use DefaultAzureCredential instead of AzureCliCredential (#3860)

dotnet/samples/GettingStarted/AgentWithMemory/AgentWithMemory_Step01_ChatHistoryMemory/Program.cs

@@ -20,7 +20,10 @@ var embeddingDeploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_E
 // Replace this with a vector store implementation of your choice that can persist the chat history long term.
 VectorStore vectorStore = new InMemoryVectorStore(new InMemoryVectorStoreOptions()
 {
-    EmbeddingGenerator = new AzureOpenAIClient(new Uri(endpoint), new AzureCliCredential())
+    // WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+    // In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
+    // latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
+    EmbeddingGenerator = new AzureOpenAIClient(new Uri(endpoint), new DefaultAzureCredential())
         .GetEmbeddingClient(embeddingDeploymentName)
         .AsIEmbeddingGenerator()
 });
@@ -28,7 +31,7 @@ VectorStore vectorStore = new InMemoryVectorStore(new InMemoryVectorStoreOptions
 // Create the agent and add the ChatHistoryMemoryProvider to store chat messages in the vector store.
 AIAgent agent = new AzureOpenAIClient(
     new Uri(endpoint),
-    new AzureCliCredential())
+    new DefaultAzureCredential())
     .GetChatClient(deploymentName)
     .AsAIAgent(new ChatClientAgentOptions
     {

dotnet/samples/GettingStarted/AgentWithMemory/AgentWithMemory_Step02_MemoryUsingMem0/Program.cs

@@ -24,9 +24,12 @@ using HttpClient mem0HttpClient = new();
 mem0HttpClient.BaseAddress = new Uri(mem0ServiceUri);
 mem0HttpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Token", mem0ApiKey);
 
+// WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+// In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
+// latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
 AIAgent agent = new AzureOpenAIClient(
     new Uri(endpoint),
-    new AzureCliCredential())
+    new DefaultAzureCredential())
     .GetChatClient(deploymentName)
     .AsAIAgent(new ChatClientAgentOptions()
     {

dotnet/samples/GettingStarted/AgentWithMemory/AgentWithMemory_Step03_CustomMemory/Program.cs

@@ -18,9 +18,12 @@ using SampleApp;
 var endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
 var deploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOYMENT_NAME") ?? "gpt-4o-mini";
 
+// WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+// In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
+// latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
 ChatClient chatClient = new AzureOpenAIClient(
     new Uri(endpoint),
-    new AzureCliCredential())
+    new DefaultAzureCredential())
     .GetChatClient(deploymentName);
 
 // Create the agent and provide a factory to add our custom memory component to