sbroenne · sbroenne · Dec 1, 2025 · Dec 1, 2025 · Dec 1, 2025 · Dec 1, 2025
diff --git a/.github/workflows/release-mcp-server.yml b/.github/workflows/release-mcp-server.yml
@@ -96,26 +96,14 @@ jobs:
         dotnet restore src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
         dotnet restore src/ExcelMcp.CLI/ExcelMcp.CLI.csproj
 
-    - name: Inject Application Insights Connection String
-      run: |
-        $telemetryFile = "src/ExcelMcp.McpServer/Telemetry/ExcelMcpTelemetry.cs"
-        $connectionString = "${{ secrets.APPINSIGHTS_CONNECTION_STRING }}"
-
-        if ([string]::IsNullOrWhiteSpace($connectionString)) {
-          Write-Output "⚠️ APPINSIGHTS_CONNECTION_STRING secret not configured - telemetry will be disabled"
-        } else {
-          Write-Output "Injecting Application Insights connection string..."
-          $content = Get-Content $telemetryFile -Raw
-          $content = $content -replace '__APPINSIGHTS_CONNECTION_STRING__', $connectionString
-          Set-Content $telemetryFile $content
-          Write-Output "✅ Telemetry connection string injected"
-        }
-      shell: pwsh
-
     - name: Build MCP Server & CLI
       run: |
         dotnet build src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj --configuration Release --no-restore
         dotnet build src/ExcelMcp.CLI/ExcelMcp.CLI.csproj --configuration Release --no-restore
+      env:
+        # Application Insights connection string is embedded at build time by MSBuild
+        # See ExcelMcp.McpServer.csproj for the GenerateTelemetryConfig target
+        APPINSIGHTS_CONNECTION_STRING: ${{ secrets.APPINSIGHTS_CONNECTION_STRING }}
 
     - name: Skip Tests (require Excel)
       run: |

diff --git a/.github/workflows/release-vscode-extension.yml b/.github/workflows/release-vscode-extension.yml
@@ -75,28 +75,19 @@ jobs:
         cd vscode-extension
         npm install
 
-    - name: Inject Application Insights Connection String
-      run: |
-        $telemetryFile = "src/ExcelMcp.McpServer/Telemetry/ExcelMcpTelemetry.cs"
-        $connectionString = "${{ secrets.APPINSIGHTS_CONNECTION_STRING }}"
-
-        if ([string]::IsNullOrWhiteSpace($connectionString)) {
-          Write-Output "⚠️ APPINSIGHTS_CONNECTION_STRING secret not configured - telemetry will be disabled"
-        } else {
-          Write-Output "Injecting Application Insights connection string..."
-          $content = Get-Content $telemetryFile -Raw
-          $content = $content -replace '__APPINSIGHTS_CONNECTION_STRING__', $connectionString
-          Set-Content $telemetryFile $content
-          Write-Output "✅ Telemetry connection string injected"
-        }
-      shell: pwsh
-
     - name: Build and Package Extension
       run: |
         cd vscode-extension
         # Run the package script which does: build:mcp-server + vsce package
         npm run package
+      env:
+        # Application Insights connection string is embedded at build time by MSBuild
+        # See ExcelMcp.McpServer.csproj for the GenerateTelemetryConfig target
+        APPINSIGHTS_CONNECTION_STRING: ${{ secrets.APPINSIGHTS_CONNECTION_STRING }}
 
+    - name: Prepare VSIX
+      run: |
+        cd vscode-extension
         $version = "${{ env.PACKAGE_VERSION }}"
 
         # vsce creates filename based on package.json name (excel-mcp)

diff --git a/.gitignore b/.gitignore
@@ -226,3 +226,11 @@ gh-pages/_site/*
 
 codeql-db/*
 infrastructure/azure/appinsights.secrets.local
+
+# Local environment files (secrets, connection strings)
+.env
+.env.local
+.env.*.local
+
+# Local MSBuild properties (secrets, connection strings)
+Directory.Build.props.user
diff --git a/Directory.Build.props b/Directory.Build.props
@@ -49,4 +49,7 @@
   </PropertyGroup>
 
 
+  <!-- Import user-specific properties (gitignored, for local secrets) -->
+  <Import Project="Directory.Build.props.user" Condition="Exists('Directory.Build.props.user')" />
+
 </Project>
diff --git a/Directory.Build.props.user.template b/Directory.Build.props.user.template
@@ -0,0 +1,17 @@
+<!--
+  Local developer settings (COPY to Directory.Build.props.user)
+
+  This file is a template. To use:
+  1. Copy this file to Directory.Build.props.user
+  2. Fill in your actual values
+  3. Directory.Build.props.user is gitignored and won't be committed
+
+  The values here are picked up by MSBuild at build time and embedded into the compiled assembly.
+-->
+<Project>
+  <PropertyGroup>
+    <!-- Application Insights connection string for telemetry -->
+    <!-- Get from Azure Portal: Application Insights > Overview > Connection String -->
+    <AppInsightsConnectionString>YOUR_CONNECTION_STRING_HERE</AppInsightsConnectionString>
+  </PropertyGroup>
+</Project>
diff --git a/Directory.Packages.props b/Directory.Packages.props
@@ -13,7 +13,10 @@
     <PackageVersion Include="Microsoft.Extensions.Hosting" Version="9.0.10" />
     <PackageVersion Include="Microsoft.Extensions.Logging" Version="9.0.10" />
     <PackageVersion Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.0" />
-    <!-- Application Insights SDK for telemetry (Users, Sessions, Funnels, User Flows) -->
+    <!-- Application Insights Worker Service SDK for telemetry (Users, Sessions, Funnels, User Flows) -->
+    <!-- Worker Service SDK provides proper DI integration, auto-collection modules, and host lifetime awareness -->
+    <PackageVersion Include="Microsoft.ApplicationInsights.WorkerService" Version="2.23.0" />
+    <!-- Base SDK needed for tests that directly use TelemetryClient -->
     <PackageVersion Include="Microsoft.ApplicationInsights" Version="2.23.0" />
     <PackageVersion Include="Microsoft.Extensions.Resilience" Version="10.0.0" />
     <PackageVersion Include="Microsoft.Extensions.Configuration" Version="9.0.10" />
@@ -37,4 +40,4 @@
     <PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.5" />
     <PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="10.0.100" />
   </ItemGroup>
-</Project>
+</Project>
diff --git a/README.md b/README.md
@@ -140,3 +140,4 @@ This means you get:
 ### SEO & Discovery
 
 `Excel Automation` • `Automate Excel with AI` • `MCP Server` • `Model Context Protocol` • `GitHub Copilot Excel` • `AI Excel Assistant` • `Power Query Automation` • `Power Query M Code` • `Power Pivot Automation` • `DAX Measures` • `DAX Automation` • `Data Model Automation` • `PivotTable Automation` • `VBA Automation` • `Excel Tables Automation` • `Excel AI Integration` • `COM Interop` • `Windows Excel Automation` • `Excel Development Tools` • `Excel Productivity` • `Excel Scripting` • `Conversational Excel` • `Natural Language Excel`
+# test
diff --git a/docs/DEVELOPMENT.md b/docs/DEVELOPMENT.md
@@ -373,13 +373,23 @@ dotnet build -c Release
 
 ## 📊 **Application Insights / Telemetry Setup**
 
-ExcelMcp uses Azure Application Insights for anonymous usage telemetry and crash reporting. Telemetry is **opt-out** (enabled by default in release builds).
+ExcelMcp uses Azure Application Insights (Classic SDK with WorkerService integration) for anonymous usage telemetry and crash reporting. Telemetry is **opt-out** (enabled by default in release builds).
+
+### **How It Works**
+
+The Application Insights connection string is **embedded at build time** via MSBuild - there is no runtime environment variable lookup.
+
+**Build-time flow:**
+1. MSBuild reads `AppInsightsConnectionString` property (from `Directory.Build.props.user` or env var)
+2. Generates `TelemetryConfig.g.cs` with the connection string as a `const string`
+3. Compiled assembly contains the embedded connection string
 
 ### **What is Tracked**
 
 - **Tool invocations**: Tool name, action, duration (ms), success/failure
 - **Unhandled exceptions**: Exception type and redacted stack trace
-- **Session ID**: Random GUID per process (no user identification)
+- **User ID**: SHA256 hash of machine identity (anonymous, 16 chars)
+- **Session ID**: Random GUID per process (8 chars)
 
 ### **What is NOT Tracked**
 
@@ -396,6 +406,30 @@ All telemetry passes through `SensitiveDataRedactingProcessor` which removes:
 - Connection string secrets (`Password=...` → `[REDACTED_CREDENTIAL]`)
 - Email addresses → `[REDACTED_EMAIL]`
 
+### **Local Development with Telemetry**
+
+To enable telemetry in local builds:
+
+```powershell
+# 1. Copy the template file
+Copy-Item "Directory.Build.props.user.template" "Directory.Build.props.user"
+
+# 2. Edit Directory.Build.props.user and add your connection string
+# <AppInsightsConnectionString>InstrumentationKey=xxx;IngestionEndpoint=...</AppInsightsConnectionString>
+
+# 3. Build - connection string is embedded at compile time
+dotnet build src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
+
+# 4. Run - telemetry is automatically sent to Azure
+dotnet run --project src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
+```
+
+**Note:** `Directory.Build.props.user` is gitignored - your connection string won't be committed.
+
+### **Local Development without Telemetry**
+
+If you don't create `Directory.Build.props.user`, builds will have an empty connection string and telemetry will be disabled. This is the default for local development.
+
 ### **Azure Resources Setup (Maintainers Only)**
 
 To deploy the Application Insights infrastructure:
@@ -419,106 +453,37 @@ After deploying Azure resources:
 2. Add new secret: `APPINSIGHTS_CONNECTION_STRING`
 3. Paste the connection string from deployment output
 
-The release workflow automatically injects this at build time.
-
-### **Local Development**
-
-During local development, telemetry is **disabled by default** because the placeholder connection string is not replaced. This is intentional - no telemetry data is sent from dev builds.
-
-#### **Debug Mode: Console Output**
-
-To test telemetry locally without Azure, enable debug mode which logs to stderr:
-
-```powershell
-# Enable debug telemetry (logs to console instead of Azure)
-$env:EXCELMCP_DEBUG_TELEMETRY = "true"
-
-# Build and run the MCP server
-dotnet build src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
-dotnet run --project src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
-
-# You'll see telemetry output like:
-# [Telemetry] Debug mode enabled - logging to stderr
-# Activity.TraceId: abc123...
-# Activity.DisplayName: ToolInvocation
-# Activity.Tags:
-#     tool.name: excel_file
-#     tool.action: list
-#     tool.duration_ms: 42
-#     tool.success: true
-```
-
-#### **Testing with Real Azure Resources**
-
-To test with actual Application Insights:
-
-```powershell
-# 1. Deploy Azure resources
-.\infrastructure\azure\deploy-appinsights.ps1 -SubscriptionId "<your-sub-id>"
-
-# 2. Temporarily inject connection string (DON'T COMMIT!)
-$connStr = "InstrumentationKey=xxx;IngestionEndpoint=https://..."
-(Get-Content "src/ExcelMcp.McpServer/Telemetry/ExcelMcpTelemetry.cs") -replace `
-    '__APPINSIGHTS_CONNECTION_STRING__', $connStr | `
-    Set-Content "src/ExcelMcp.McpServer/Telemetry/ExcelMcpTelemetry.cs"
-
-# 3. Build and run
-dotnet build src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
-dotnet run --project src/ExcelMcp.McpServer/ExcelMcp.McpServer.csproj
-
-# 4. Check Azure Portal → Application Insights → Transaction search
-
-# 5. IMPORTANT: Revert the file (don't commit connection string!)
-git checkout src/ExcelMcp.McpServer/Telemetry/ExcelMcpTelemetry.cs
-```
-
-To verify telemetry state:
-```csharp
-// ExcelMcpTelemetry.IsEnabled returns false when:
-// - Connection string is placeholder "__APPINSIGHTS_CONNECTION_STRING__"
-// - User has opted out via EXCELMCP_TELEMETRY_OPTOUT=true
-
-// ExcelMcpTelemetry.IsEnabled returns true when:
-// - EXCELMCP_DEBUG_TELEMETRY=true (console output mode)
-// - Connection string is real (injected at build time)
-```
-
-### **User Opt-Out**
-
-Users can disable telemetry by setting an environment variable:
-
-```powershell
-# Windows
-$env:EXCELMCP_TELEMETRY_OPTOUT = "true"
-
-# Or permanently via System Properties → Environment Variables
-```
+The release workflow sets this as an environment variable, and MSBuild embeds it at build time.
 
 ### **Telemetry Architecture**
 
-```
-MCP Tool Invocation
-    │
-    ▼
-ExcelToolsBase.ExecuteToolAction()
-    │ (tracks: tool, action, duration, success)
-    ▼
-ExcelMcpTelemetry.TrackToolInvocation()
-    │
-    ▼
-SensitiveDataRedactingProcessor
-    │ (removes: paths, credentials, emails)
-    ▼
-Azure Monitor Exporter → Application Insights
+```text
+Build Time:
+  MSBuild → reads AppInsightsConnectionString → generates TelemetryConfig.g.cs
+
+Runtime:
+  MCP Tool Invocation
+      │
+      ▼
+  ExcelMcpTelemetry.TrackToolInvocation()
+      │ (tracks: tool, action, duration, success)
+      ▼
+  SensitiveDataRedactingProcessor
+      │ (removes: paths, credentials, emails)
+      ▼
+  TelemetryClient → Application Insights
 ```
 
 ### **Files Overview**
 
 | File | Purpose |
 |------|---------|
-| `Telemetry/ExcelMcpTelemetry.cs` | Static helper for tracking |
+| `Telemetry/ExcelMcpTelemetry.cs` | Static helper for tracking events |
+| `Telemetry/ExcelMcpTelemetryInitializer.cs` | Sets User.Id and Session.Id on telemetry |
 | `Telemetry/SensitiveDataRedactingProcessor.cs` | Redacts PII before transmission |
-| `Program.cs` | OpenTelemetry configuration |
+| `Program.cs` | Application Insights WorkerService configuration |
+| `ExcelMcp.McpServer.csproj` | MSBuild target that generates TelemetryConfig.g.cs |
+| `Directory.Build.props.user.template` | Template for local dev connection string |
 | `infrastructure/azure/appinsights.bicep` | Azure resource definitions |
 | `infrastructure/azure/deploy-appinsights.ps1` | Deployment script |
Original file line number	Diff line number	Diff line change
Expand Up		@@ -140,3 +140,4 @@ This means you get:
		### SEO & Discovery

		`Excel Automation` • `Automate Excel with AI` • `MCP Server` • `Model Context Protocol` • `GitHub Copilot Excel` • `AI Excel Assistant` • `Power Query Automation` • `Power Query M Code` • `Power Pivot Automation` • `DAX Measures` • `DAX Automation` • `Data Model Automation` • `PivotTable Automation` • `VBA Automation` • `Excel Tables Automation` • `Excel AI Integration` • `COM Interop` • `Windows Excel Automation` • `Excel Development Tools` • `Excel Productivity` • `Excel Scripting` • `Conversational Excel` • `Natural Language Excel`
		# test