MCP Composable Integration - Complete Implementation

Overview

Successfully refactored the MCP setup functionality to use the centralized useMcpSetup.js composable, eliminating inline code duplication and adding comprehensive error handling.

Files Modified

1. web/src/composables/useMcpSetup.js (563 lines)

Enhanced with robust error handling for all export functions.

Changes:

• downloadFile() function:

  • Added support for both string and Blob content
  • Implemented try-catch error handling
  • Improved error messages with context

• downloadAllMcpFiles() function:

  • Added parameter validation (mcpConfig, agentName)
  • Added configuration property validation
  • Added JSZip import error handling
  • Comprehensive error logging and reporting
  • Returns proper error state to caller

• copyMcpFilesToProject() function:

  • Added parameter validation
  • Added response validation before JSON parsing
  • Checks Content-Type header before calling .json()
  • Handles missing or empty responses gracefully
  • Returns fallback file list on success even if response is empty

Key Error Handling Improvements:

// Check response exists
if (!response) {
  throw new Error('No response from server')
}

// Check content type before parsing JSON
const contentType = response.headers.get('content-type')
if (contentType && contentType.includes('application/json')) {
  result = await response.json()
}

2. web/src/views/ProjectDetail.vue (1413 lines)

Updated all event handlers to properly use composable functions with error handling.

Changes:

• downloadMcpFile() handler:

  • Wrapped in try-catch block
  • Displays user-friendly error alerts
  • Logs errors to console for debugging

• handleDownloadAllMcpFiles() handler:

  • Wrapped in try-catch block
  • Properly awaits composable function
  • Displays error messages to users

Example Handler:

const handleDownloadAllMcpFiles = async () => {
  try {
    await downloadAllMcpFiles(mcpConfig.value, mcpSetupAgent.value.name)
  } catch (error) {
    console.error('Failed to download MCP files:', error)
    alert(`Failed to download MCP files: ${error.message}`)
  }
}

Problem Resolution

Issue: "Cannot read properties of undefined (reading 'json')"

Root Cause: The copyMcpFilesToProject() function was attempting to call .json() on a response without checking if:

1. The response object was defined
2. The response had a JSON content-type

Solution:

• Added null/undefined checks for response object
• Check Content-Type header before parsing JSON
• Provide fallback values on successful requests even if response body is empty
• Improved error messages with response text context

Issue: Blob Handling in Download Function

Root Cause: The original downloadFile() function only handled strings, failing when JSZip returned a Blob object.

Solution:

• Added type checking for Blob vs string content
• Handle both types appropriately
• Added error wrapping for debugging

Integration Status

✅ Composable Usage

All MCP configuration is now centralized in useMcpSetup.js:

• mcpSettingsJson - VS Code environment variables
• mcpCopilotInstructions - Agent identity instructions
• mcpPowerShellScript - PowerShell helper functions
• mcpBashScript - Bash helper functions
• mcpVSCodeJson - VS Code MCP configuration
• mcpVS2026Json - Visual Studio 2026 full configuration
• mcpConfig - Bundle of all configurations
• downloadFile - File download utility
• downloadAllMcpFiles - ZIP creation function (with error handling)
• copyMcpFilesToProject - Direct project file creation (with error handling)

✅ Event Flow

1. User clicks "Download All" button in McpSetupModal
2. Modal emits @download-all event
3. ProjectDetail.vue catches event in handleDownloadAllMcpFiles()
4. Handler calls composable's downloadAllMcpFiles() function
5. Function validates input, creates ZIP, handles errors gracefully

✅ Error Handling

All error paths now:

• Log to console for developer debugging
• Display user-friendly alerts
• Prevent silent failures
• Provide actionable error messages

Testing Checklist

• Download individual MCP files (settings, mcp, copilot, powershell, bash)
• Download all MCP files as ZIP
• Copy MCP files directly to project (when backend endpoint implemented)
• Test error handling with invalid inputs
• Test error handling with network failures
• Verify ZIP contains all 6 files + README
• Test in VS Code with extracted files
• Test in Visual Studio 2026 with .mcp.json

Next Steps

Backend Implementation

• Implement POST /api/projects/{id}/mcp-files endpoint
• Accept file dictionary from request body
• Create files in project directory
• Return success response with file list

UI Enhancements

• Add loading states during download
• Add success/error toast notifications
• Add progress indicator for ZIP generation
• Add "Apply Configuration" button with loading state

Testing

• Test all download scenarios
• Test error scenarios
• Validate ZIP contents
• Test IDE integration (VS Code, VS 2026)

Code Quality Metrics

• Error Handling: Comprehensive try-catch blocks on all async operations
• Validation: Input parameter validation on all functions
• Logging: Console logging for debugging and error tracking
• User Feedback: Alert notifications for user-facing errors
• Type Safety: JSDoc comments on all exported functions
• Backward Compatibility: No breaking changes to existing code

Deployment Notes

This change is fully backward compatible:

• No API contract changes
• No database migrations required
• No configuration changes needed
• Can be deployed independently

The implementation follows Vue 3 Composition API best practices and the project's coding guidelines as specified in vue.instructions.md.