diff --git a/openspec/changes/migrate-to-external-api-authentication/proposal.md b/openspec/changes/migrate-to-external-api-authentication/proposal.md
index 98939b0..0737d79 100644
--- a/openspec/changes/migrate-to-external-api-authentication/proposal.md
+++ b/openspec/changes/migrate-to-external-api-authentication/proposal.md
@@ -72,25 +72,118 @@ By migrating to the external API authentication service at https://pj-auth-api.v
 ```
 
 ### Database Schema Changes
-- **users table modifications**:
-  - Remove/deprecate `hashed_password` column (keep for rollback)
-  - Add `external_user_id` (VARCHAR 255) - Store Azure AD user ID
-  - Add `display_name` (VARCHAR 255) - Store user display name from API
-  - Add `azure_email` (VARCHAR 255) - Store Azure AD email
-  - Add `last_token_refresh` (DATETIME) - Track token refresh timing
-  - Keep `username` for backward compatibility (can be email)
+
+**Complete Redesign (No backward compatibility needed)**:
+
+1. **users table (redesigned)**:
+   ```sql
+   CREATE TABLE users (
+     id INT PRIMARY KEY AUTO_INCREMENT,
+     email VARCHAR(255) UNIQUE NOT NULL,  -- Primary identifier from Azure AD
+     display_name VARCHAR(255),            -- Display name from API response
+     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+     last_login TIMESTAMP,
+     is_active BOOLEAN DEFAULT TRUE
+   );
+   ```
+   Note: No Azure AD ID storage needed - email is sufficient as unique identifier
+
+2. **ocr_tasks table (new - for task history)**:
+   ```sql
+   CREATE TABLE ocr_tasks (
+     id INT PRIMARY KEY AUTO_INCREMENT,
+     user_id INT NOT NULL,                 -- Foreign key to users table
+     task_id VARCHAR(255) UNIQUE,          -- Unique task identifier
+     filename VARCHAR(255),
+     file_type VARCHAR(50),
+     status ENUM('pending', 'processing', 'completed', 'failed'),
+     result_json_path VARCHAR(500),
+     result_markdown_path VARCHAR(500),
+     error_message TEXT,
+     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+     updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+     completed_at TIMESTAMP NULL,
+     file_deleted BOOLEAN DEFAULT FALSE,   -- Track if files were auto-deleted
+     FOREIGN KEY (user_id) REFERENCES users(id),
+     INDEX idx_user_status (user_id, status),
+     INDEX idx_created (created_at)
+   );
+   ```
+
+3. **task_files table (for multiple files per task)**:
+   ```sql
+   CREATE TABLE task_files (
+     id INT PRIMARY KEY AUTO_INCREMENT,
+     task_id INT NOT NULL,
+     original_name VARCHAR(255),
+     stored_path VARCHAR(500),
+     file_size BIGINT,
+     mime_type VARCHAR(100),
+     FOREIGN KEY (task_id) REFERENCES ocr_tasks(id) ON DELETE CASCADE
+   );
+   ```
 
 ### Session Management
 - Store external API tokens in session/cache instead of local JWT
 - Implement token refresh mechanism based on `expires_in` field
 - Use `expiresAt` timestamp for token expiration validation
 
+## New Features: User Task Isolation and History
+
+### Task Isolation
+- **Principle**: Each user can only see and access their own tasks
+- **Implementation**: All task queries filtered by `user_id` at API level
+- **Security**: Enforce user context validation in all task-related endpoints
+
+### Task History Features
+1. **Task Status Tracking**:
+   - View pending tasks (waiting to process)
+   - View processing tasks (currently running)
+   - View completed tasks (with results available)
+   - View failed tasks (with error messages)
+
+2. **Historical Query Capabilities**:
+   - Search tasks by filename
+   - Filter by date range
+   - Filter by status
+   - Sort by creation/completion time
+   - Pagination for large result sets
+
+3. **Task Management**:
+   - Download original files (if not auto-deleted)
+   - Download results (JSON, Markdown, PDF exports)
+   - Re-process failed tasks
+   - Delete old tasks manually
+
+### Frontend UI Changes
+1. **New Components**:
+   - Task History page/tab
+   - Task filters and search bar
+   - Task status badges
+   - Batch action controls
+
+2. **Task List View**:
+   ```
+   | Filename | Status | Created | Completed | Actions |
+   |----------|--------|---------|-----------|---------|
+   | doc1.pdf | ✅ Completed | 2025-11-14 10:00 | 2025-11-14 10:05 | [Download] [View] |
+   | doc2.pdf | 🔄 Processing | 2025-11-14 10:10 | - | [Cancel] |
+   | doc3.pdf | ❌ Failed | 2025-11-14 09:00 | - | [Retry] [View Error] |
+   ```
+
+3. **User Information Display**:
+   - Show user display name in header
+   - Show last login time
+   - Show task statistics (total, completed, failed)
+
 ## Impact
 
 ### Affected Capabilities
 - `authentication`: Complete replacement of authentication mechanism
 - `user-management`: Simplified to read-only user information from external API
 - `session-management`: Modified to handle external tokens
+- `task-management`: NEW - User-specific task isolation and history
+- `file-access-control`: NEW - User-based file access restrictions
 
 ### Affected Code
 - **Backend Authentication**:
@@ -100,13 +193,26 @@ By migrating to the external API authentication service at https://pj-auth-api.v
   - `backend/app/services/auth_service.py`: New service for external API integration
 
 - **Database Models**:
-  - `backend/app/models/user.py`: Update User model with new fields
-  - `backend/alembic/versions/`: New migration for schema changes
+  - `backend/app/models/user.py`: Complete redesign with new schema
+  - `backend/app/models/task.py`: NEW - Task model with user association
+  - `backend/app/models/task_file.py`: NEW - Task file model
+  - `backend/alembic/versions/`: Complete database recreation
+
+- **Task Management APIs** (NEW):
+  - `backend/app/api/v1/endpoints/tasks.py`: Task CRUD operations with user isolation
+  - `backend/app/api/v1/endpoints/task_history.py`: Historical query endpoints
+  - `backend/app/services/task_service.py`: Task business logic
+  - `backend/app/services/file_access_service.py`: User-based file access control
 
 - **Frontend**:
   - `frontend/src/services/authService.ts`: Update to handle new token format
   - `frontend/src/stores/authStore.ts`: Modify to store/display user info from API
-  - `frontend/src/components/Header.tsx`: Display `name` field instead of username
+  - `frontend/src/components/Header.tsx`: Display `name` field and user menu
+  - `frontend/src/pages/TaskHistory.tsx`: NEW - Task history page
+  - `frontend/src/components/TaskList.tsx`: NEW - Task list component with filters
+  - `frontend/src/components/TaskFilters.tsx`: NEW - Search and filter UI
+  - `frontend/src/stores/taskStore.ts`: NEW - Task state management
+  - `frontend/src/services/taskService.ts`: NEW - Task API client
 
 ### Dependencies
 - Add `httpx` or `aiohttp` for async HTTP requests to external API (already present)
@@ -117,8 +223,10 @@ By migrating to the external API authentication service at https://pj-auth-api.v
   - `EXTERNAL_AUTH_API_URL` = "https://pj-auth-api.vercel.app"
   - `EXTERNAL_AUTH_ENDPOINT` = "/api/auth/login"
   - `EXTERNAL_AUTH_TIMEOUT` = 30 (seconds)
-  - `USE_EXTERNAL_AUTH` = true (feature flag for gradual rollout)
   - `TOKEN_REFRESH_BUFFER` = 300 (refresh tokens 5 minutes before expiry)
+  - `TASK_RETENTION_DAYS` = 30 (auto-delete old tasks)
+  - `MAX_TASKS_PER_USER` = 1000 (limit per user)
+  - `ENABLE_TASK_HISTORY` = true (enable history feature)
 
 ### Security Considerations
 - HTTPS required for all authentication requests
@@ -127,21 +235,18 @@ By migrating to the external API authentication service at https://pj-auth-api.v
 - Log all authentication events for audit trail
 - Validate SSL certificates for external API calls
 - Handle network failures gracefully with appropriate error messages
+- **User Isolation**: Enforce user context in all database queries
+- **File Access Control**: Validate user ownership before file access
+- **API Security**: Add user_id validation in all task-related endpoints
 
-### Rollback Strategy
-- Keep existing authentication code with feature flag
-- Maintain password column in database (don't drop immediately)
-- Implement dual authentication mode during transition:
-  - If `USE_EXTERNAL_AUTH=true`: Use external API
-  - If `USE_EXTERNAL_AUTH=false`: Use local authentication
-- Provide migration script to sync existing users with external system
+### Migration Plan (Simplified - No Rollback Needed)
+1. **Phase 1**: Backup existing database (for reference only)
+2. **Phase 2**: Drop old tables and create new schema
+3. **Phase 3**: Deploy new authentication and task management system
+4. **Phase 4**: Test with initial users
+5. **Phase 5**: Full deployment
 
-### Migration Plan
-1. **Phase 1**: Implement external API authentication alongside existing system
-2. **Phase 2**: Test with subset of users (based on domain or user flag)
-3. **Phase 3**: Gradual rollout to all users
-4. **Phase 4**: Deprecate local authentication (keep code for emergency)
-5. **Phase 5**: Remove local authentication code (after stable period)
+Note: Since this is a test system with no production data to preserve, we can perform a clean migration without rollback concerns.
 
 ## Risks and Mitigations
 
diff --git a/openspec/changes/migrate-to-external-api-authentication/tasks.md b/openspec/changes/migrate-to-external-api-authentication/tasks.md
index 50fb123..c2d18de 100644
--- a/openspec/changes/migrate-to-external-api-authentication/tasks.md
+++ b/openspec/changes/migrate-to-external-api-authentication/tasks.md
@@ -1,32 +1,40 @@
 # Implementation Tasks
 
-## 1. Database Schema Updates
-- [ ] 1.1 Create database migration script
-  - Add `external_user_id` column (VARCHAR 255)
-  - Add `display_name` column (VARCHAR 255)
-  - Add `azure_email` column (VARCHAR 255)
-  - Add `last_token_refresh` column (DATETIME)
-  - Mark `hashed_password` as nullable (for gradual migration)
-- [ ] 1.2 Update User model
-  - Add new fields to SQLAlchemy model
-  - Update model relationships if needed
-  - Add migration version with Alembic
-- [ ] 1.3 Create user sync mechanism
-  - Script to map existing users to external IDs
-  - Handle users without external accounts
-  - Backup existing user data
+## 1. Database Schema Redesign
+- [ ] 1.1 Backup existing database (for reference)
+  - Export current schema and data
+  - Document any important data to preserve
+- [ ] 1.2 Drop old tables
+  - Remove existing users table
+  - Remove any related tables
+  - Clear database for fresh start
+- [ ] 1.3 Create new database schema
+  - Create new `users` table (email as primary identifier)
+  - Create `ocr_tasks` table with user association
+  - Create `task_files` table for file tracking
+  - Add proper indexes for performance
+- [ ] 1.4 Create SQLAlchemy models
+  - User model (simplified)
+  - Task model with user relationship
+  - TaskFile model with cascade delete
+- [ ] 1.5 Generate Alembic migration
+  - Create initial migration for new schema
+  - Test migration script
 
 ## 2. Configuration Management
 - [ ] 2.1 Update environment configuration
   - Add `EXTERNAL_AUTH_API_URL` to `.env.local`
   - Add `EXTERNAL_AUTH_ENDPOINT` configuration
   - Add `EXTERNAL_AUTH_TIMEOUT` setting
-  - Add `USE_EXTERNAL_AUTH` feature flag
   - Add `TOKEN_REFRESH_BUFFER` setting
+  - Add `TASK_RETENTION_DAYS` for auto-cleanup
+  - Add `MAX_TASKS_PER_USER` for limits
+  - Add `ENABLE_TASK_HISTORY` feature flag
 - [ ] 2.2 Update Settings class
   - Add external auth settings to `backend/app/core/config.py`
+  - Add task management settings
   - Add validation for new configuration values
-  - Implement feature flag logic
+  - Remove old authentication settings
 
 ## 3. External API Integration Service
 - [ ] 3.1 Create auth API client
@@ -99,82 +107,166 @@
   - Implement retry UI for failures
   - Add loading states
 
-## 7. Testing
-- [ ] 7.1 Unit tests
+## 7. Task Management System (NEW)
+- [ ] 7.1 Create task management backend
+  - Implement `backend/app/models/task.py`
+  - Implement `backend/app/models/task_file.py`
+  - Create `backend/app/services/task_service.py`
+  - Add task CRUD operations with user isolation
+- [ ] 7.2 Implement task APIs
+  - Create `backend/app/api/v1/endpoints/tasks.py`
+  - GET /tasks (list user's tasks with pagination)
+  - GET /tasks/{id} (get specific task)
+  - DELETE /tasks/{id} (delete task)
+  - POST /tasks/{id}/retry (retry failed task)
+- [ ] 7.3 Create task history endpoints
+  - Create `backend/app/api/v1/endpoints/task_history.py`
+  - GET /history (query with filters)
+  - GET /history/stats (user statistics)
+  - POST /history/export (export history)
+- [ ] 7.4 Implement file access control
+  - Create `backend/app/services/file_access_service.py`
+  - Validate user ownership before file access
+  - Restrict download to user's own files
+  - Add audit logging for file access
+- [ ] 7.5 Update OCR service integration
+  - Link OCR tasks to user accounts
+  - Save task records in database
+  - Update task status during processing
+  - Store result file paths
+
+## 8. Frontend Task Management UI (NEW)
+- [ ] 8.1 Create task history page
+  - Implement `frontend/src/pages/TaskHistory.tsx`
+  - Display task list with status indicators
+  - Add pagination controls
+  - Show task details modal
+- [ ] 8.2 Build task list component
+  - Implement `frontend/src/components/TaskList.tsx`
+  - Display task table with columns
+  - Add sorting capabilities
+  - Implement action buttons
+- [ ] 8.3 Create filter components
+  - Implement `frontend/src/components/TaskFilters.tsx`
+  - Date range picker
+  - Status filter dropdown
+  - Search by filename
+  - Clear filters button
+- [ ] 8.4 Add task management store
+  - Implement `frontend/src/stores/taskStore.ts`
+  - Manage task list state
+  - Handle filter state
+  - Cache task data
+- [ ] 8.5 Create task service client
+  - Implement `frontend/src/services/taskService.ts`
+  - API methods for task operations
+  - Handle pagination
+  - Implement retry logic
+- [ ] 8.6 Update navigation
+  - Add "Task History" menu item
+  - Update router configuration
+  - Add task count badge
+  - Implement user menu with stats
+
+## 9. User Isolation and Security
+- [ ] 9.1 Implement user context middleware
+  - Create middleware to inject user context
+  - Validate user in all requests
+  - Add user_id to logging context
+- [ ] 9.2 Database query isolation
+  - Add user_id filter to all task queries
+  - Prevent cross-user data access
+  - Implement row-level security
+- [ ] 9.3 File system isolation
+  - Organize files by user directory
+  - Validate file paths before access
+  - Implement cleanup for deleted users
+- [ ] 9.4 API authorization
+  - Add @require_user decorator
+  - Validate ownership in endpoints
+  - Return 403 for unauthorized access
+
+## 10. Testing
+- [ ] 10.1 Unit tests
   - Test external auth service
   - Test token validation
-  - Test user information mapping
-  - Test error scenarios
-- [ ] 7.2 Integration tests
+  - Test task isolation logic
+  - Test file access control
+- [ ] 10.2 Integration tests
   - Test full authentication flow
-  - Test token refresh mechanism
-  - Test fallback scenarios
-  - Test feature flag switching
-- [ ] 7.3 Load testing
+  - Test task management flow
+  - Test user isolation between accounts
+  - Test file download restrictions
+- [ ] 10.3 Load testing
   - Test external API response times
-  - Test system under high authentication load
-  - Measure impact on performance
-- [ ] 7.4 Security testing
+  - Test system with many concurrent users
+  - Test large task history queries
+  - Measure database query performance
+- [ ] 10.4 Security testing
   - Test token security
-  - Verify HTTPS enforcement
-  - Test rate limiting
-  - Validate error message security
+  - Verify user isolation
+  - Test unauthorized access attempts
+  - Validate SQL injection prevention
 
-## 8. Migration Execution
-- [ ] 8.1 Pre-migration preparation
-  - Backup database
-  - Document rollback procedure
-  - Prepare user communication
+## 11. Migration Execution (Simplified)
+- [ ] 11.1 Pre-migration preparation
+  - Backup existing database (reference only)
+  - Prepare deployment package
   - Set up monitoring
-- [ ] 8.2 Staged rollout
-  - Enable for test users first
-  - Monitor for issues
-  - Gradually increase user percentage
-  - Collect feedback
-- [ ] 8.3 Post-migration validation
-  - Verify all users can login
-  - Check audit logs
-  - Monitor error rates
-  - Validate performance metrics
+- [ ] 11.2 Execute migration
+  - Drop old database tables
+  - Create new schema
+  - Deploy new code
+  - Verify system startup
+- [ ] 11.3 Post-migration validation
+  - Test authentication with real users
+  - Verify task isolation works
+  - Check task history functionality
+  - Validate file access controls
 
-## 9. Documentation
-- [ ] 9.1 Technical documentation
-  - Update API documentation
+## 12. Documentation
+- [ ] 12.1 Technical documentation
+  - Update API documentation with new endpoints
   - Document authentication flow
-  - Update deployment guide
+  - Document task management APIs
   - Create troubleshooting guide
-- [ ] 9.2 User documentation
+- [ ] 12.2 User documentation
   - Update login instructions
-  - Document new features
-  - Create FAQ for common issues
-- [ ] 9.3 Operations documentation
-  - Document monitoring points
-  - Create runbook for issues
-  - Document rollback procedure
+  - Document task history features
+  - Explain user isolation
+  - Create user guide for new UI
+- [ ] 12.3 Developer documentation
+  - Document database schema
+  - Explain security model
+  - Provide integration examples
 
-## 10. Monitoring and Observability
-- [ ] 10.1 Add monitoring metrics
+## 13. Monitoring and Observability
+- [ ] 13.1 Add monitoring metrics
   - Authentication success/failure rates
-  - External API response times
-  - Token refresh success rate
-  - Error rate monitoring
-- [ ] 10.2 Implement logging
+  - Task creation/completion rates
+  - User activity metrics
+  - File storage usage
+- [ ] 13.2 Implement logging
   - Log all authentication attempts
-  - Log external API calls
-  - Log token operations
+  - Log task operations
+  - Log file access attempts
   - Structured logging for analysis
-- [ ] 10.3 Create alerts
-  - Alert on high failure rates
-  - Alert on external API unavailability
-  - Alert on token refresh failures
-  - Alert on unusual patterns
+- [ ] 13.3 Create alerts
+  - Alert on authentication failures
+  - Alert on high error rates
+  - Alert on storage issues
+  - Alert on performance degradation
 
-## 11. Cleanup (Post-Stabilization)
-- [ ] 11.1 Remove legacy code
-  - Remove local authentication code (after stable period)
-  - Remove unused database columns
-  - Clean up configuration
-- [ ] 11.2 Optimize performance
-  - Implement caching where appropriate
-  - Optimize database queries
-  - Review and optimize API calls
\ No newline at end of file
+## 14. Performance Optimization (Post-Launch)
+- [ ] 14.1 Database optimization
+  - Analyze query patterns
+  - Add missing indexes
+  - Optimize slow queries
+- [ ] 14.2 Caching implementation
+  - Cache user information
+  - Cache task lists
+  - Implement Redis if needed
+- [ ] 14.3 File management
+  - Implement automatic cleanup
+  - Optimize storage structure
+  - Add compression if needed
\ No newline at end of file