Allow case-insensitive agents and clients resolution

Configuration-driven sections can change case when a subsequent provider overrides a section value but uses a different casing (since config is inherently case-insensitive). This means we may end up with a client ID with an unexpected casing at run-time.

In order to solve this, we register both clients and agents using an alternative ServiceKey object which performs a comparer-aware comparison (defaults to ordinal ignore case).

Users would need to look for this alternative key explicitly, since we don't want to pollute the container with additional string-only registrations. But to improve discoverability of this case-insensitive lookup, we provide GetChatClient and GetAIAgent extension methods for IServiceProvider.

Author: kzu

AI.slnx

@@ -4,9 +4,13 @@
     <Platform Name="x64" />
     <Platform Name="x86" />
   </Configurations>
+  <Folder Name="/Sample/">
+    <Project Path="sample/Aspire/Aspire.csproj" Id="6166be22-a13f-4074-91a9-b0f3b3a6c4fe" />
+    <Project Path="sample/Client/Client.csproj" />
+    <Project Path="sample/Server/Server.csproj" Id="34619937-085f-453d-bc12-9ab2d4abccb7" />
+  </Folder>
   <Project Path="src/Agents/Agents.csproj" Id="90827430-b415-47d6-aac9-2dbe4911b348" />
   <Project Path="src/Extensions.CodeAnalysis/Extensions.CodeAnalysis.csproj" />
   <Project Path="src/Extensions/Extensions.csproj" />
-  <Project Path="src/SampleChat/SampleChat.csproj" Id="63ca9077-db60-473a-813d-d3bb5befdf35" />
   <Project Path="src/Tests/Tests.csproj" />
 </Solution>

src/Agents/ConfigurableAIAgent.cs

@@ -91,7 +91,8 @@ public override IAsyncEnumerable<AgentRunResponseUpdate> RunStreamingAsync(IEnum
 
         var client = services.GetKeyedService<IChatClient>(options?.Client
             ?? throw new InvalidOperationException($"A client must be specified for agent '{name}' in configuration section '{section}'."))
-            ?? throw new InvalidOperationException($"Specified chat client '{options?.Client}' for agent '{name}' is not registered.");
+            ?? services.GetKeyedService<IChatClient>(new ServiceKey(options!.Client))
+            ?? throw new InvalidOperationException($"Specified chat client '{options!.Client}' for agent '{name}' is not registered.");
 
         var provider = client.GetService<ChatClientMetadata>()?.ProviderName;
         ChatOptions? chat = provider == "xai"

src/Agents/AddAIAgentsExtensions.cs …c/Agents/ConfigurableAgentsExtensions.cssrc/Agents/AddAIAgentsExtensions.cs renamed to src/Agents/ConfigurableAgentsExtensions.cs src/Agents/AddAIAgentsExtensions.cs renamed to src/Agents/ConfigurableAgentsExtensions.cs

@@ -1,18 +1,20 @@
 using System.ComponentModel;
+using Devlooped.Agents.AI;
 using Devlooped.Extensions.AI;
 using Microsoft.Agents.AI;
 using Microsoft.Agents.AI.Hosting;
+using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
 
-namespace Devlooped.Agents.AI;
+namespace Microsoft.Extensions.DependencyInjection;
 
 /// <summary>
 /// Adds configuration-driven agents to an application host.
 /// </summary>
 [EditorBrowsable(EditorBrowsableState.Never)]
-public static class AddAIAgentsExtensions
+public static class ConfigurableAgentsExtensions
 {
     /// <summary>
     /// Adds AI agents to the host application builder based on configuration.
@@ -52,8 +54,17 @@ public static TBuilder AddAIAgents<TBuilder>(this TBuilder builder, Action<strin
 
                 return agent;
             });
+
+            // Also register for case-insensitive lookup, but without duplicating the entry in 
+            // the AgentCatalog, since that will always resolve from above.
+            builder.Services.TryAdd(ServiceDescriptor.KeyedSingleton(new ServiceKey(name), (sp, key)
+                => sp.GetRequiredKeyedService<AIAgent>(name)));
         }
 
         return builder;
     }
+
+    /// <summary>Gets an AI agent by name (case-insensitive) from the service provider.</summary>
+    public static AIAgent? GetIAAgent(this IServiceProvider services, string name)
+        => services.GetKeyedService<AIAgent>(name) ?? services.GetKeyedService<AIAgent>(new ServiceKey(name));
 }

src/Directory.props

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Product>Devlooped AI Extensions</Product>
-    <ImplicitUsings>enable</ImplicitUsings>
+    <ImplicitUsings>true</ImplicitUsings>
     <UserSecretsId>6eb457f9-16bc-49c5-81f2-33399b254e04</UserSecretsId>
 
     <RestoreSources>https://api.nuget.org/v3/index.json;https://pkg.kzu.app/index.json</RestoreSources>

src/Extensions/ConfigurableChatClient.cs

@@ -1,5 +1,6 @@
 using System.ClientModel.Primitives;
 using System.ComponentModel;
+using System.Security.Cryptography;
 using Azure;
 using Azure.AI.Inference;
 using Azure.AI.OpenAI;
@@ -58,11 +59,11 @@ public ConfigurableChatClient(IConfiguration configuration, ILogger logger, stri
     public Task<ChatResponse> GetResponseAsync(IEnumerable<ChatMessage> messages, ChatOptions? options = null, CancellationToken cancellationToken = default)
         => innerClient.GetResponseAsync(messages, options, cancellationToken);
     /// <inheritdoc/>
-    public object? GetService(Type serviceType, object? serviceKey = null)
-        => innerClient.GetService(serviceType, serviceKey);
-    /// <inheritdoc/>
     public IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(IEnumerable<ChatMessage> messages, ChatOptions? options = null, CancellationToken cancellationToken = default)
         => innerClient.GetStreamingResponseAsync(messages, options, cancellationToken);
+    /// <inheritdoc/>
+    public object? GetService(Type serviceType, object? serviceKey = null)
+        => innerClient.GetService(serviceType, serviceKey);
 
     /// <summary>Exposes the optional <see cref="ClientPipelineOptions"/> configured for the client.</summary>
     [EditorBrowsable(EditorBrowsableState.Never)]
@@ -159,4 +160,4 @@ internal class ConfigurableAzureOptions : AzureOpenAIClientOptions
         public string? ApiKey { get; set; }
         public string? ModelId { get; set; }
     }
-}
+}

…c/Extensions/AddChatClientsExtensions.cs …ions/ConfigurableChatClientExtensions.cssrc/Extensions/AddChatClientsExtensions.cs renamed to src/Extensions/ConfigurableChatClientExtensions.cs src/Extensions/AddChatClientsExtensions.cs renamed to src/Extensions/ConfigurableChatClientExtensions.cs

@@ -1,20 +1,20 @@
 using System.ComponentModel;
+using Devlooped.Extensions.AI;
 using Devlooped.Extensions.AI.OpenAI;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using OpenAI;
 
-namespace Devlooped.Extensions.AI;
+namespace Microsoft.Extensions.DependencyInjection;
 
 /// <summary>
 /// Adds configuration-driven chat clients to an application host or service collection.
 /// </summary>
 [EditorBrowsable(EditorBrowsableState.Never)]
-public static class AddChatClientsExtensions
+public static class ConfigurableChatClientExtensions
 {
     /// <summary>
     /// Adds configuration-driven chat clients to the host application builder.
@@ -69,11 +69,19 @@ public static IServiceCollection AddChatClients(this IServiceCollection services
                     return client;
                 },
                 options?.Lifetime ?? ServiceLifetime.Singleton));
+
+            services.TryAdd(new ServiceDescriptor(typeof(IChatClient), new ServiceKey(id),
+                factory: (sp, _) => sp.GetRequiredKeyedService<IChatClient>(id),
+                options?.Lifetime ?? ServiceLifetime.Singleton));
         }
 
         return services;
     }
 
+    /// <summary>Gets a chat client by id (case-insensitive) from the service provider.</summary>
+    public static IChatClient? GetChatClient(this IServiceProvider services, string id)
+        => services.GetKeyedService<IChatClient>(id) ?? services.GetKeyedService<IChatClient>(new ServiceKey(id));
+
     internal class ChatClientOptions : OpenAIClientOptions
     {
         public string? ApiKey { get; set; }

src/Extensions/ServiceKey.cs

@@ -0,0 +1,34 @@
+namespace Devlooped.Extensions.AI;
+
+/// <summary>
+/// An alternative service key that provides more flexible key comparison (case insensitive by default).
+/// </summary>
+/// <param name="key">The service key for use in the dependency injection container.</param>
+/// <param name="comparer">The comparer used for equality comparisons, defaulting to <see cref="StringComparer.OrdinalIgnoreCase"/> if not specified.</param>
+public readonly struct ServiceKey(string key, IEqualityComparer<string?>? comparer = default) : IEquatable<ServiceKey>
+{
+    readonly IEqualityComparer<string?> comparer = comparer ?? StringComparer.OrdinalIgnoreCase;
+
+    /// <summary>
+    /// Gets the original value of the service key.
+    /// </summary>
+    public string Value => key;
+
+    /// <inheritdoc/>
+    public bool Equals(ServiceKey other) => comparer.Equals(Value, other.Value);
+
+    /// <inheritdoc/>
+    public override bool Equals(object? obj) => obj is ServiceKey k && Equals(k);
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => comparer.GetHashCode(Value);
+
+    /// <inheritdoc/>
+    public override string ToString() => Value;
+
+    /// <summary>Compares both keys for equality.</summary>
+    public static bool operator ==(ServiceKey left, ServiceKey right) => left.Equals(right);
+
+    /// <summary>Compares both keys for inequality.</summary>
+    public static bool operator !=(ServiceKey left, ServiceKey right) => !(left == right);
+}