Add Azure tenant ID to OpenAI client configuration and usage

Co-authored-by: diberry <41597107+diberry@users.noreply.github.com>

Author: Copilot

ai/vector-search-dotnet/Models/Configuration.cs

@@ -14,6 +14,7 @@ public class AzureOpenAIConfiguration
     public string EmbeddingModel { get; set; } = string.Empty;
     public string ApiVersion { get; set; } = string.Empty;
     public string Endpoint { get; set; } = string.Empty;
+    public string TenantId { get; set; } = string.Empty;
     // Note: API Key removed - using Microsoft Entra ID authentication via DefaultAzureCredential
 }
 

ai/vector-search-dotnet/Services/EmbeddingService.cs

@@ -24,9 +24,13 @@ public EmbeddingService(
 
         try
         {
+            var credential = new DefaultAzureCredential(new DefaultAzureCredentialOptions
+            {
+                TenantId = _config.AzureOpenAI.TenantId
+            });
             _openAIClient = new AzureOpenAIClient(
                 new Uri(_config.AzureOpenAI.Endpoint),
-                new DefaultAzureCredential());
+                credential);
         }
         catch (Exception ex)
         {

ai/vector-search-dotnet/Services/VectorSearchService.cs

@@ -28,7 +28,11 @@ public VectorSearchService(ILogger<VectorSearchService> logger, MongoDbService m
         _config = config;
 
         // Initialize Azure OpenAI client with passwordless authentication
-        _openAIClient = new AzureOpenAIClient(new Uri(_config.AzureOpenAI.Endpoint), new DefaultAzureCredential());
+        var credential = new DefaultAzureCredential(new DefaultAzureCredentialOptions
+        {
+            TenantId = _config.AzureOpenAI.TenantId
+        });
+        _openAIClient = new AzureOpenAIClient(new Uri(_config.AzureOpenAI.Endpoint), credential);
     }
 
     /// <summary>

ai/vector-search-dotnet/appsettings.json

@@ -1,5 +1,6 @@
 {
   "AzureOpenAI": {
+    "TenantId": "<your-tenant-id>",
     "EmbeddingModel": "text-embedding-3-small",
     "ApiVersion": "2023-05-15",
     "Endpoint": "https://<your-openai-service-name>.openai.azure.com/"