slack": true, "telegram": true, "dingtalk": true,
+	"mattermost": true, "wechat": true, "qqbot": true,
 }
 
+// invalidIMPlatformError is the 400 message listing the accepted platforms. It
+// is derived from validIMPlatforms so the two cannot drift apart as platforms
+// are added.
+var invalidIMPlatformError = func() string {
+	names := make([]string, 0, len(validIMPlatforms))
+	for p := range validIMPlatforms {
+		names = append(names, "'"+p+"'")
+	}
+	sort.Strings(names)
+	return "platform must be one of: " + strings.Join(names, ", ")
+}()
+
 // IMHandler handles IM platform callback requests and channel CRUD.
 type IMHandler struct {
 	imService *im.Service
@@ -60,7 +73,7 @@ func (h *IMHandler) CreateIMChannel(c *gin.Context) {
 	}
 
 	if !validIMPlatforms[req.Platform] {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "platform must be 'wecom', 'feishu', 'slack', 'telegram', 'dingtalk', 'mattermost', 'wechat' or 'qqbot'"})
+		c.JSON(http.StatusBadRequest, gin.H{"error": invalidIMPlatformError})
 		return
 	}
 
diff --git a/internal/handler/im_platform_test.go b/internal/handler/im_platform_test.go
new file mode 100644
index 000000000..3cb4daed5
--- /dev/null
+++ b/internal/handler/im_platform_test.go
@@ -0,0 +1,33 @@
+package handler
+
+import (
+	"strings"
+	"testing"
+)
+
+// The channel-creation endpoint rejects any platform without a registered
+// adapter factory, so this set must track the factories wired in the container.
+func TestValidIMPlatforms_CoversLark(t *testing.T) {
+	want := []string{
+		"wecom", "feishu", "lark", "slack", "telegram",
+		"dingtalk", "mattermost", "wechat", "qqbot",
+	}
+	for _, platform := range want {
+		if !validIMPlatforms[platform] {
+			t.Errorf("platform %q is not accepted", platform)
+		}
+	}
+	if validIMPlatforms["nonsense"] {
+		t.Error("unknown platform is accepted")
+	}
+}
+
+// The 400 message is derived from validIMPlatforms; it must not drift as
+// platforms are added.
+func TestInvalidIMPlatformError_ListsEveryPlatform(t *testing.T) {
+	for platform := range validIMPlatforms {
+		if !strings.Contains(invalidIMPlatformError, "'"+platform+"'") {
+			t.Errorf("error message omits %q: %s", platform, invalidIMPlatformError)
+		}
+	}
+}
diff --git a/internal/im/adapter.go b/internal/im/adapter.go
index 41ec2234a..034a28729 100644
--- a/internal/im/adapter.go
+++ b/internal/im/adapter.go
@@ -11,8 +11,11 @@ import (
 type Platform string
 
 const (
-	PlatformWeCom      Platform = "wecom"
-	PlatformFeishu     Platform = "feishu"
+	PlatformWeCom  Platform = "wecom"
+	PlatformFeishu Platform = "feishu"
+	// PlatformLark is Feishu's international edition (open.larksuite.com).
+	// It shares the Feishu adapter; only the API host and tenant differ.
+	PlatformLark       Platform = "lark"
 	PlatformSlack      Platform = "slack"
 	PlatformTelegram   Platform = "telegram"
 	PlatformDingtalk   Platform = "dingtalk"
@@ -67,7 +70,7 @@ type IncomingMessage struct {
 	// ThreadID is the platform-specific thread identifier.
 	// - Slack: thread_ts (top-level message uses its own timestamp)
 	// - Mattermost: root_id, or post_id if top-level
-	// - Feishu: root_id, or message_id if top-level
+	// - Feishu/Lark: root_id, or message_id if top-level
 	// - Telegram: message_thread_id (Forum Topics only)
 	// Empty for platforms without thread support (WeCom, DingTalk).
 	// In thread mode, top-level messages use their own ID as ThreadID,
diff --git a/internal/im/channel_mapping_test.go b/internal/im/channel_mapping_test.go
new file mode 100644
index 000000000..7d3bc2754
--- /dev/null
+++ b/internal/im/channel_mapping_test.go
@@ -0,0 +1,34 @@
+package im
+
+import (
+	"testing"
+
+	"github.com/Tencent/WeKnora/internal/types"
+)
+
+// Files uploaded through an IM channel are tagged with a knowledge Channel.
+// Lark deliberately shares Feishu's channel (types.ChannelFeishu documents
+// itself as "Feishu / Lark"), so Lark uploads group with Feishu ones in the KB
+// UI rather than falling through to the generic "im" channel.
+func TestIMPlatformToChannel(t *testing.T) {
+	cases := map[string]string{
+		"feishu": types.ChannelFeishu,
+		"lark":   types.ChannelFeishu,
+		"Lark":   types.ChannelFeishu, // matching is case-insensitive
+		"wechat": types.ChannelWechat,
+		"wecom":  types.ChannelWecom,
+		"wxwork": types.ChannelWecom,
+
+		"dingtalk": types.ChannelDingtalk,
+		"slack":    types.ChannelSlack,
+		// Platforms without a dedicated channel fall back to the generic one.
+		"telegram": types.ChannelIM,
+		"":         types.ChannelIM,
+	}
+
+	for platform, want := range cases {
+		if got := imPlatformToChannel(platform); got != want {
+			t.Errorf("imPlatformToChannel(%q) = %q, want %q", platform, got, want)
+		}
+	}
+}
diff --git a/internal/im/feishu/adapter.go b/internal/im/feishu/adapter.go
index 6bee2d826..0b7449542 100644
--- a/internal/im/feishu/adapter.go
+++ b/internal/im/feishu/adapter.go
@@ -1,9 +1,12 @@
-// Package feishu implements the Feishu (飞书/Lark) IM adapter for WeKnora.
+// Package feishu implements the Feishu (飞书) IM adapter for WeKnora, and with
+// it the Lark adapter: Feishu and Lark are the same product on two isolated
+// clouds (open.feishu.cn and open.larksuite.com) sharing one API surface, so a
+// single implementation serves both. A Region picks the cloud — see region.go.
 //
-// Feishu bot flow:
+// Bot flow:
 // 1. User sends a message to the bot (direct or @mention in group)
-// 2. Feishu calls our event subscription URL with the message event
-// 3. We parse the event, run QA, then call Feishu API to send reply
+// 2. Feishu/Lark calls our event subscription URL with the message event
+// 3. We parse the event, run QA, then call the Open Platform API to send a reply
 // 4. For streaming: create a card, then use CardKit streaming update API
 //
 // Reference: https://open.feishu.cn/document/server-docs/im-v1/message/create
@@ -40,6 +43,7 @@ var httpClient = &http.Client{Timeout: 10 * time.Second}
 
 // Adapter implements im.Adapter for Feishu/Lark.
 type Adapter struct {
+	region            Region
 	appID             string
 	appSecret         string
 	verificationToken string
@@ -51,10 +55,11 @@ type Adapter struct {
 	tokenExpAt time.Time
 }
 
-// NewAdapter creates a new Feishu adapter.
-func NewAdapter(appID, appSecret, verificationToken, encryptKey string) *Adapter {
+// NewAdapter creates a new adapter for the given region (RegionFeishu or RegionLark).
+func NewAdapter(region Region, appID, appSecret, verificationToken, encryptKey string) *Adapter {
 	startStreamReaper()
 	return &Adapter{
+		region:            region,
 		appID:             appID,
 		appSecret:         appSecret,
 		verificationToken: verificationToken,
@@ -62,6 +67,12 @@ func NewAdapter(appID, appSecret, verificationToken, encryptKey string) *Adapter
 	}
 }
 
+// api builds an Open Platform API URL on this adapter's cloud. path is a format
+// string beginning with "/open-apis/"; args fill its verbs.
+func (a *Adapter) api(path string, args ...any) string {
+	return a.region.OpenBaseURL + fmt.Sprintf(path, args...)
+}
+
 // startStreamReaper starts a background goroutine (once) that periodically
 // removes orphaned stream entries from feishuStreams. This prevents memory
 // leaks when EndStream is never called due to panics or pipeline errors.
@@ -102,7 +113,7 @@ func StopStreamReaper() {
 
 // Platform returns the platform identifier.
 func (a *Adapter) Platform() im.Platform {
-	return im.PlatformFeishu
+	return a.region.Platform
 }
 
 // VerifyCallback verifies the Feishu event callback by checking the verification token.
@@ -167,7 +178,7 @@ func (a *Adapter) HandleURLVerification(c *gin.Context) bool {
 	if err := json.Unmarshal(bodyBytes, &encryptedBody); err == nil && encryptedBody.Encrypt != "" {
 		decrypted, err := a.decrypt(encryptedBody.Encrypt)
 		if err != nil {
-			logger.Errorf(c.Request.Context(), "[Feishu] Failed to decrypt: %v", err)
+			logger.Errorf(c.Request.Context(), "[%s] Failed to decrypt: %v", a.region.Label, err)
 			return false
 		}
 		if err := json.Unmarshal(decrypted, &body); err != nil {
@@ -257,7 +268,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 	// Check event type
 	if eventBody.Header == nil || eventBody.Header.EventType != "im.message.receive_v1" {
 		if eventBody.Header != nil {
-			logger.Infof(c.Request.Context(), "[Feishu] Ignoring event type: %s", eventBody.Header.EventType)
+			logger.Infof(c.Request.Context(), "[%s] Ignoring event type: %s", a.region.Label, eventBody.Header.EventType)
 		}
 		return nil, nil
 	}
@@ -312,7 +323,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 		}
 
 		return &im.IncomingMessage{
-			Platform:    im.PlatformFeishu,
+			Platform:    a.region.Platform,
 			MessageType: im.MessageTypeText,
 			UserID:      openID,
 			ChatID:      chatID,
@@ -334,7 +345,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 			return nil, nil
 		}
 		return &im.IncomingMessage{
-			Platform:    im.PlatformFeishu,
+			Platform:    a.region.Platform,
 			MessageType: im.MessageTypeFile,
 			UserID:      openID,
 			ChatID:      chatID,
@@ -356,7 +367,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 			return nil, nil
 		}
 		return &im.IncomingMessage{
-			Platform:    im.PlatformFeishu,
+			Platform:    a.region.Platform,
 			MessageType: im.MessageTypeImage,
 			UserID:      openID,
 			ChatID:      chatID,
@@ -418,7 +429,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 		}
 
 		return &im.IncomingMessage{
-			Platform:    im.PlatformFeishu,
+			Platform:    a.region.Platform,
 			MessageType: im.MessageTypeText,
 			UserID:      openID,
 			ChatID:      chatID,
@@ -429,7 +440,7 @@ func (a *Adapter) ParseCallback(c *gin.Context) (*im.IncomingMessage, error) {
 		}, nil
 
 	default:
-		logger.Infof(c.Request.Context(), "[Feishu] Ignoring unsupported message type: %s", msg.MessageType)
+		logger.Infof(c.Request.Context(), "[%s] Ignoring unsupported message type: %s", a.region.Label, msg.MessageType)
 		return nil, nil
 	}
 }
@@ -514,20 +525,21 @@ func (a *Adapter) sendWithFallback(
 	// some event payloads omit it), skip straight to the fallback send API —
 	// the reply API needs a message_id in the path and can't work without one.
 	if incoming.MessageID != "" && feishuSafePathParam(incoming.MessageID) {
-		replyURL := fmt.Sprintf("https://open.feishu.cn/open-apis/im/v1/messages/%s/reply", incoming.MessageID)
+		replyURL := a.api("/open-apis/im/v1/messages/%s/reply", incoming.MessageID)
 		code, msg, err := a.postFeishuMessage(ctx, accessToken, replyURL, replyPayload)
 		switch {
 		case err != nil:
 			// Network/transport error — try the fallback since send-message is
 			// a different endpoint that might succeed.
-			logger.Warnf(ctx, "[Feishu] reply API transport error (will try fallback): %v", err)
+			logger.Warnf(ctx, "[%s] reply API transport error (will try fallback): %v", a.region.Label, err)
 		case code == 0:
 			return nil
 		case !fallbackEligibleErrorCodes[code]:
-			return fmt.Errorf("feishu reply api error: code=%d msg=%s", code, msg)
+			return fmt.Errorf("%s reply api error: code=%d msg=%s", a.region.Label, code, msg)
 		default:
 			// Fallback-eligible: retry via plain send-message API.
-			logger.Warnf(ctx, "[Feishu] reply API returned code=%d msg=%s, falling back to send-message API", code, msg)
+			logger.Warnf(ctx, "[%s] reply API returned code=%d msg=%s, falling back to send-message API",
+				a.region.Label, code, msg)
 		}
 	} else if incoming.MessageID != "" {
 		// message_id present but contains unsafe characters — refuse rather
@@ -535,17 +547,19 @@ func (a *Adapter) sendWithFallback(
 		// id suggests a tampered payload.
 		return fmt.Errorf("invalid message_id for reply API: %q", incoming.MessageID)
 	} else {
-		logger.Warnf(ctx, "[Feishu] incoming message has no message_id; replying via send-message API (will not attach to thread)")
+		logger.Warnf(ctx,
+			"[%s] incoming message has no message_id; replying via send-message API (will not attach to thread)",
+			a.region.Label)
 	}
 
 	// Fallback: plain send-message API.
-	fallbackURL := fmt.Sprintf("https://open.feishu.cn/open-apis/im/v1/messages?receive_id_type=%s", receiveIDType)
+	fallbackURL := a.api("/open-apis/im/v1/messages?receive_id_type=%s", receiveIDType)
 	code, msg, err := a.postFeishuMessage(ctx, accessToken, fallbackURL, fallbackPayload)
 	if err != nil {
 		return fmt.Errorf("send message (fallback): %w", err)
 	}
 	if code != 0 {
-		return fmt.Errorf("feishu send api error: code=%d msg=%s", code, msg)
+		return fmt.Errorf("%s send api error: code=%d msg=%s", a.region.Label, code, msg)
 	}
 	return nil
 }
@@ -616,7 +630,7 @@ func (a *Adapter) DownloadFile(ctx context.Context, msg *im.IncomingMessage) (io
 		resourceType = "image"
 	}
 
-	apiURL := fmt.Sprintf("https://open.feishu.cn/open-apis/im/v1/messages/%s/resources/%s?type=%s",
+	apiURL := a.api("/open-apis/im/v1/messages/%s/resources/%s?type=%s",
 		msg.MessageID, msg.FileKey, resourceType)
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, apiURL, nil)
@@ -700,12 +714,14 @@ func (s *feishuStreamState) nextSeq() int {
 }
 
 // buildStreamingCardJSON builds a Card JSON 2.0 with streaming_mode enabled.
-func buildStreamingCardJSON() string {
+// The placeholder text follows the region so Lark users see English rather than
+// the Chinese wording Feishu users expect.
+func buildStreamingCardJSON(region Region) string {
 	card := map[string]interface{}{
 		"schema": "2.0",
 		"config": map[string]interface{}{
 			"streaming_mode": true,
-			"summary":        map[string]string{"content": "正在思考..."},
+			"summary":        map[string]string{"content": region.ThinkingText},
 		},
 		"header": map[string]interface{}{
 			"template": "blue",
@@ -715,7 +731,7 @@ func buildStreamingCardJSON() string {
 			"elements": []map[string]interface{}{
 				{
 					"tag":        "markdown",
-					"content":    "💭 正在思考...",
+					"content":    "💭 " + region.ThinkingText,
 					"text_size":  "normal",
 					"element_id": streamingElementID,
 				},
@@ -734,7 +750,7 @@ func (a *Adapter) StartStream(ctx context.Context, incoming *im.IncomingMessage)
 	}
 
 	// 1. Create card entity via CardKit API
-	cardJSON := buildStreamingCardJSON()
+	cardJSON := buildStreamingCardJSON(a.region)
 	cardID, err := a.cardkitCreate(ctx, accessToken, cardJSON)
 	if err != nil {
 		return "", fmt.Errorf("create card: %w", err)
@@ -750,7 +766,7 @@ func (a *Adapter) StartStream(ctx context.Context, incoming *im.IncomingMessage)
 	feishuStreams[cardID] = &feishuStreamState{createdAt: time.Now()}
 	feishuStreamsMu.Unlock()
 
-	logger.Infof(ctx, "[Feishu] Streaming started: card_id=%s", cardID)
+	logger.Infof(ctx, "[%s] Streaming started: card_id=%s", a.region.Label, cardID)
 	return cardID, nil
 }
 
@@ -820,10 +836,10 @@ func (a *Adapter) EndStream(ctx context.Context, incoming *im.IncomingMessage, s
 
 	// Turn off streaming_mode to remove loading indicator
 	if err := a.cardkitSetStreaming(ctx, accessToken, streamID, false, seq); err != nil {
-		logger.Warnf(ctx, "[Feishu] Failed to disable streaming_mode: %v", err)
+		logger.Warnf(ctx, "[%s] Failed to disable streaming_mode: %v", a.region.Label, err)
 	}
 
-	logger.Infof(ctx, "[Feishu] Streaming ended: card_id=%s", streamID)
+	logger.Infof(ctx, "[%s] Streaming ended: card_id=%s", a.region.Label, streamID)
 	return nil
 }
 
@@ -838,7 +854,7 @@ func (a *Adapter) cardkitCreate(ctx context.Context, accessToken, cardJSON strin
 	})
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
-		"https://open.feishu.cn/open-apis/cardkit/v1/cards", bytes.NewReader(payload))
+		a.api("/open-apis/cardkit/v1/cards"), bytes.NewReader(payload))
 	if err != nil {
 		return "", err
 	}
@@ -915,8 +931,7 @@ func (a *Adapter) cardkitUpdateElement(ctx context.Context, accessToken, cardID,
 		"sequence": sequence,
 	})
 
-	apiURL := fmt.Sprintf("https://open.feishu.cn/open-apis/cardkit/v1/cards/%s/elements/%s/content",
-		cardID, elementID)
+	apiURL := a.api("/open-apis/cardkit/v1/cards/%s/elements/%s/content", cardID, elementID)
 	req, err := http.NewRequestWithContext(ctx, http.MethodPut, apiURL, bytes.NewReader(payload))
 	if err != nil {
 		return err
@@ -991,10 +1006,10 @@ func (a *Adapter) resolveMarkdownImages(ctx context.Context, accessToken, conten
 		alt, rawURL := sub[1], sub[2]
 		imgKey, err := a.imageKeyForURL(ctx, accessToken, rawURL)
 		if err != nil || imgKey == "" {
-			logger.Warnf(ctx, "[Feishu] image upload failed, degrading to link: url=%s err=%v", rawURL, err)
+			logger.Warnf(ctx, "[%s] image upload failed, degrading to link: url=%s err=%v", a.region.Label, rawURL, err)
 			label := alt
 			if label == "" {
-				label = "图片"
+				label = a.region.ImageFallbackLabel
 			}
 			return fmt.Sprintf("[%s](%s)", label, rawURL)
 		}
@@ -1005,7 +1020,10 @@ func (a *Adapter) resolveMarkdownImages(ctx context.Context, accessToken, conten
 // imageKeyForURL returns a Feishu image_key for the given URL, uploading it if
 // not already cached.
 func (a *Adapter) imageKeyForURL(ctx context.Context, accessToken, rawURL string) (string, error) {
-	key := imageCacheKey(rawURL)
+	// image_keys are issued per app on a single cloud. Scope the cache by app so
+	// a key uploaded by a Feishu app is never handed to a Lark app (or to another
+	// tenant's app), which would fail the card update with code=200570.
+	key := a.appID + "\x00" + imageCacheKey(rawURL)
 
 	feishuImageKeyMu.Lock()
 	if v, ok := feishuImageKeyCache[key]; ok {
@@ -1074,7 +1092,7 @@ func (a *Adapter) uploadImageFromURL(ctx context.Context, accessToken, rawURL st
 	}
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
-		"https://open.feishu.cn/open-apis/im/v1/images", &body)
+		a.api("/open-apis/im/v1/images"), &body)
 	if err != nil {
 		return "", err
 	}
@@ -1117,7 +1135,7 @@ func (a *Adapter) cardkitSetStreaming(ctx context.Context, accessToken, cardID s
 		"sequence": sequence,
 	})
 
-	apiURL := fmt.Sprintf("https://open.feishu.cn/open-apis/cardkit/v1/cards/%s/settings", cardID)
+	apiURL := a.api("/open-apis/cardkit/v1/cards/%s/settings", cardID)
 	req, err := http.NewRequestWithContext(ctx, http.MethodPatch, apiURL, bytes.NewReader(payload))
 	if err != nil {
 		return err
@@ -1160,7 +1178,7 @@ func (a *Adapter) getTenantAccessToken(ctx context.Context) (string, error) {
 	})
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
-		"https://open.feishu.cn/open-apis/auth/v3/tenant_access_token/internal",
+		a.api("/open-apis/auth/v3/tenant_access_token/internal"),
 		bytes.NewReader(payload))
 	if err != nil {
 		return "", fmt.Errorf("create request: %w", err)
diff --git a/internal/im/feishu/adapter_test.go b/internal/im/feishu/adapter_test.go
index 8eb084027..3e6e577da 100644
--- a/internal/im/feishu/adapter_test.go
+++ b/internal/im/feishu/adapter_test.go
@@ -69,7 +69,7 @@ func TestImageCacheKey_StripsQuery(t *testing.T) {
 }
 
 func TestResolveMarkdownImages_NoImageUnchanged(t *testing.T) {
-	a := &Adapter{}
+	a := &Adapter{region: RegionFeishu}
 	in := "hello **world** [link](https://example.com)"
 	if got := a.resolveMarkdownImages(context.Background(), "tok", in); got != in {
 		t.Errorf("content without image was modified: %q", got)
@@ -77,7 +77,7 @@ func TestResolveMarkdownImages_NoImageUnchanged(t *testing.T) {
 }
 
 func TestResolveMarkdownImages_FallbackToLinkOnFailure(t *testing.T) {
-	a := &Adapter{}
+	a := &Adapter{region: RegionFeishu}
 	// A direct-IP loopback URL fails SSRF validation before any network call,
 	// so the image must degrade to a plain markdown link (never left as ![]()).
 	in := "see ![diagram](http://127.0.0.1/x.png) here"
@@ -89,3 +89,16 @@ func TestResolveMarkdownImages_FallbackToLinkOnFailure(t *testing.T) {
 		t.Errorf("expected link fallback with alt text, got: %q", got)
 	}
 }
+
+// An image with no alt text falls back to the region's own label, so Lark users
+// do not get a Chinese link label.
+func TestResolveMarkdownImages_FallbackLabelFollowsRegion(t *testing.T) {
+	for _, region := range []Region{RegionFeishu, RegionLark} {
+		a := &Adapter{region: region}
+		got := a.resolveMarkdownImages(context.Background(), "tok", "![](http://127.0.0.1/x.png)")
+		want := "[" + region.ImageFallbackLabel + "](http://127.0.0.1/x.png)"
+		if got != want {
+			t.Errorf("%s fallback = %q, want %q", region.Label, got, want)
+		}
+	}
+}
diff --git a/internal/im/feishu/factory.go b/internal/im/feishu/factory.go
index 24bee0bd9..b40501cec 100644
--- a/internal/im/feishu/factory.go
+++ b/internal/im/feishu/factory.go
@@ -8,14 +8,17 @@ import (
 	"github.com/Tencent/WeKnora/internal/logger"
 )
 
-// NewFactory returns an im.AdapterFactory for Feishu (Lark) channels.
+// NewFactory returns an im.AdapterFactory for channels on the given region's
+// cloud — RegionFeishu for 飞书, RegionLark for Lark. Both use the same
+// credentials and modes; only the API host and tenant differ.
+//
 // The HTTP adapter is always created (needed for SendReply in both modes);
 // "websocket" mode additionally runs a long-connection event stream.
-func NewFactory() im.AdapterFactory {
+func NewFactory(region Region) im.AdapterFactory {
 	return func(factoryCtx context.Context, channel *im.IMChannel, msgHandler func(context.Context, *im.IncomingMessage) error) (im.Adapter, context.CancelFunc, error) {
 		creds, err := im.ParseCredentials(channel.Credentials)
 		if err != nil {
-			return nil, nil, fmt.Errorf("parse feishu credentials: %w", err)
+			return nil, nil, fmt.Errorf("parse %s credentials: %w", region.Platform, err)
 		}
 
 		appID := im.GetString(creds, "app_id")
@@ -24,7 +27,7 @@ func NewFactory() im.AdapterFactory {
 		encryptKey := im.GetString(creds, "encrypt_key")
 
 		// Always create the HTTP adapter (needed for SendReply in both modes)
-		adapter := NewAdapter(appID, appSecret, verificationToken, encryptKey)
+		adapter := NewAdapter(region, appID, appSecret, verificationToken, encryptKey)
 
 		mode := im.ResolveMode(channel, "websocket")
 
@@ -33,12 +36,13 @@ func NewFactory() im.AdapterFactory {
 			return adapter, nil, nil
 
 		case "websocket":
-			client := NewLongConnClient(appID, appSecret, msgHandler)
+			client := NewLongConnClient(region, appID, appSecret, msgHandler)
 
 			wsCtx, wsCancel := context.WithCancel(context.Background())
 			go func() {
 				if err := client.Start(wsCtx); err != nil && wsCtx.Err() == nil {
-					logger.Errorf(context.Background(), "[IM] Feishu long connection stopped for channel %s: %v", channel.ID, err)
+					logger.Errorf(context.Background(), "[IM] %s long connection stopped for channel %s: %v",
+						region.Label, channel.ID, err)
 				}
 			}()
 
@@ -54,7 +58,7 @@ func NewFactory() im.AdapterFactory {
 			return adapter, stop, nil
 
 		default:
-			return nil, nil, fmt.Errorf("unknown Feishu mode: %s", mode)
+			return nil, nil, fmt.Errorf("unknown %s mode: %s", region.Platform, mode)
 		}
 	}
 }
diff --git a/internal/im/feishu/longconn.go b/internal/im/feishu/longconn.go
index 806bc9e7c..342f42b1d 100644
--- a/internal/im/feishu/longconn.go
+++ b/internal/im/feishu/longconn.go
@@ -16,46 +16,50 @@ import (
 // MessageHandler is called when an IM message is received via long connection.
 type MessageHandler func(ctx context.Context, msg *im.IncomingMessage) error
 
-// LongConnClient manages a Feishu WebSocket long connection.
+// LongConnClient manages a Feishu/Lark WebSocket long connection.
 type LongConnClient struct {
+	region   Region
 	appID    string
 	wsClient *larkws.Client
 }
 
-// NewLongConnClient creates a Feishu long connection client.
-// When a text message arrives, it converts it to IncomingMessage and calls handler.
-func NewLongConnClient(appID, appSecret string, handler MessageHandler) *LongConnClient {
+// NewLongConnClient creates a long connection client on the given region's cloud.
+// When a message arrives, it converts it to IncomingMessage and calls handler.
+func NewLongConnClient(region Region, appID, appSecret string, handler MessageHandler) *LongConnClient {
 	// Long connection mode does not require verificationToken or encryptKey;
 	// those are only used for webhook signature verification and decryption.
 	eventHandler := dispatcher.NewEventDispatcher("", "").
 		OnP2MessageReceiveV1(func(ctx context.Context, event *larkim.P2MessageReceiveV1) error {
-			msg := convertEvent(event)
+			msg := convertEvent(region, event)
 			if msg == nil {
 				return nil
 			}
 			return handler(ctx, msg)
 		})
 
-	sdkLogger := &feishuLoggerAdapter{appID: appID}
+	sdkLogger := &feishuLoggerAdapter{region: region, appID: appID}
 
+	// WithDomain points the SDK at the region's cloud. It defaults to
+	// open.feishu.cn, so Lark apps would otherwise fail to authenticate.
 	wsClient := larkws.NewClient(appID, appSecret,
 		larkws.WithEventHandler(eventHandler),
 		larkws.WithAutoReconnect(true),
 		larkws.WithLogger(sdkLogger),
+		larkws.WithDomain(region.OpenBaseURL),
 	)
 
-	return &LongConnClient{appID: appID, wsClient: wsClient}
+	return &LongConnClient{region: region, appID: appID, wsClient: wsClient}
 }
 
 // Start begins the WebSocket long connection. It blocks until ctx is cancelled.
 func (c *LongConnClient) Start(ctx context.Context) error {
-	logger.Infof(ctx, "[IM] Feishu WebSocket connecting (app_id=%s)...", c.appID)
+	logger.Infof(ctx, "[IM] %s WebSocket connecting (app_id=%s)...", c.region.Label, c.appID)
 	return c.wsClient.Start(ctx)
 }
 
 // Close tears down the WebSocket long connection.
 //
-// This is the only reliable way to stop a Feishu long connection: the SDK's
+// This is the only reliable way to stop a long connection: the SDK's
 // Start blocks on a bare select{} and neither Start, pingLoop, nor
 // receiveMessageLoop observe the passed context, so cancelling ctx alone leaves
 // the underlying socket alive and the SDK auto-reconnecting. Client.Close()
@@ -66,48 +70,50 @@ func (c *LongConnClient) Close() {
 	c.wsClient.Close()
 }
 
-// feishuLoggerAdapter bridges the Feishu SDK logger to our unified logger,
+// feishuLoggerAdapter bridges the Feishu/Lark SDK logger to our unified logger,
 // replacing raw SDK connection messages with a consistent format.
 type feishuLoggerAdapter struct {
-	appID string
+	region Region
+	appID  string
 }
 
 func (l *feishuLoggerAdapter) Debug(ctx context.Context, args ...interface{}) {
-	logger.Debugf(ctx, "[Feishu] %s", fmt.Sprint(args...))
+	logger.Debugf(ctx, "[%s] %s", l.region.Label, fmt.Sprint(args...))
 }
 
 func (l *feishuLoggerAdapter) Info(ctx context.Context, args ...interface{}) {
 	msg := fmt.Sprint(args...)
 	if strings.HasPrefix(msg, "connected to ") {
-		logger.Infof(ctx, "[IM] Feishu WebSocket connected successfully (app_id=%s)", l.appID)
+		logger.Infof(ctx, "[IM] %s WebSocket connected successfully (app_id=%s)", l.region.Label, l.appID)
 		return
 	}
-	logger.Infof(ctx, "[Feishu] %s", msg)
+	logger.Infof(ctx, "[%s] %s", l.region.Label, msg)
 }
 
 func (l *feishuLoggerAdapter) Warn(ctx context.Context, args ...interface{}) {
-	logger.Warnf(ctx, "[Feishu] %s", fmt.Sprint(args...))
+	logger.Warnf(ctx, "[%s] %s", l.region.Label, fmt.Sprint(args...))
 }
 
 func (l *feishuLoggerAdapter) Error(ctx context.Context, args ...interface{}) {
-	logger.Errorf(ctx, "[Feishu] %s", fmt.Sprint(args...))
+	logger.Errorf(ctx, "[%s] %s", l.region.Label, fmt.Sprint(args...))
 }
 
-// convertEvent converts a Feishu SDK event to a unified IncomingMessage.
-// Supports text and file messages. Returns nil for unsupported types.
-func convertEvent(event *larkim.P2MessageReceiveV1) *im.IncomingMessage {
+// convertEvent converts a Feishu/Lark SDK event to a unified IncomingMessage.
+// Supports text, file, image and post messages. Returns nil for other types.
+func convertEvent(region Region, event *larkim.P2MessageReceiveV1) *im.IncomingMessage {
 	if event == nil || event.Event == nil || event.Event.Message == nil {
-		logger.Warnf(context.Background(), "[Feishu][RX] event dropped: nil event/event/message")
+		logger.Warnf(context.Background(), "[%s][RX] event dropped: nil event/event/message", region.Label)
 		return nil
 	}
 
 	msg := event.Event.Message
 
-	// Debug: log every raw receive event so we can see exactly what Feishu
+	// Debug: log every raw receive event so we can see exactly what the platform
 	// delivers (or doesn't). This is the single chokepoint for all message
 	// types — adding it here catches text/file/image/post uniformly.
 	logger.Infof(context.Background(),
-		"[Feishu][RX] msg_type=%q chat_type=%q chat_id=%q msg_id=%q root_id=%q parent_id=%q thread_id=%q content=%q",
+		"[%s][RX] msg_type=%q chat_type=%q chat_id=%q msg_id=%q root_id=%q parent_id=%q thread_id=%q content=%q",
+		region.Label,
 		ptrStr(msg.MessageType), ptrStr(msg.ChatType), ptrStr(msg.ChatId),
 		ptrStr(msg.MessageId), ptrStr(msg.RootId), ptrStr(msg.ParentId),
 		ptrStr(msg.ThreadId), ptrStr(msg.Content),
@@ -143,20 +149,23 @@ func convertEvent(event *larkim.P2MessageReceiveV1) *im.IncomingMessage {
 
 	switch msgType {
 	case "text":
-		return convertTextEvent(msg, openID, chatID, chatType, messageID)
+		return convertTextEvent(region, msg, openID, chatID, chatType, messageID)
 	case "file":
-		return convertFileEvent(msg, openID, chatID, chatType, messageID)
+		return convertFileEvent(region, msg, openID, chatID, chatType, messageID)
 	case "image":
-		return convertImageEvent(msg, openID, chatID, chatType, messageID)
+		return convertImageEvent(region, msg, openID, chatID, chatType, messageID)
 	case "post":
-		return convertPostEvent(msg, openID, chatID, chatType, messageID)
+		return convertPostEvent(region, msg, openID, chatID, chatType, messageID)
 	default:
 		return nil
 	}
 }
 
 // convertTextEvent handles text message type.
-func convertTextEvent(msg *larkim.EventMessage, openID, chatID string, chatType im.ChatType, messageID string) *im.IncomingMessage {
+func convertTextEvent(
+	region Region, msg *larkim.EventMessage,
+	openID, chatID string, chatType im.ChatType, messageID string,
+) *im.IncomingMessage {
 	var textContent struct {
 		Text string `json:"text"`
 	}
@@ -180,7 +189,7 @@ func convertTextEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 	}
 
 	return &im.IncomingMessage{
-		Platform:    im.PlatformFeishu,
+		Platform:    region.Platform,
 		MessageType: im.MessageTypeText,
 		UserID:      openID,
 		ChatID:      chatID,
@@ -191,7 +200,10 @@ func convertTextEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 }
 
 // convertFileEvent handles file message type.
-func convertFileEvent(msg *larkim.EventMessage, openID, chatID string, chatType im.ChatType, messageID string) *im.IncomingMessage {
+func convertFileEvent(
+	region Region, msg *larkim.EventMessage,
+	openID, chatID string, chatType im.ChatType, messageID string,
+) *im.IncomingMessage {
 	if msg.Content == nil {
 		return nil
 	}
@@ -207,7 +219,7 @@ func convertFileEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 	}
 
 	return &im.IncomingMessage{
-		Platform:    im.PlatformFeishu,
+		Platform:    region.Platform,
 		MessageType: im.MessageTypeFile,
 		UserID:      openID,
 		ChatID:      chatID,
@@ -220,7 +232,10 @@ func convertFileEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 
 // convertImageEvent handles image message type.
 // Downloads via GetMessageResource API with type=image.
-func convertImageEvent(msg *larkim.EventMessage, openID, chatID string, chatType im.ChatType, messageID string) *im.IncomingMessage {
+func convertImageEvent(
+	region Region, msg *larkim.EventMessage,
+	openID, chatID string, chatType im.ChatType, messageID string,
+) *im.IncomingMessage {
 	if msg.Content == nil {
 		return nil
 	}
@@ -235,7 +250,7 @@ func convertImageEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 	}
 
 	return &im.IncomingMessage{
-		Platform:    im.PlatformFeishu,
+		Platform:    region.Platform,
 		MessageType: im.MessageTypeImage,
 		UserID:      openID,
 		ChatID:      chatID,
@@ -248,7 +263,10 @@ func convertImageEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 
 // convertPostEvent handles rich-text (post) message type.
 // Extracts all plain text content and treats it as a text query for QA.
-func convertPostEvent(msg *larkim.EventMessage, openID, chatID string, chatType im.ChatType, messageID string) *im.IncomingMessage {
+func convertPostEvent(
+	region Region, msg *larkim.EventMessage,
+	openID, chatID string, chatType im.ChatType, messageID string,
+) *im.IncomingMessage {
 	if msg.Content == nil {
 		return nil
 	}
@@ -307,7 +325,7 @@ func convertPostEvent(msg *larkim.EventMessage, openID, chatID string, chatType
 	}
 
 	return &im.IncomingMessage{
-		Platform:    im.PlatformFeishu,
+		Platform:    region.Platform,
 		MessageType: im.MessageTypeText,
 		UserID:      openID,
 		ChatID:      chatID,
diff --git a/internal/im/feishu/region.go b/internal/im/feishu/region.go
new file mode 100644
index 000000000..1ea04caef
--- /dev/null
+++ b/internal/im/feishu/region.go
@@ -0,0 +1,49 @@
+package feishu
+
+import "github.com/Tencent/WeKnora/internal/im"
+
+// Open Platform API origins. Feishu and Lark are the same product deployed on
+// two isolated clouds; the API surface is identical, only the host differs.
+const (
+	feishuOpenBaseURL = "https://open.feishu.cn"
+	larkOpenBaseURL   = "https://open.larksuite.com"
+)
+
+// Region selects which cloud an adapter talks to. Apps, tenants, tokens and
+// resource keys (image_key, file_key, card_id) are scoped to a single cloud and
+// are never valid on the other, so a Region is fixed per channel at creation.
+type Region struct {
+	// Platform is the im.Platform reported on messages parsed by this adapter.
+	Platform im.Platform
+	// OpenBaseURL is the Open Platform API origin, without a trailing slash.
+	OpenBaseURL string
+	// Label prefixes log lines so operators can tell the clouds apart.
+	Label string
+	// ThinkingText is the placeholder shown in a streaming card before the
+	// first answer chunk arrives.
+	ThinkingText string
+	// ImageFallbackLabel labels the plain link an image degrades to when it
+	// cannot be uploaded to the platform.
+	ImageFallbackLabel string
+}
+
+var (
+	// RegionFeishu is the Chinese mainland cloud (飞书). Its users are addressed
+	// in Chinese, matching the console and app language.
+	RegionFeishu = Region{
+		Platform:           im.PlatformFeishu,
+		OpenBaseURL:        feishuOpenBaseURL,
+		Label:              "Feishu",
+		ThinkingText:       "正在思考...",
+		ImageFallbackLabel: "图片",
+	}
+
+	// RegionLark is the international cloud (Lark), addressed in English.
+	RegionLark = Region{
+		Platform:           im.PlatformLark,
+		OpenBaseURL:        larkOpenBaseURL,
+		Label:              "Lark",
+		ThinkingText:       "Thinking...",
+		ImageFallbackLabel: "Image",
+	}
+)
diff --git a/internal/im/feishu/region_test.go b/internal/im/feishu/region_test.go
new file mode 100644
index 000000000..8671927e6
--- /dev/null
+++ b/internal/im/feishu/region_test.go
@@ -0,0 +1,128 @@
+package feishu
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/Tencent/WeKnora/internal/im"
+)
+
+// The two regions must stay distinct in every dimension that reaches the
+// network or the session store: sending a Lark request to open.feishu.cn fails
+// authentication, and reporting the wrong platform merges the two clouds'
+// sessions together.
+func TestRegions_AreDistinct(t *testing.T) {
+	if RegionFeishu.OpenBaseURL == RegionLark.OpenBaseURL {
+		t.Errorf("regions share OpenBaseURL %q", RegionFeishu.OpenBaseURL)
+	}
+	if RegionFeishu.Platform == RegionLark.Platform {
+		t.Errorf("regions share Platform %q", RegionFeishu.Platform)
+	}
+	if RegionFeishu.Platform != im.PlatformFeishu {
+		t.Errorf("RegionFeishu.Platform = %q, want %q", RegionFeishu.Platform, im.PlatformFeishu)
+	}
+	if RegionLark.Platform != im.PlatformLark {
+		t.Errorf("RegionLark.Platform = %q, want %q", RegionLark.Platform, im.PlatformLark)
+	}
+}
+
+func TestRegions_BaseURLHosts(t *testing.T) {
+	cases := []struct {
+		region Region
+		want   string
+	}{
+		{RegionFeishu, "https://open.feishu.cn"},
+		{RegionLark, "https://open.larksuite.com"},
+	}
+	for _, c := range cases {
+		if c.region.OpenBaseURL != c.want {
+			t.Errorf("%s OpenBaseURL = %q, want %q", c.region.Label, c.region.OpenBaseURL, c.want)
+		}
+		if strings.HasSuffix(c.region.OpenBaseURL, "/") {
+			t.Errorf("%s OpenBaseURL has a trailing slash: %q", c.region.Label, c.region.OpenBaseURL)
+		}
+	}
+}
+
+// Every API call must land on the region's own cloud.
+func TestAdapterAPI_UsesRegionHost(t *testing.T) {
+	cases := []struct {
+		region     Region
+		wantPrefix string
+	}{
+		{RegionFeishu, "https://open.feishu.cn/open-apis/"},
+		{RegionLark, "https://open.larksuite.com/open-apis/"},
+	}
+	for _, c := range cases {
+		a := NewAdapter(c.region, "cli_app", "secret", "", "")
+
+		got := a.api("/open-apis/im/v1/messages/%s/reply", "om_1")
+		want := c.wantPrefix + "im/v1/messages/om_1/reply"
+		if got != want {
+			t.Errorf("%s api() = %q, want %q", c.region.Label, got, want)
+		}
+
+		// A path with no format verbs must survive unchanged.
+		if got := a.api("/open-apis/cardkit/v1/cards"); got != c.wantPrefix+"cardkit/v1/cards" {
+			t.Errorf("%s api() = %q, want %q", c.region.Label, got, c.wantPrefix+"cardkit/v1/cards")
+		}
+	}
+}
+
+func TestAdapterPlatform_FollowsRegion(t *testing.T) {
+	if got := NewAdapter(RegionFeishu, "a", "b", "", "").Platform(); got != im.PlatformFeishu {
+		t.Errorf("Feishu adapter Platform() = %q, want %q", got, im.PlatformFeishu)
+	}
+	if got := NewAdapter(RegionLark, "a", "b", "", "").Platform(); got != im.PlatformLark {
+		t.Errorf("Lark adapter Platform() = %q, want %q", got, im.PlatformLark)
+	}
+}
+
+// The streaming card placeholder follows the region so Lark users are not shown
+// Chinese copy.
+func TestBuildStreamingCardJSON_PlaceholderFollowsRegion(t *testing.T) {
+	for _, region := range []Region{RegionFeishu, RegionLark} {
+		raw := buildStreamingCardJSON(region)
+
+		var card struct {
+			Config struct {
+				StreamingMode bool `json:"streaming_mode"`
+				Summary       struct {
+					Content string `json:"content"`
+				} `json:"summary"`
+			} `json:"config"`
+			Body struct {
+				Elements []struct {
+					Content   string `json:"content"`
+					ElementID string `json:"element_id"`
+				} `json:"elements"`
+			} `json:"body"`
+		}
+		if err := json.Unmarshal([]byte(raw), &card); err != nil {
+			t.Fatalf("%s card is not valid JSON: %v", region.Label, err)
+		}
+
+		if !card.Config.StreamingMode {
+			t.Errorf("%s card has streaming_mode disabled", region.Label)
+		}
+		if card.Config.Summary.Content != region.ThinkingText {
+			t.Errorf("%s summary = %q, want %q", region.Label, card.Config.Summary.Content, region.ThinkingText)
+		}
+		if len(card.Body.Elements) != 1 {
+			t.Fatalf("%s card has %d elements, want 1", region.Label, len(card.Body.Elements))
+		}
+		el := card.Body.Elements[0]
+		if el.ElementID != streamingElementID {
+			t.Errorf("%s element_id = %q, want %q", region.Label, el.ElementID, streamingElementID)
+		}
+		if !strings.Contains(el.Content, region.ThinkingText) {
+			t.Errorf("%s element content %q does not contain %q", region.Label, el.Content, region.ThinkingText)
+		}
+	}
+
+	// Guard the point of the whole exercise: the copy actually differs.
+	if RegionFeishu.ThinkingText == RegionLark.ThinkingText {
+		t.Error("Feishu and Lark share ThinkingText; Lark users would see Chinese copy")
+	}
+}
diff --git a/internal/im/feishu/send_e2e_test.go b/internal/im/feishu/send_e2e_test.go
new file mode 100644
index 000000000..4322519be
--- /dev/null
+++ b/internal/im/feishu/send_e2e_test.go
@@ -0,0 +1,184 @@
+package feishu
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"testing"
+
+	"github.com/Tencent/WeKnora/internal/im"
+)
+
+// testRegion returns a Lark-shaped region pointed at a fake Open Platform, so
+// the whole send path can be driven without touching the real cloud. Region
+// carries the host as a field precisely so this is possible.
+func testRegion(baseURL string) Region {
+	r := RegionLark
+	r.OpenBaseURL = baseURL
+	return r
+}
+
+// fakeOpenPlatform records what the adapter asked for, and answers as the real
+// Open Platform would.
+type fakeOpenPlatform struct {
+	mu sync.Mutex
+	// paths records every request path in order.
+	paths []string
+	// replyAuth is the Authorization header seen on the reply call.
+	replyAuth string
+	// replyBody is the decoded JSON body of the reply call.
+	replyBody map[string]any
+	// sendBody is the decoded JSON body of the fallback send call.
+	sendBody map[string]any
+	// sendQuery is the raw query string of the fallback send call.
+	sendQuery string
+	// replyCode is returned from the reply endpoint (0 = success).
+	replyCode int
+}
+
+func (f *fakeOpenPlatform) handler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		f.mu.Lock()
+		f.paths = append(f.paths, r.URL.Path)
+		f.mu.Unlock()
+
+		switch {
+		case r.URL.Path == "/open-apis/auth/v3/tenant_access_token/internal":
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"code": 0, "tenant_access_token": "t-lark-xyz", "expire": 7200,
+			})
+
+		case strings.HasSuffix(r.URL.Path, "/reply"):
+			f.mu.Lock()
+			f.replyAuth = r.Header.Get("Authorization")
+			_ = json.NewDecoder(r.Body).Decode(&f.replyBody)
+			code := f.replyCode
+			f.mu.Unlock()
+			_ = json.NewEncoder(w).Encode(map[string]any{"code": code, "msg": "mock"})
+
+		case r.URL.Path == "/open-apis/im/v1/messages":
+			f.mu.Lock()
+			f.sendQuery = r.URL.RawQuery
+			_ = json.NewDecoder(r.Body).Decode(&f.sendBody)
+			f.mu.Unlock()
+			_ = json.NewEncoder(w).Encode(map[string]any{"code": 0, "msg": "ok"})
+
+		default:
+			http.NotFound(w, r)
+		}
+	})
+}
+
+func (f *fakeOpenPlatform) sawPath(want string) bool {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	for _, p := range f.paths {
+		if p == want {
+			return true
+		}
+	}
+	return false
+}
+
+// SendReply must fetch a token from the region's cloud and reply under the
+// original message, carrying that token as a bearer credential.
+func TestSendReply_EndToEnd_UsesRegionCloud(t *testing.T) {
+	fake := &fakeOpenPlatform{}
+	srv := httptest.NewServer(fake.handler())
+	defer srv.Close()
+
+	a := NewAdapter(testRegion(srv.URL), "cli_app", "secret", "", "")
+	incoming := &im.IncomingMessage{
+		Platform:  im.PlatformLark,
+		UserID:    "ou_user1",
+		ChatType:  im.ChatTypeDirect,
+		MessageID: "om_msg1",
+	}
+
+	if err := a.SendReply(context.Background(), incoming, &im.ReplyMessage{Content: "hello lark"}); err != nil {
+		t.Fatalf("SendReply: %v", err)
+	}
+
+	if !fake.sawPath("/open-apis/auth/v3/tenant_access_token/internal") {
+		t.Errorf("no token fetch; paths = %v", fake.paths)
+	}
+	if !fake.sawPath("/open-apis/im/v1/messages/om_msg1/reply") {
+		t.Errorf("reply did not target the message; paths = %v", fake.paths)
+	}
+	if fake.replyAuth != "Bearer t-lark-xyz" {
+		t.Errorf("reply Authorization = %q, want %q", fake.replyAuth, "Bearer t-lark-xyz")
+	}
+	if got := fake.replyBody["msg_type"]; got != "text" {
+		t.Errorf("msg_type = %v, want text", got)
+	}
+	// content is a JSON-encoded string, per the Open Platform contract.
+	var content struct {
+		Text string `json:"text"`
+	}
+	raw, _ := fake.replyBody["content"].(string)
+	if err := json.Unmarshal([]byte(raw), &content); err != nil {
+		t.Fatalf("content is not a JSON string: %q", raw)
+	}
+	if content.Text != "hello lark" {
+		t.Errorf("text = %q, want %q", content.Text, "hello lark")
+	}
+}
+
+// A group that rejects reply-in-thread (230071) must still receive the answer
+// via the plain send-message API, addressed to the chat.
+func TestSendReply_EndToEnd_FallsBackToSendAPI(t *testing.T) {
+	fake := &fakeOpenPlatform{replyCode: 230071}
+	srv := httptest.NewServer(fake.handler())
+	defer srv.Close()
+
+	a := NewAdapter(testRegion(srv.URL), "cli_app", "secret", "", "")
+	incoming := &im.IncomingMessage{
+		Platform:  im.PlatformLark,
+		UserID:    "ou_user1",
+		ChatID:    "oc_chat1",
+		ChatType:  im.ChatTypeGroup,
+		MessageID: "om_msg1",
+	}
+
+	if err := a.SendReply(context.Background(), incoming, &im.ReplyMessage{Content: "grouped"}); err != nil {
+		t.Fatalf("SendReply: %v", err)
+	}
+
+	if !fake.sawPath("/open-apis/im/v1/messages") {
+		t.Fatalf("no fallback to send-message API; paths = %v", fake.paths)
+	}
+	if fake.sendQuery != "receive_id_type=chat_id" {
+		t.Errorf("send query = %q, want receive_id_type=chat_id", fake.sendQuery)
+	}
+	if got := fake.sendBody["receive_id"]; got != "oc_chat1" {
+		t.Errorf("receive_id = %v, want oc_chat1", got)
+	}
+}
+
+// A non-fallback-eligible error must surface, not be silently swallowed.
+func TestSendReply_EndToEnd_HardErrorSurfaces(t *testing.T) {
+	fake := &fakeOpenPlatform{replyCode: 99991663} // app ticket invalid — not retryable
+	srv := httptest.NewServer(fake.handler())
+	defer srv.Close()
+
+	a := NewAdapter(testRegion(srv.URL), "cli_app", "secret", "", "")
+	incoming := &im.IncomingMessage{
+		Platform: im.PlatformLark, UserID: "ou_user1",
+		ChatType: im.ChatTypeDirect, MessageID: "om_msg1",
+	}
+
+	err := a.SendReply(context.Background(), incoming, &im.ReplyMessage{Content: "x"})
+	if err == nil {
+		t.Fatal("SendReply returned nil for a non-retryable API error")
+	}
+	if !strings.Contains(err.Error(), "99991663") {
+		t.Errorf("error %q does not mention the API code", err)
+	}
+	// The plain send API must not be tried for a hard error.
+	if fake.sawPath("/open-apis/im/v1/messages") {
+		t.Errorf("fell back to send-message API on a non-retryable error; paths = %v", fake.paths)
+	}
+}
diff --git a/internal/im/think.go b/internal/im/think.go
index 0ecd7e859..af889184b 100644
--- a/internal/im/think.go
+++ b/internal/im/think.go
@@ -187,7 +187,13 @@ type ThinkBlockStyle struct {
 }
 
 // MarkdownThinkStyle renders think blocks as markdown blockquotes.
-// Used by DingTalk and Feishu.
+// Used by DingTalk and Feishu/Lark.
+//
+// Known limitation: the headers below are Chinese for every platform, including
+// ones whose users are typically not Chinese speakers (Lark, Slack, Telegram,
+// Mattermost). Localizing them means threading a locale into
+// FormatIMDisplayContent, which is called from the shared streaming path with no
+// platform context — a cross-platform change rather than a per-platform patch.
 var MarkdownThinkStyle = ThinkBlockStyle{
 	ThinkingHeader: "> 💭 **思考中...**\n",
 	ThoughtHeader:  "> 💭 **思考过程**\n",
diff --git a/internal/im/types.go b/internal/im/types.go
index 58bced5af..17f79ad65 100644
--- a/internal/im/types.go
+++ b/internal/im/types.go
@@ -170,9 +170,11 @@ func (ch *IMChannel) computeBotIdentity() string {
 				return "wecom:wh:" + corpID + ":" + agentID
 			}
 		}
-	case "feishu":
+	// Feishu and Lark app_ids live in separate clouds and never collide, so the
+	// platform prefix keeps the same app_id on both from looking like one bot.
+	case "feishu", "lark":
 		if appID := str("app_id"); appID != "" {
-			return "feishu:" + appID
+			return ch.Platform + ":" + appID
 		}
 	case "telegram":
 		if botToken := str("bot_token"); botToken != "" {
diff --git a/internal/im/types_test.go b/internal/im/types_test.go
index 2b3dd0c4b..b3301a196 100644
--- a/internal/im/types_test.go
+++ b/internal/im/types_test.go
@@ -130,6 +130,36 @@ func TestSessionModeConstants(t *testing.T) {
 	}
 }
 
+// BotIdentity carries a unique index, so Feishu and Lark channels must never
+// derive the same identity — otherwise a Lark bot would be rejected as a
+// duplicate of an unrelated Feishu bot that happens to share an app_id.
+func TestComputeBotIdentity_FeishuAndLarkAreDistinct(t *testing.T) {
+	const creds = `{"app_id":"cli_a1b2c3","app_secret":"s"}`
+
+	feishu := &IMChannel{Platform: "feishu", Credentials: []byte(creds)}
+	lark := &IMChannel{Platform: "lark", Credentials: []byte(creds)}
+
+	feishuID := feishu.computeBotIdentity()
+	larkID := lark.computeBotIdentity()
+
+	if feishuID != "feishu:cli_a1b2c3" {
+		t.Errorf("feishu identity = %q, want %q", feishuID, "feishu:cli_a1b2c3")
+	}
+	if larkID != "lark:cli_a1b2c3" {
+		t.Errorf("lark identity = %q, want %q", larkID, "lark:cli_a1b2c3")
+	}
+	if feishuID == larkID {
+		t.Errorf("feishu and lark share identity %q", feishuID)
+	}
+}
+
+func TestComputeBotIdentity_LarkWithoutAppID(t *testing.T) {
+	ch := &IMChannel{Platform: "lark", Credentials: []byte(`{"app_secret":"s"}`)}
+	if got := ch.computeBotIdentity(); got != "" {
+		t.Errorf("identity = %q, want empty when app_id is missing", got)
+	}
+}
+
 func TestChannelSessionThreadIDField(t *testing.T) {
 	cs := ChannelSession{
 		Platform: "slack",
diff --git a/internal/types/datasource.go b/internal/types/datasource.go
index 40898cdb6..defc99c6f 100644
--- a/internal/types/datasource.go
+++ b/internal/types/datasource.go
@@ -14,7 +14,10 @@ import (
 // Data source types and constants
 const (
 	// Connector types
-	ConnectorTypeFeishu      = "feishu"
+	ConnectorTypeFeishu = "feishu"
+	// ConnectorTypeLark is Feishu's international edition (open.larksuite.com).
+	// It shares the Feishu connector; only the API host and tenant differ.
+	ConnectorTypeLark        = "lark"
 	ConnectorTypeNotion      = "notion"
 	ConnectorTypeConfluence  = "confluence"
 	ConnectorTypeYuque       = "yuque"