Enable MCP Notification System

[avrabe]

Epic: MCP Integration

Priority: Critical
Story Points: 5
Phase: 1

Problem

The MCP client has notification infrastructure (sendNotification(), handleNotification(), listener management) but it's not connected to the UI for bidirectional server communication.

Solution

Enable the notification system by connecting it to UI state management and server events.

Implementation Details

Ready-to-use code in src/mcp/client.ts:

• sendNotification() - Send notifications to server (lines 195-232)
• handleNotification() - Process incoming notifications (lines 489-501)
• addNotificationListener() - Register notification handlers (lines 468-473)
• removeNotificationListener() - Cleanup listeners (lines 475-483)

Tasks

• Connect handleNotification() to UI state management
• Use sendNotification() for user actions that need server awareness
• Add notification listeners for diagram events
• Implement bidirectional diagram synchronization

Acceptance Criteria

• UI can send notifications to server for user actions
• Server notifications update UI state automatically
• Multiple notification types are supported
• Notification listeners can be added/removed dynamically
• Error handling prevents notification failures from breaking UI

Technical Notes

• Uses JSON-RPC 2.0 notification format (no response expected)
• Session ID included in headers for authentication
• Supports both one-way and bidirectional communication
• Error recovery maintains notification reliability

Files:

• src/mcp/client.ts:195-232 (sendNotification)
• src/mcp/client.ts:468-501 (notification handling)

[avrabe]

✅ MCP Notification System Implementation Complete

The comprehensive bidirectional notification system has been successfully implemented and integrated across all architectural layers.

Completed Features

Core Infrastructure

• Made sendNotification() method public in McpClient for external access
• Added notification methods to McpService for service layer abstraction
• Connected notification listeners to DiagramService for domain-specific handling
• Integrated notifications into user actions throughout AppController

Notification Types Implemented

• diagram-opened: Sent when user opens/loads a diagram
• diagram-modified: Sent when user creates nodes, edges, or modifies diagrams
• elements-selected: Sent when user selects diagram elements
• validation-requested: Sent when user requests diagram validation

Bidirectional Communication

• Client → Server: User action notifications with timestamp and userId
• Server → Client: Diagram change notifications with automatic UI updates
• Error Handling: Comprehensive logging and graceful error recovery
• Integration: Automatic setup during service initialization

Technical Implementation

The notification system is fully integrated across the complete architecture:

McpClient.sendNotification() → McpService → DiagramService → AppController

All notification methods include proper error handling and are ready for production use.

Testing Results

• ✅ sendNotification() accessible from all service layers
• ✅ Notification listeners registered during initialization
• ✅ User actions trigger appropriate notifications
• ✅ Server notifications handled with UI updates

Implementation completed in PR #41