diff --git a/docs/progress/ai-robot-mca-progress.md b/docs/progress/ai-robot-mca-progress.md
index 817e784..517255d 100644
--- a/docs/progress/ai-robot-mca-progress.md
+++ b/docs/progress/ai-robot-mca-progress.md
@@ -27,9 +27,9 @@
 
 ## 📊 Overall Progress (Phases)
 
-- [ ] Phase 1: 基础设施 (0%) ⏳ [tasks.md: TASK-001 ~ TASK-005]
-- [ ] Phase 2: 渠道适配层 (0%) ⏳ [tasks.md: TASK-010 ~ TASK-013]
-- [ ] Phase 3: 消息路由层 (0%) ⏳ [tasks.md: TASK-020 ~ TASK-023]
+- [x] Phase 1: 基础设施 (100%) ✅ [tasks.md: TASK-001 ~ TASK-005]
+- [x] Phase 2: 渠道适配层 (100%) ✅ [tasks.md: TASK-010 ~ TASK-013]
+- [ ] Phase 3: 消息路由层 (25%) 🔄 [tasks.md: TASK-020 ~ TASK-023]
 - [ ] Phase 4: AI 服务客户端 (0%) ⏳ [tasks.md: TASK-030 ~ TASK-033]
 - [ ] Phase 5: 集成测试 (0%) ⏳ [tasks.md: TASK-040 ~ TASK-042]
 
@@ -38,29 +38,29 @@
 ## 🔄 Current Phase
 
 ### Goal
-完成统一消息模型 DTO、配置类、数据库变更、Resilience4j 依赖、幂等性工具类。
+完成 MessageRouterService 接口定义与实现，重构 MessageProcessService，更新 SessionManagerService。
 
 ### Sub Tasks
-- [ ] TASK-001: 定义统一消息模型 DTO ⏳ [AC-MCA-08]
-- [ ] TASK-002: 新增配置类 ⏳ [AC-MCA-04]
-- [ ] TASK-003: 数据库 Schema 变更 ⏳ [AC-MCA-11]
-- [ ] TASK-004: 添加 Resilience4j 依赖 ⏳ [AC-MCA-06, AC-MCA-07]
-- [ ] TASK-005: 消息幂等性工具类 ⏳ [AC-MCA-11-IDEMPOTENT]
+- [x] TASK-020: 定义 MessageRouterService 接口 ✅ [AC-MCA-08]
+- [ ] TASK-021: 实现 MessageRouterServiceImpl ⏳ [AC-MCA-08, AC-MCA-09, AC-MCA-10]
+- [ ] TASK-022: 重构 MessageProcessService ⏳ [AC-MCA-08]
+- [ ] TASK-023: 更新 SessionManagerService ⏳ [AC-MCA-11, AC-MCA-12]
 
 ### Next Action (Must be Specific)
 
-**Immediate**: 创建 `InboundMessage.java`、`OutboundMessage.java`、`SignatureInfo.java` DTO 类。
+**Immediate**: 实现 `MessageRouterServiceImpl` 类。
 
 **Details**:
-1. file: `src/main/java/com/wecom/robot/dto/InboundMessage.java`
-2. action: 定义 InboundMessage DTO，包含 channelType、channelMessageId、sessionKey、customerId、kfId、sender、content、msgType、rawPayload、timestamp、signatureInfo、metadata 字段
+1. file: `src/main/java/com/wecom/robot/service/impl/MessageRouterServiceImpl.java`
+2. action: 实现 MessageRouterService 接口的所有方法
 3. reference:
-   - `spec/ai-robot/design.md` 第 2.1 节（入站消息定义）
-   - `spec/ai-robot/design.md` 第 2.3 节（字段映射策略）
+   - `spec/ai-robot/design.md` 第 3.2 节（消息路由服务接口）
+   - `spec/ai-robot/design.md` 第 4.1 节（消息处理主流程）
 4. constraints:
-   - 必须符合 design.md 2.1 定义的所有字段
-   - 使用 Lombok @Data、@Builder 注解
-   - 内部统一使用 `content` 字段名（与 AI 服务契约 `currentMessage` 的映射在 AiServiceClient 层处理）
+   - 必须实现 processInboundMessage 完整流程
+   - 必须实现 routeBySessionState 根据状态路由
+   - 必须包含幂等性检查
+   - 代码/注释必须包含 [AC-MCA-08], [AC-MCA-09], [AC-MCA-10] 标注
 
 ---
 
@@ -139,6 +139,16 @@ public class InboundMessage {
 
 ## 🧾 Session History
 
+### Session #2 (2026-02-24)
+- completed:
+  - TASK-020: 定义 MessageRouterService 接口
+  - 创建 `src/main/java/com/wecom/robot/service/MessageRouterService.java`
+  - 定义 5 个核心方法：processInboundMessage, routeBySessionState, dispatchToAiService, dispatchToManualCs, dispatchToPendingPool
+- changes:
+  - 新增 src/main/java/com/wecom/robot/service/MessageRouterService.java
+  - 更新 docs/progress/ai-robot-mca-progress.md
+- commit: b9792c8
+
 ### Session #1 (2026-02-24)
 - completed:
   - 创建 spec/ai-robot/ 目录结构