diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignStory/AssignStoryCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignStory/AssignStoryCommandHandler.cs
index 3606f5d..bbb6839 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignStory/AssignStoryCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignStory/AssignStoryCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,7 +20,7 @@ public sealed class AssignStoryCommandHandler(
 
     public async Task<StoryDto> Handle(AssignStoryCommand request, CancellationToken cancellationToken)
     {
-        // Get the project with story
+        // Get the project with story (Global Query Filter ensures tenant isolation)
         var storyId = StoryId.From(request.StoryId);
         var project = await _projectRepository.GetProjectWithStoryAsync(storyId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignTask/AssignTaskCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignTask/AssignTaskCommandHandler.cs
index 67ff0aa..1f54cf2 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignTask/AssignTaskCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/AssignTask/AssignTaskCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -20,7 +21,7 @@ public sealed class AssignTaskCommandHandler(
 
     public async Task<TaskDto> Handle(AssignTaskCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the task
+        // Get the project containing the task (Global Query Filter ensures tenant isolation)
         var taskId = TaskId.From(request.TaskId);
         var project = await _projectRepository.GetProjectWithTaskAsync(taskId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateEpic/CreateEpicCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateEpic/CreateEpicCommandHandler.cs
index e5277df..b53a15d 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateEpic/CreateEpicCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateEpic/CreateEpicCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,14 +20,14 @@ public sealed class CreateEpicCommandHandler(
 
     public async Task<EpicDto> Handle(CreateEpicCommand request, CancellationToken cancellationToken)
     {
-        // Get the project
+        // Get the project (Global Query Filter ensures tenant isolation)
         var projectId = ProjectId.From(request.ProjectId);
         var project = await _projectRepository.GetByIdAsync(projectId, cancellationToken);
 
         if (project == null)
             throw new NotFoundException("Project", request.ProjectId);
 
-        // Create epic through aggregate root
+        // Create epic through aggregate root (Project passes its TenantId)
         var createdById = UserId.From(request.CreatedBy);
         var epic = project.CreateEpic(request.Name, request.Description, createdById);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateStory/CreateStoryCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateStory/CreateStoryCommandHandler.cs
index 0ac7695..aa814c2 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateStory/CreateStoryCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateStory/CreateStoryCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,7 +20,7 @@ public sealed class CreateStoryCommandHandler(
 
     public async Task<StoryDto> Handle(CreateStoryCommand request, CancellationToken cancellationToken)
     {
-        // Get the project with epic
+        // Get the project with epic (Global Query Filter ensures tenant isolation)
         var epicId = EpicId.From(request.EpicId);
         var project = await _projectRepository.GetProjectWithEpicAsync(epicId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateTask/CreateTaskCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateTask/CreateTaskCommandHandler.cs
index 561bdaa..7bbe88e 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateTask/CreateTaskCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/CreateTask/CreateTaskCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -20,7 +21,7 @@ public sealed class CreateTaskCommandHandler(
 
     public async Task<TaskDto> Handle(CreateTaskCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the story
+        // Get the project containing the story (Global Query Filter ensures tenant isolation)
         var storyId = StoryId.From(request.StoryId);
         var project = await _projectRepository.GetProjectWithStoryAsync(storyId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteStory/DeleteStoryCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteStory/DeleteStoryCommandHandler.cs
index 9928c1f..5e54f06 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteStory/DeleteStoryCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteStory/DeleteStoryCommandHandler.cs
@@ -1,4 +1,5 @@
 using MediatR;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -18,7 +19,7 @@ public sealed class DeleteStoryCommandHandler(
 
     public async Task<Unit> Handle(DeleteStoryCommand request, CancellationToken cancellationToken)
     {
-        // Get the project with story
+        // Get the project with story (Global Query Filter ensures tenant isolation)
         var storyId = StoryId.From(request.StoryId);
         var project = await _projectRepository.GetProjectWithStoryAsync(storyId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteTask/DeleteTaskCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteTask/DeleteTaskCommandHandler.cs
index c904449..6c2c146 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteTask/DeleteTaskCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/DeleteTask/DeleteTaskCommandHandler.cs
@@ -1,4 +1,5 @@
 using MediatR;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,7 +20,7 @@ public sealed class DeleteTaskCommandHandler(
 
     public async Task<Unit> Handle(DeleteTaskCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the task
+        // Get the project containing the task (Global Query Filter ensures tenant isolation)
         var taskId = TaskId.From(request.TaskId);
         var project = await _projectRepository.GetProjectWithTaskAsync(taskId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateEpic/UpdateEpicCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateEpic/UpdateEpicCommandHandler.cs
index 5f318ad..0eada19 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateEpic/UpdateEpicCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateEpic/UpdateEpicCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,7 +20,7 @@ public sealed class UpdateEpicCommandHandler(
 
     public async Task<EpicDto> Handle(UpdateEpicCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the epic
+        // Get the project containing the epic (Global Query Filter ensures tenant isolation)
         var epicId = EpicId.From(request.EpicId);
         var project = await _projectRepository.GetProjectWithEpicAsync(epicId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateStory/UpdateStoryCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateStory/UpdateStoryCommandHandler.cs
index 5c7dcd9..0e8b967 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateStory/UpdateStoryCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateStory/UpdateStoryCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -19,7 +20,7 @@ public sealed class UpdateStoryCommandHandler(
 
     public async Task<StoryDto> Handle(UpdateStoryCommand request, CancellationToken cancellationToken)
     {
-        // Get the project with story
+        // Get the project with story (Global Query Filter ensures tenant isolation)
         var storyId = StoryId.From(request.StoryId);
         var project = await _projectRepository.GetProjectWithStoryAsync(storyId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTask/UpdateTaskCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTask/UpdateTaskCommandHandler.cs
index 52116cc..16e6c74 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTask/UpdateTaskCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTask/UpdateTaskCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -20,7 +21,7 @@ public sealed class UpdateTaskCommandHandler(
 
     public async Task<TaskDto> Handle(UpdateTaskCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the task
+        // Get the project containing the task (Global Query Filter ensures tenant isolation)
         var taskId = TaskId.From(request.TaskId);
         var project = await _projectRepository.GetProjectWithTaskAsync(taskId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTaskStatus/UpdateTaskStatusCommandHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTaskStatus/UpdateTaskStatusCommandHandler.cs
index 61c71d7..b3287e0 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTaskStatus/UpdateTaskStatusCommandHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Commands/UpdateTaskStatus/UpdateTaskStatusCommandHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -20,7 +21,7 @@ public sealed class UpdateTaskStatusCommandHandler(
 
     public async Task<TaskDto> Handle(UpdateTaskStatusCommand request, CancellationToken cancellationToken)
     {
-        // Get the project containing the task
+        // Get the project containing the task (Global Query Filter ensures tenant isolation)
         var taskId = TaskId.From(request.TaskId);
         var project = await _projectRepository.GetProjectWithTaskAsync(taskId, cancellationToken);
 
diff --git a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Queries/GetEpicById/GetEpicByIdQueryHandler.cs b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Queries/GetEpicById/GetEpicByIdQueryHandler.cs
index 0be1cf9..aafa8e6 100644
--- a/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Queries/GetEpicById/GetEpicByIdQueryHandler.cs
+++ b/colaflow-api/src/Modules/ProjectManagement/ColaFlow.Modules.ProjectManagement.Application/Queries/GetEpicById/GetEpicByIdQueryHandler.cs
@@ -1,5 +1,6 @@
 using MediatR;
 using ColaFlow.Modules.ProjectManagement.Application.DTOs;
+using ColaFlow.Modules.ProjectManagement.Application.Common.Interfaces;
 using ColaFlow.Modules.ProjectManagement.Domain.Repositories;
 using ColaFlow.Modules.ProjectManagement.Domain.ValueObjects;
 using ColaFlow.Modules.ProjectManagement.Domain.Exceptions;
@@ -9,13 +10,15 @@ namespace ColaFlow.Modules.ProjectManagement.Application.Queries.GetEpicById;
 /// <summary>
 /// Handler for GetEpicByIdQuery
 /// </summary>
-public sealed class GetEpicByIdQueryHandler(IProjectRepository projectRepository)
+public sealed class GetEpicByIdQueryHandler(
+    IProjectRepository projectRepository)
     : IRequestHandler<GetEpicByIdQuery, EpicDto>
 {
     private readonly IProjectRepository _projectRepository = projectRepository ?? throw new ArgumentNullException(nameof(projectRepository));
 
     public async Task<EpicDto> Handle(GetEpicByIdQuery request, CancellationToken cancellationToken)
     {
+        // Get the project containing the epic (Global Query Filter ensures tenant isolation)
         var epicId = EpicId.From(request.EpicId);
         var project = await _projectRepository.GetProjectWithEpicAsync(epicId, cancellationToken);