diff --git a/colaflow-api/src/ColaFlow.API/Program.cs b/colaflow-api/src/ColaFlow.API/Program.cs
index 16cb7ad..f01e7cf 100644
--- a/colaflow-api/src/ColaFlow.API/Program.cs
+++ b/colaflow-api/src/ColaFlow.API/Program.cs
@@ -7,6 +7,7 @@ using ColaFlow.Modules.Identity.Application;
 using ColaFlow.Modules.Identity.Infrastructure;
 using ColaFlow.Modules.Identity.Infrastructure.Persistence;
 using ColaFlow.Modules.Mcp.Infrastructure.Extensions;
+using ColaFlow.Modules.Mcp.Infrastructure.Hubs;
 using ColaFlow.Modules.ProjectManagement.Infrastructure.Persistence;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.EntityFrameworkCore;
diff --git a/colaflow-api/src/ColaFlow.API/Hubs/McpNotificationHub.cs b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Hubs/McpNotificationHub.cs
similarity index 59%
rename from colaflow-api/src/ColaFlow.API/Hubs/McpNotificationHub.cs
rename to colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Hubs/McpNotificationHub.cs
index 593ee57..3901163 100644
--- a/colaflow-api/src/ColaFlow.API/Hubs/McpNotificationHub.cs
+++ b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Hubs/McpNotificationHub.cs
@@ -1,14 +1,15 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.Logging;
 
-namespace ColaFlow.API.Hubs;
+namespace ColaFlow.Modules.Mcp.Infrastructure.Hubs;
 
 /// <summary>
 /// SignalR Hub for MCP real-time notifications
 /// Supports notifying AI agents and users about PendingChange status updates
 /// </summary>
 [Authorize]
-public class McpNotificationHub : BaseHub
+public class McpNotificationHub : Hub
 {
     private readonly ILogger<McpNotificationHub> _logger;
 
@@ -19,15 +20,26 @@ public class McpNotificationHub : BaseHub
 
     public override async Task OnConnectedAsync()
     {
-        var connectionId = Context.ConnectionId;
-        var userId = GetCurrentUserId();
-        var tenantId = GetCurrentTenantId();
+        try
+        {
+            var connectionId = Context.ConnectionId;
+            var userId = GetCurrentUserId();
+            var tenantId = GetCurrentTenantId();
 
-        _logger.LogInformation(
-            "MCP client connected - ConnectionId={ConnectionId}, UserId={UserId}, TenantId={TenantId}",
-            connectionId, userId, tenantId);
+            // Automatically join tenant group (tenant isolation)
+            await Groups.AddToGroupAsync(Context.ConnectionId, GetTenantGroupName(tenantId));
 
-        await base.OnConnectedAsync();
+            _logger.LogInformation(
+                "MCP client connected - ConnectionId={ConnectionId}, UserId={UserId}, TenantId={TenantId}",
+                connectionId, userId, tenantId);
+
+            await base.OnConnectedAsync();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "MCP client connection error");
+            Context.Abort();
+        }
     }
 
     public override async Task OnDisconnectedAsync(Exception? exception)
@@ -78,11 +90,37 @@ public class McpNotificationHub : BaseHub
             Context.ConnectionId, groupName, pendingChangeId);
     }
 
-    /// <summary>
-    /// Get the SignalR group name for a pending change
-    /// </summary>
-    /// <param name="pendingChangeId">The pending change ID</param>
-    /// <returns>The group name</returns>
+    // Helper methods (copied from BaseHub to avoid cross-layer dependency)
+    protected Guid GetCurrentUserId()
+    {
+        var userIdClaim = Context.User?.FindFirst("sub")
+            ?? Context.User?.FindFirst("user_id");
+
+        if (userIdClaim == null || !Guid.TryParse(userIdClaim.Value, out var userId))
+        {
+            throw new UnauthorizedAccessException("User ID not found in token");
+        }
+
+        return userId;
+    }
+
+    protected Guid GetCurrentTenantId()
+    {
+        var tenantIdClaim = Context.User?.FindFirst("tenant_id");
+
+        if (tenantIdClaim == null || !Guid.TryParse(tenantIdClaim.Value, out var tenantId))
+        {
+            throw new UnauthorizedAccessException("Tenant ID not found in token");
+        }
+
+        return tenantId;
+    }
+
+    protected string GetTenantGroupName(Guid tenantId)
+    {
+        return $"tenant-{tenantId}";
+    }
+
     private static string GetPendingChangeGroupName(Guid pendingChangeId)
     {
         return $"pending-change-{pendingChangeId}";
diff --git a/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Services/McpNotificationService.cs b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Services/McpNotificationService.cs
index 0e9527c..0b7a71f 100644
--- a/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Services/McpNotificationService.cs
+++ b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Services/McpNotificationService.cs
@@ -1,6 +1,6 @@
-using ColaFlow.API.Hubs;
 using ColaFlow.Modules.Mcp.Application.DTOs.Notifications;
 using ColaFlow.Modules.Mcp.Application.Services;
+using ColaFlow.Modules.Mcp.Infrastructure.Hubs;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Logging;
 
diff --git a/colaflow-api/tests/Modules/Mcp/ColaFlow.Modules.Mcp.Tests/Services/McpNotificationServiceTests.cs b/colaflow-api/tests/Modules/Mcp/ColaFlow.Modules.Mcp.Tests/Services/McpNotificationServiceTests.cs
index 5473bb7..8e77157 100644
--- a/colaflow-api/tests/Modules/Mcp/ColaFlow.Modules.Mcp.Tests/Services/McpNotificationServiceTests.cs
+++ b/colaflow-api/tests/Modules/Mcp/ColaFlow.Modules.Mcp.Tests/Services/McpNotificationServiceTests.cs
@@ -1,5 +1,5 @@
-using ColaFlow.API.Hubs;
 using ColaFlow.Modules.Mcp.Application.DTOs.Notifications;
+using ColaFlow.Modules.Mcp.Infrastructure.Hubs;
 using ColaFlow.Modules.Mcp.Infrastructure.Services;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Logging;