diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e2765c..00d5438 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,55 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ---
 
+## [0.4.0] - 2026-03-14
+
+### Added
+
+#### 🔧 服务层实现 (Phase 2)
+
+- **AgentScheduler** - 5 种调度策略
+  - RoundRobinScheduler - 轮询调度
+  - WeightedRoundRobinScheduler - 加权轮询调度（默认）
+  - LeastConnectionsScheduler - 最少连接调度
+  - LeastResponseTimeScheduler - 最快响应调度
+  - CapabilityMatchScheduler - 能力匹配调度
+
+- **MessageQueue** - 消息队列管理
+  - 消息入队/出队
+  - ACK 确认机制
+  - 重试队列管理
+  - Redis 存储支持
+
+- **SessionService** - 会话服务
+  - 创建/关闭会话
+  - Agent 分配
+  - 多 Agent 协作支持
+  - 会话活跃度追踪
+
+- **MessageService** - 消息服务
+  - 创建/获取消息
+  - 消息确认
+  - 已读标记
+  - 重试机制
+  - 消息统计
+
+- **AgentService** - Agent 服务
+  - Agent 注册/注销
+  - 状态更新
+  - 心跳管理
+  - 配置更新
+  - 离线检测
+
+### Fixed
+
+- **gateways.py** - 修复蓝图名称错误 (`gateway_bp` → `gateways_bp`)
+
+### Changed
+
+- **Dockerfile** - 添加生产环境 Docker 镜像配置
+
+---
+
 ## [0.3.0] - 2026-03-14
 
 ### Added
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..f10f8e7
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,29 @@
+# PIT Router Dockerfile
+FROM python:3.12-slim
+
+# 设置工作目录
+WORKDIR /app
+
+# 安装系统依赖
+RUN apt-get update && apt-get install -y \
+    gcc \
+    postgresql-client \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+# 复制依赖文件
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# 复制应用代码
+COPY . .
+
+# 暴露端口
+EXPOSE 9000
+
+# 健康检查
+HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
+    CMD curl -f http://localhost:9000/health || exit 1
+
+# 启动命令
+CMD ["gunicorn", "-w", "4", "-b", "0.0.0.0:9000", "-k", "gevent", "--worker-connections", "1000", "run:app"]
diff --git a/app/routes/gateways.py b/app/routes/gateways.py
index 478bae0..b719f6c 100644
--- a/app/routes/gateways.py
+++ b/app/routes/gateways.py
@@ -10,7 +10,7 @@ from app.models import db, Gateway
 gateways_bp = Blueprint('gateways', __name__)
 
 
-@gateway_bp.route('/', methods=['GET'])
+@gateways_bp.route('/', methods=['GET'])
 @jwt_required()
 def get_gateways():
     """获取 Gateway 列表"""
@@ -18,7 +18,7 @@ def get_gateways():
     return jsonify({'gateways': [g.to_dict() for g in gateways]}), 200
 
 
-@gateway_bp.route('/', methods=['POST'])
+@gateways_bp.route('/', methods=['POST'])
 @jwt_required()
 def register_gateway():
     """注册 Gateway"""
@@ -55,7 +55,7 @@ def register_gateway():
     return jsonify({'gateway': gateway.to_dict()}), 201
 
 
-@gateway_bp.route('/<gateway_id>', methods=['DELETE'])
+@gateways_bp.route('/<gateway_id>', methods=['DELETE'])
 @jwt_required()
 def delete_gateway(gateway_id):
     """注销 Gateway"""
@@ -69,7 +69,7 @@ def delete_gateway(gateway_id):
     return jsonify({'message': 'Gateway deleted'}), 200
 
 
-@gateway_bp.route('/<gateway_id>/status', methods=['GET'])
+@gateways_bp.route('/<gateway_id>/status', methods=['GET'])
 @jwt_required()
 def get_gateway_status(gateway_id):
     """获取 Gateway 状态"""
@@ -85,7 +85,7 @@ def get_gateway_status(gateway_id):
     }), 200
 
 
-@gateway_bp.route('/<gateway_id>/heartbeat', methods=['POST'])
+@gateways_bp.route('/<gateway_id>/heartbeat', methods=['POST'])
 def gateway_heartbeat(gateway_id):
     """Gateway 心跳上报"""
     gateway = Gateway.query.get(gateway_id)
diff --git a/app/services/__init__.py b/app/services/__init__.py
index b60bf1b..d081b6b 100644
--- a/app/services/__init__.py
+++ b/app/services/__init__.py
@@ -1,3 +1,16 @@
 """
 服务模块
 """
+from .scheduler import AgentScheduler
+from .message_queue import MessageQueue
+from .session_service import SessionService
+from .message_service import MessageService
+from .agent_service import AgentService
+
+__all__ = [
+    'AgentScheduler',
+    'MessageQueue',
+    'SessionService',
+    'MessageService',
+    'AgentService',
+]
diff --git a/app/services/agent_service.py b/app/services/agent_service.py
new file mode 100644
index 0000000..72eadf7
--- /dev/null
+++ b/app/services/agent_service.py
@@ -0,0 +1,198 @@
+"""
+Agent 服务
+处理 Agent 相关的业务逻辑
+"""
+from typing import Optional, List
+from datetime import datetime
+from app.models import db, Agent, Gateway
+
+
+class AgentService:
+    """Agent 服务"""
+    
+    def register_agent(
+        self,
+        name: str,
+        gateway_id: str = None,
+        model: str = None,
+        capabilities: list = None,
+        priority: int = 5,
+        weight: int = 10,
+        connection_limit: int = 5
+    ) -> Agent:
+        """注册新 Agent"""
+        agent = Agent(
+            name=name,
+            display_name=name,
+            gateway_id=gateway_id,
+            model=model,
+            capabilities=capabilities or [],
+            priority=priority,
+            weight=weight,
+            connection_limit=connection_limit,
+            status='offline'
+        )
+        
+        db.session.add(agent)
+        
+        # 更新 Gateway 的 Agent 计数
+        if gateway_id:
+            gateway = Gateway.query.get(gateway_id)
+            if gateway:
+                gateway.agent_count += 1
+        
+        db.session.commit()
+        
+        return agent
+    
+    def get_agent(self, agent_id: str) -> Optional[Agent]:
+        """获取 Agent"""
+        return Agent.query.get(agent_id)
+    
+    def get_agents(
+        self,
+        status: str = None,
+        gateway_id: str = None
+    ) -> List[Agent]:
+        """获取 Agent 列表"""
+        query = Agent.query
+        
+        if status:
+            query = query.filter_by(status=status)
+        
+        if gateway_id:
+            query = query.filter_by(gateway_id=gateway_id)
+        
+        return query.all()
+    
+    def get_available_agents(self) -> List[Agent]:
+        """获取可用 Agent 列表"""
+        return Agent.query.filter_by(status='online').filter(
+            Agent.current_sessions < Agent.connection_limit
+        ).all()
+    
+    def update_agent_status(
+        self,
+        agent_id: str,
+        status: str,
+        socket_id: str = None
+    ) -> Optional[Agent]:
+        """更新 Agent 状态"""
+        agent = Agent.query.get(agent_id)
+        if not agent:
+            return None
+        
+        agent.status = status
+        
+        if socket_id:
+            agent.socket_id = socket_id
+        
+        if status == 'online':
+            agent.last_heartbeat = datetime.utcnow()
+        
+        db.session.commit()
+        
+        return agent
+    
+    def heartbeat(self, agent_id: str) -> Optional[Agent]:
+        """Agent 心跳"""
+        agent = Agent.query.get(agent_id)
+        if not agent:
+            return None
+        
+        agent.last_heartbeat = datetime.utcnow()
+        agent.status = 'online'
+        
+        db.session.commit()
+        
+        return agent
+    
+    def update_agent_config(
+        self,
+        agent_id: str,
+        name: str = None,
+        display_name: str = None,
+        model: str = None,
+        capabilities: list = None,
+        priority: int = None,
+        weight: int = None,
+        connection_limit: int = None
+    ) -> Optional[Agent]:
+        """更新 Agent 配置"""
+        agent = Agent.query.get(agent_id)
+        if not agent:
+            return None
+        
+        if name is not None:
+            agent.name = name
+        if display_name is not None:
+            agent.display_name = display_name
+        if model is not None:
+            agent.model = model
+        if capabilities is not None:
+            agent.capabilities = capabilities
+        if priority is not None:
+            agent.priority = priority
+        if weight is not None:
+            agent.weight = weight
+        if connection_limit is not None:
+            agent.connection_limit = connection_limit
+        
+        db.session.commit()
+        
+        return agent
+    
+    def delete_agent(self, agent_id: str) -> bool:
+        """删除 Agent"""
+        agent = Agent.query.get(agent_id)
+        if not agent:
+            return False
+        
+        # 更新 Gateway 的 Agent 计数
+        if agent.gateway_id:
+            gateway = Gateway.query.get(agent.gateway_id)
+            if gateway and gateway.agent_count > 0:
+                gateway.agent_count -= 1
+        
+        db.session.delete(agent)
+        db.session.commit()
+        
+        return True
+    
+    def get_agent_stats(self) -> dict:
+        """获取 Agent 统计"""
+        total = Agent.query.count()
+        online = Agent.query.filter_by(status='online').count()
+        offline = Agent.query.filter_by(status='offline').count()
+        busy = Agent.query.filter_by(status='busy').count()
+        
+        # 总连接数
+        total_sessions = db.session.query(
+            db.func.sum(Agent.current_sessions)
+        ).scalar() or 0
+        
+        return {
+            'total': total,
+            'online': online,
+            'offline': offline,
+            'busy': busy,
+            'total_sessions': total_sessions,
+        }
+    
+    def check_offline_agents(self, timeout: int = 120) -> List[Agent]:
+        """检查超时下线的 Agent"""
+        from datetime import timedelta
+        
+        threshold = datetime.utcnow() - timedelta(seconds=timeout)
+        
+        offline_agents = Agent.query.filter(
+            Agent.status == 'online',
+            Agent.last_heartbeat < threshold
+        ).all()
+        
+        for agent in offline_agents:
+            agent.status = 'offline'
+        
+        db.session.commit()
+        
+        return offline_agents
diff --git a/app/services/message_queue.py b/app/services/message_queue.py
new file mode 100644
index 0000000..12d385e
--- /dev/null
+++ b/app/services/message_queue.py
@@ -0,0 +1,155 @@
+"""
+消息队列服务
+实现消息缓存、重试机制
+"""
+from datetime import datetime
+from typing import Optional, List
+from app.models import db, Message
+from app.extensions import redis_client
+import json
+
+
+class MessageQueue:
+    """消息队列管理"""
+    
+    # Redis 键前缀
+    PENDING_QUEUE = "pit:messages:pending"
+    RETRY_QUEUE = "pit:messages:retry"
+    MESSAGE_PREFIX = "pit:message:"
+    
+    # 配置
+    MAX_RETRY = 3
+    RETRY_DELAY = 5  # 秒
+    
+    @classmethod
+    def enqueue(cls, message: Message) -> bool:
+        """消息入队"""
+        try:
+            # 存储消息详情
+            message_key = f"{cls.MESSAGE_PREFIX}{message.id}"
+            redis_client.hset(message_key, mapping={
+                'id': message.id,
+                'session_id': message.session_id,
+                'sender_type': message.sender_type,
+                'sender_id': message.sender_id,
+                'content': message.content or '',
+                'status': message.status,
+                'retry_count': str(message.retry_count),
+                'created_at': message.created_at.isoformat() if message.created_at else '',
+            })
+            
+            # 加入待处理队列
+            redis_client.rpush(cls.PENDING_QUEUE, message.id)
+            
+            return True
+        except Exception as e:
+            print(f"Failed to enqueue message: {e}")
+            return False
+    
+    @classmethod
+    def dequeue(cls) -> Optional[dict]:
+        """消息出队"""
+        try:
+            message_id = redis_client.lpop(cls.PENDING_QUEUE)
+            if not message_id:
+                return None
+            
+            message_key = f"{cls.MESSAGE_PREFIX}{message_id}"
+            message_data = redis_client.hgetall(message_key)
+            
+            if not message_data:
+                return None
+            
+            return {
+                'id': message_data.get('id'),
+                'session_id': message_data.get('session_id'),
+                'sender_type': message_data.get('sender_type'),
+                'sender_id': message_data.get('sender_id'),
+                'content': message_data.get('content'),
+                'status': message_data.get('status'),
+                'retry_count': int(message_data.get('retry_count', 0)),
+            }
+        except Exception as e:
+            print(f"Failed to dequeue message: {e}")
+            return None
+    
+    @classmethod
+    def ack(cls, message_id: str) -> bool:
+        """消息确认"""
+        try:
+            message_key = f"{cls.MESSAGE_PREFIX}{message_id}"
+            redis_client.delete(message_key)
+            return True
+        except Exception as e:
+            print(f"Failed to ack message: {e}")
+            return False
+    
+    @classmethod
+    def retry(cls, message_id: str) -> bool:
+        """消息重试"""
+        try:
+            message_key = f"{cls.MESSAGE_PREFIX}{message_id}"
+            retry_count = redis_client.hget(message_key, 'retry_count')
+            
+            if retry_count is None:
+                return False
+            
+            retry_count = int(retry_count)
+            
+            if retry_count >= cls.MAX_RETRY:
+                # 超过最大重试次数，标记为失败
+                redis_client.hset(message_key, 'status', 'failed')
+                return False
+            
+            # 增加重试计数
+            redis_client.hset(message_key, 'retry_count', str(retry_count + 1))
+            
+            # 加入重试队列
+            redis_client.rpush(cls.RETRY_QUEUE, message_id)
+            
+            return True
+        except Exception as e:
+            print(f"Failed to retry message: {e}")
+            return False
+    
+    @classmethod
+    def get_pending_count(cls) -> int:
+        """获取待处理消息数量"""
+        try:
+            return redis_client.llen(cls.PENDING_QUEUE)
+        except:
+            return 0
+    
+    @classmethod
+    def get_retry_count(cls) -> int:
+        """获取重试消息数量"""
+        try:
+            return redis_client.llen(cls.RETRY_QUEUE)
+        except:
+            return 0
+    
+    @classmethod
+    def process_retry_queue(cls) -> List[dict]:
+        """处理重试队列"""
+        messages = []
+        
+        try:
+            while True:
+                message_id = redis_client.lpop(cls.RETRY_QUEUE)
+                if not message_id:
+                    break
+                
+                message_key = f"{cls.MESSAGE_PREFIX}{message_id}"
+                message_data = redis_client.hgetall(message_key)
+                
+                if message_data:
+                    messages.append({
+                        'id': message_data.get('id'),
+                        'session_id': message_data.get('session_id'),
+                        'content': message_data.get('content'),
+                        'retry_count': int(message_data.get('retry_count', 0)),
+                    })
+        except Exception as e:
+            print(f"Failed to process retry queue: {e}")
+        
+        return messages
diff --git a/app/services/message_service.py b/app/services/message_service.py
new file mode 100644
index 0000000..fa40765
--- /dev/null
+++ b/app/services/message_service.py
@@ -0,0 +1,167 @@
+"""
+消息服务
+处理消息相关的业务逻辑
+"""
+from typing import Optional, List
+from datetime import datetime
+from app.models import db, Message, Session
+from app.services.message_queue import MessageQueue
+import uuid
+
+
+class MessageService:
+    """消息服务"""
+    
+    def __init__(self):
+        self.queue = MessageQueue()
+    
+    def create_message(
+        self,
+        session_id: str,
+        sender_type: str,
+        sender_id: str,
+        content: str,
+        message_type: str = 'text',
+        content_type: str = 'markdown',
+        reply_to: str = None
+    ) -> Message:
+        """创建消息"""
+        message = Message(
+            id=str(uuid.uuid4()),
+            session_id=session_id,
+            sender_type=sender_type,
+            sender_id=sender_id,
+            message_type=message_type,
+            content=content,
+            content_type=content_type,
+            reply_to=reply_to,
+            status='sent',
+            ack_status='pending'
+        )
+        
+        db.session.add(message)
+        
+        # 更新会话统计
+        session = Session.query.get(session_id)
+        if session:
+            session.message_count += 1
+            session.last_active_at = datetime.utcnow()
+        
+        db.session.commit()
+        
+        # 入队等待确认
+        self.queue.enqueue(message)
+        
+        return message
+    
+    def get_message(self, message_id: str) -> Optional[Message]:
+        """获取消息"""
+        return Message.query.get(message_id)
+    
+    def get_session_messages(
+        self,
+        session_id: str,
+        limit: int = 50,
+        offset: int = 0
+    ) -> List[Message]:
+        """获取会话消息列表"""
+        return Message.query.filter_by(session_id=session_id)\
+            .order_by(Message.created_at.asc())\
+            .offset(offset)\
+            .limit(limit)\
+            .all()
+    
+    def acknowledge_message(self, message_id: str) -> Optional[Message]:
+        """确认消息已送达"""
+        message = Message.query.get(message_id)
+        if not message:
+            return None
+        
+        message.ack_status = 'acknowledged'
+        message.status = 'delivered'
+        message.delivered_at = datetime.utcnow()
+        
+        db.session.commit()
+        
+        # 从队列中移除
+        self.queue.ack(message_id)
+        
+        return message
+    
+    def mark_as_read(self, message_id: str) -> Optional[Message]:
+        """标记消息已读"""
+        message = Message.query.get(message_id)
+        if not message:
+            return None
+        
+        message.status = 'read'
+        db.session.commit()
+        
+        return message
+    
+    def mark_session_read(self, session_id: str, user_id: str) -> int:
+        """标记会话所有消息已读"""
+        # 更新数据库
+        count = Message.query.filter_by(
+            session_id=session_id,
+            status='delivered'
+        ).update({'status': 'read'})
+        
+        # 更新会话未读数
+        session = Session.query.get(session_id)
+        if session:
+            session.unread_count = 0
+        
+        db.session.commit()
+        
+        return count
+    
+    def retry_message(self, message_id: str) -> Optional[Message]:
+        """重试发送消息"""
+        message = Message.query.get(message_id)
+        if not message:
+            return None
+        
+        # 检查重试次数
+        if message.retry_count >= 3:
+            message.status = 'failed'
+            db.session.commit()
+            return None
+        
+        # 增加重试计数
+        message.retry_count += 1
+        message.status = 'sent'
+        
+        db.session.commit()
+        
+        # 加入重试队列
+        self.queue.retry(message_id)
+        
+        return message
+    
+    def get_pending_messages(self) -> List[dict]:
+        """获取待处理消息"""
+        return self.queue.process_retry_queue()
+    
+    def get_message_stats(self, session_id: str = None) -> dict:
+        """获取消息统计"""
+        query = Message.query
+        
+        if session_id:
+            query = query.filter_by(session_id=session_id)
+        
+        total = query.count()
+        sent = query.filter_by(status='sent').count()
+        delivered = query.filter_by(status='delivered').count()
+        read = query.filter_by(status='read').count()
+        failed = query.filter_by(status='failed').count()
+        
+        return {
+            'total': total,
+            'sent': sent,
+            'delivered': delivered,
+            'read': read,
+            'failed': failed,
+            'pending': self.queue.get_pending_count(),
+            'retry': self.queue.get_retry_count(),
+        }
diff --git a/app/services/scheduler.py b/app/services/scheduler.py
new file mode 100644
index 0000000..de24d41
--- /dev/null
+++ b/app/services/scheduler.py
@@ -0,0 +1,174 @@
+"""
+Agent 调度器服务
+实现多种调度策略
+"""
+from typing import List, Optional
+from app.models import Agent
+
+
+class BaseScheduler:
+    """调度器基类"""
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        """选择 Agent，子类实现"""
+        raise NotImplementedError
+
+
+class RoundRobinScheduler(BaseScheduler):
+    """轮询调度器"""
+    
+    def __init__(self):
+        self._index = 0
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        if not agents:
+            return None
+        
+        # 只选择在线的 Agent
+        online_agents = [a for a in agents if a.status == 'online']
+        if not online_agents:
+            return None
+        
+        # 轮询选择
+        agent = online_agents[self._index % len(online_agents)]
+        self._index += 1
+        return agent
+
+
+class WeightedRoundRobinScheduler(BaseScheduler):
+    """加权轮询调度器（默认）"""
+    
+    def __init__(self):
+        self._index = 0
+        self._weights = {}
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        if not agents:
+            return None
+        
+        # 只选择在线的 Agent
+        online_agents = [a for a in agents if a.status == 'online']
+        if not online_agents:
+            return None
+        
+        # 计算总权重
+        total_weight = sum(a.weight for a in online_agents)
+        if total_weight == 0:
+            return online_agents[0] if online_agents else None
+        
+        # 加权轮询
+        current_weight = self._index % total_weight
+        cumulative = 0
+        
+        for agent in online_agents:
+            cumulative += agent.weight
+            if current_weight < cumulative:
+                self._index += 1
+                return agent
+        
+        return online_agents[-1]
+
+
+class LeastConnectionsScheduler(BaseScheduler):
+    """最少连接调度器"""
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        if not agents:
+            return None
+        
+        # 只选择在线且未达连接上限的 Agent
+        available_agents = [
+            a for a in agents 
+            if a.status == 'online' and a.current_sessions < a.connection_limit
+        ]
+        
+        if not available_agents:
+            return None
+        
+        # 选择连接数最少的
+        return min(available_agents, key=lambda a: a.current_sessions)
+
+
+class LeastResponseTimeScheduler(BaseScheduler):
+    """最快响应调度器（基于最后心跳时间）"""
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        if not agents:
+            return None
+        
+        # 只选择在线的 Agent
+        online_agents = [a for a in agents if a.status == 'online']
+        if not online_agents:
+            return None
+        
+        # 选择最近有心跳的（响应快的）
+        from datetime import datetime
+        now = datetime.utcnow()
+        
+        def response_score(agent):
+            if not agent.last_heartbeat:
+                return float('inf')
+            # 最近心跳 = 分数低 = 优先选择
+            return (now - agent.last_heartbeat).total_seconds()
+        
+        return min(online_agents, key=response_score)
+
+
+class CapabilityMatchScheduler(BaseScheduler):
+    """能力匹配调度器"""
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        if not agents or not context:
+            return None
+        
+        required_capabilities = context.get('capabilities', [])
+        if not required_capabilities:
+            # 没有特殊要求，使用加权轮询
+            return WeightedRoundRobinScheduler().select_agent(agents, context)
+        
+        # 只选择在线且有对应能力的 Agent
+        matching_agents = []
+        for agent in agents:
+            if agent.status != 'online':
+                continue
+            
+            agent_caps = agent.capabilities or []
+            # 检查是否具备所有必需能力
+            if all(cap in agent_caps for cap in required_capabilities):
+                matching_agents.append(agent)
+        
+        if not matching_agents:
+            # 没有匹配的，回退到加权轮询
+            return WeightedRoundRobinScheduler().select_agent(agents, context)
+        
+        # 在匹配的 Agent 中使用加权轮询
+        return WeightedRoundRobinScheduler().select_agent(matching_agents, context)
+
+
+class AgentScheduler:
+    """Agent 调度器工厂"""
+    
+    STRATEGIES = {
+        'round_robin': RoundRobinScheduler,
+        'weighted_round_robin': WeightedRoundRobinScheduler,
+        'least_connections': LeastConnectionsScheduler,
+        'least_response_time': LeastResponseTimeScheduler,
+        'capability_match': CapabilityMatchScheduler,
+    }
+    
+    def __init__(self, strategy: str = 'weighted_round_robin'):
+        self._strategy_name = strategy
+        self._scheduler = self.STRATEGIES.get(strategy, WeightedRoundRobinScheduler)()
+    
+    def select_agent(self, agents: List[Agent], context: dict = None) -> Optional[Agent]:
+        """选择 Agent"""
+        return self._scheduler.select_agent(agents, context)
+    
+    def get_strategy(self) -> str:
+        """获取当前策略"""
+        return self._strategy_name
+    
+    @classmethod
+    def get_available_strategies(cls) -> list:
+        """获取可用策略列表"""
+        return list(cls.STRATEGIES.keys())
diff --git a/app/services/session_service.py b/app/services/session_service.py
new file mode 100644
index 0000000..afa9a38
--- /dev/null
+++ b/app/services/session_service.py
@@ -0,0 +1,168 @@
+"""
+会话服务
+处理会话相关的业务逻辑
+"""
+from typing import Optional, List
+from datetime import datetime
+from app.models import db, Session, Agent
+from app.services.scheduler import AgentScheduler
+
+
+class SessionService:
+    """会话服务"""
+    
+    def __init__(self, scheduler_strategy: str = 'weighted_round_robin'):
+        self.scheduler = AgentScheduler(scheduler_strategy)
+    
+    def create_session(
+        self,
+        user_id: str,
+        title: str = None,
+        agent_id: str = None,
+        channel_type: str = 'web',
+        context: dict = None
+    ) -> Session:
+        """创建新会话"""
+        # 如果没有指定 Agent，调度一个
+        if not agent_id:
+            from app.models import Agent
+            agents = Agent.query.all()
+            selected_agent = self.scheduler.select_agent(agents, context)
+            agent_id = selected_agent.id if selected_agent else None
+        
+        # 创建会话
+        session = Session(
+            user_id=user_id,
+            primary_agent_id=agent_id,
+            title=title or f"Session {datetime.utcnow().strftime('%Y-%m-%d %H:%M')}",
+            channel_type=channel_type,
+            status='active'
+        )
+        
+        db.session.add(session)
+        
+        # 更新 Agent 会话数
+        if agent_id:
+            agent = Agent.query.get(agent_id)
+            if agent:
+                agent.current_sessions += 1
+        
+        db.session.commit()
+        
+        return session
+    
+    def close_session(self, session_id: str, user_id: str = None) -> Optional[Session]:
+        """关闭会话"""
+        session = Session.query.get(session_id)
+        if not session:
+            return None
+        
+        # 验证权限
+        if user_id and session.user_id != user_id:
+            return None
+        
+        session.status = 'closed'
+        session.updated_at = datetime.utcnow()
+        
+        # 更新 Agent 会话数
+        if session.primary_agent_id:
+            agent = Agent.query.get(session.primary_agent_id)
+            if agent and agent.current_sessions > 0:
+                agent.current_sessions -= 1
+        
+        db.session.commit()
+        
+        return session
+    
+    def get_user_sessions(self, user_id: str, status: str = None) -> List[Session]:
+        """获取用户会话列表"""
+        query = Session.query.filter_by(user_id=user_id)
+        
+        if status:
+            query = query.filter_by(status=status)
+        
+        return query.order_by(Session.created_at.desc()).all()
+    
+    def get_session(self, session_id: str, user_id: str = None) -> Optional[Session]:
+        """获取会话详情"""
+        session = Session.query.get(session_id)
+        
+        if not session:
+            return None
+        
+        if user_id and session.user_id != user_id:
+            return None
+        
+        return session
+    
+    def update_session_activity(self, session_id: str) -> bool:
+        """更新会话活跃时间"""
+        session = Session.query.get(session_id)
+        if not session:
+            return False
+        
+        session.last_active_at = datetime.utcnow()
+        session.message_count += 1
+        db.session.commit()
+        
+        return True
+    
+    def assign_agent(self, session_id: str, agent_id: str) -> Optional[Session]:
+        """分配 Agent 到会话"""
+        session = Session.query.get(session_id)
+        if not session:
+            return None
+        
+        # 验证 Agent 是否在线
+        agent = Agent.query.get(agent_id)
+        if not agent or agent.status != 'online':
+            return None
+        
+        # 更新会话
+        old_agent_id = session.primary_agent_id
+        session.primary_agent_id = agent_id
+        
+        # 更新新旧 Agent 的会话数
+        if old_agent_id:
+            old_agent = Agent.query.get(old_agent_id)
+            if old_agent and old_agent.current_sessions > 0:
+                old_agent.current_sessions -= 1
+        
+        agent.current_sessions += 1
+        
+        db.session.commit()
+        
+        return session
+    
+    def add_participant(self, session_id: str, agent_id: str) -> Optional[Session]:
+        """添加参与 Agent"""
+        session = Session.query.get(session_id)
+        if not session:
+            return None
+        
+        # 获取当前参与列表
+        participants = session.participating_agent_ids or []
+        
+        if agent_id not in participants:
+            participants.append(agent_id)
+            session.participating_agent_ids = participants
+        
+        db.session.commit()
+        
+        return session
+    
+    def remove_participant(self, session_id: str, agent_id: str) -> Optional[Session]:
+        """移除参与 Agent"""
+        session = Session.query.get(session_id)
+        if not session:
+            return None
+        
+        participants = session.participating_agent_ids or []
+        
+        if agent_id in participants:
+            participants.remove(agent_id)
+            session.participating_agent_ids = participants
+        
+        db.session.commit()
+        
+        return session