Allow retrieving native client options from chat client

If the caller knows what type of options it's dealing with (OpenAIClientOptions, AzureOpenAIClientOptions, AzureAIInferenceClientOptions or GrokClientOptions), it can request the specific type. As a fallback, an untyped service with the key `options` is provided.

Author: kzu

src/Extensions/ChatClientProviders.cs

@@ -1,5 +1,7 @@
 using System.ClientModel;
 using Azure;
+using Azure.AI.Inference;
+using Azure.AI.OpenAI;
 using Devlooped.Extensions.AI.OpenAI;
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Configuration;
@@ -29,7 +31,9 @@ public IChatClient Create(IConfigurationSection section)
         Throw.IfNullOrEmpty(options.ApiKey, $"{section.Path}:apikey");
         Throw.IfNullOrEmpty(options.ModelId, $"{section.Path}:modelid");
 
-        return new OpenAIClient(new ApiKeyCredential(options.ApiKey), options).GetChatClient(options.ModelId).AsIChatClient();
+        return new ProviderOptionsChatClient<OpenAIClientOptions>(
+            new OpenAIClient(new ApiKeyCredential(options.ApiKey), options).GetChatClient(options.ModelId).AsIChatClient(),
+            options);
     }
 
     internal sealed class OpenAIProviderOptions : OpenAIClientOptions
@@ -61,7 +65,9 @@ public IChatClient Create(IConfigurationSection section)
         Throw.IfNullOrEmpty(options.ModelId, $"{section.Path}:modelid");
         Throw.IfNull(options.Endpoint, $"{section.Path}:endpoint");
 
-        return new AzureOpenAIChatClient(options.Endpoint, new AzureKeyCredential(options.ApiKey), options.ModelId, options);
+        return new ProviderOptionsChatClient<AzureOpenAIClientOptions>(
+            new AzureOpenAIChatClient(options.Endpoint, new AzureKeyCredential(options.ApiKey), options.ModelId, options),
+            options);
     }
 
     internal sealed class AzureOpenAIProviderOptions : Azure.AI.OpenAI.AzureOpenAIClientOptions
@@ -94,8 +100,10 @@ public IChatClient Create(IConfigurationSection section)
         Throw.IfNullOrEmpty(options.ModelId, $"{section.Path}:modelid");
         Throw.IfNull(options.Endpoint, $"{section.Path}:endpoint");
 
-        return new Azure.AI.Inference.ChatCompletionsClient(options.Endpoint, new AzureKeyCredential(options.ApiKey), options)
-            .AsIChatClient(options.ModelId);
+        return new ProviderOptionsChatClient<AzureAIInferenceClientOptions>(
+            new Azure.AI.Inference.ChatCompletionsClient(options.Endpoint, new AzureKeyCredential(options.ApiKey), options)
+                .AsIChatClient(options.ModelId),
+            options);
     }
 
     internal sealed class AzureInferenceProviderOptions : Azure.AI.Inference.AzureAIInferenceClientOptions
@@ -127,13 +135,26 @@ public IChatClient Create(IConfigurationSection section)
         Throw.IfNullOrEmpty(options.ApiKey, $"{section.Path}:apikey");
         Throw.IfNullOrEmpty(options.ModelId, $"{section.Path}:modelid");
 
-        return new GrokClient(options.ApiKey, section.Get<GrokClientOptions>() ?? new())
-            .AsIChatClient(options.ModelId);
+        return new ProviderOptionsChatClient<GrokClientOptions>(
+            new GrokClient(options.ApiKey, options).AsIChatClient(options.ModelId),
+            options);
     }
 
-    internal sealed class GrokProviderOptions
+    internal sealed class GrokProviderOptions : GrokClientOptions
     {
         public string? ApiKey { get; set; }
         public string? ModelId { get; set; }
     }
 }
+
+sealed class ProviderOptionsChatClient<TOptions>(IChatClient inner, TOptions options) : DelegatingChatClient(inner)
+    where TOptions : notnull
+{
+    public override object? GetService(Type serviceType, object? serviceKey = null)
+        => IsOptionsRequest(serviceType, serviceKey) ? options : inner.GetService(serviceType, serviceKey);
+
+    bool IsOptionsRequest(Type serviceType, object? serviceKey)
+        => serviceType == typeof(object) ?
+           serviceKey is string key && string.Equals(key, "options", StringComparison.OrdinalIgnoreCase) :
+           typeof(TOptions).IsAssignableFrom(serviceType);
+}

src/Tests/ConfigurableClientTests.cs

@@ -1,6 +1,8 @@
 using Microsoft.Extensions.AI;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using OpenAI;
+using xAI;
 
 namespace Devlooped.Extensions.AI;
 
@@ -32,6 +34,37 @@ public void CanConfigureClients()
         Assert.Equal("xai", grok.GetRequiredService<ChatClientMetadata>().ProviderName);
     }
 
+    [Fact]
+    public void CanGetClientOptions()
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ai:clients:openai:modelid"] = "gpt-4.1.nano",
+                ["ai:clients:openai:ApiKey"] = "sk-asdfasdf",
+                ["ai:clients:grok:modelid"] = "grok-4-fast",
+                ["ai:clients:grok:ApiKey"] = "xai-asdfasdf",
+                ["ai:clients:grok:endpoint"] = "https://api.x.ai",
+            })
+            .Build();
+
+        var services = new ServiceCollection()
+            .AddSingleton<IConfiguration>(configuration)
+            .AddChatClients(configuration)
+            .BuildServiceProvider();
+
+        var openai = services.GetRequiredKeyedService<IChatClient>("openai");
+        var grok = services.GetRequiredKeyedService<IChatClient>("grok");
+
+        // Untyped by name+object
+        Assert.NotNull(openai.GetService<object>("options"));
+        // Typed to concrete options, no need for key
+        Assert.NotNull(openai.GetService<OpenAIClientOptions>());
+
+        Assert.NotNull(grok.GetService<object>("Options"));
+        Assert.NotNull(grok.GetService<GrokClientOptions>());
+    }
+
     [Fact]
     public void CanGetFromAlternativeKey()
     {
@@ -259,4 +292,108 @@ public void CanConfigureAzureOpenAI()
         Assert.Equal("azure.ai.openai", client.GetRequiredService<ChatClientMetadata>().ProviderName);
         Assert.Equal("gpt-5", client.GetRequiredService<ChatClientMetadata>().DefaultModelId);
     }
+
+    [Fact]
+    public void CanInspectOpenAIProviderOptions()
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ai:clients:openai:modelid"] = "gpt-4.1.nano",
+                ["ai:clients:openai:apikey"] = "sk-asdfasdf",
+                ["ai:clients:openai:UserAgentApplicationId"] = "myapp/1.0",
+            })
+            .Build();
+
+        var services = new ServiceCollection()
+            .AddSingleton<IConfiguration>(configuration)
+            .AddChatClients(configuration)
+            .BuildServiceProvider();
+
+        var client = services.GetRequiredKeyedService<IChatClient>("openai");
+        var options = Assert.IsType<OpenAIChatClientProvider.OpenAIProviderOptions>(
+            client.GetService(typeof(object), "OpTiOnS"));
+
+        Assert.Same(options, client.GetService(typeof(OpenAIChatClientProvider.OpenAIProviderOptions), "options"));
+        Assert.Equal("gpt-4.1.nano", options.ModelId);
+        Assert.Equal("myapp/1.0", options.UserAgentApplicationId);
+    }
+
+    [Fact]
+    public void CanInspectAzureOpenAIProviderOptions()
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ai:clients:chat:modelid"] = "gpt-5",
+                ["ai:clients:chat:apikey"] = "asdfasdf",
+                ["ai:clients:chat:endpoint"] = "https://chat.openai.azure.com/",
+                ["ai:clients:chat:UserAgentApplicationId"] = "myapp/1.0",
+            })
+            .Build();
+
+        var services = new ServiceCollection()
+            .AddSingleton<IConfiguration>(configuration)
+            .AddChatClients(configuration)
+            .BuildServiceProvider();
+
+        var client = services.GetRequiredKeyedService<IChatClient>("chat");
+        var options = Assert.IsType<AzureOpenAIChatClientProvider.AzureOpenAIProviderOptions>(
+            client.GetService(typeof(object), "options"));
+
+        Assert.Same(options, client.GetService(typeof(AzureOpenAIChatClientProvider.AzureOpenAIProviderOptions), "OPTIONS"));
+        Assert.Equal(new Uri("https://chat.openai.azure.com/"), options.Endpoint);
+        Assert.Equal("myapp/1.0", options.UserAgentApplicationId);
+    }
+
+    [Fact]
+    public void CanInspectAzureInferenceProviderOptions()
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ai:clients:chat:modelid"] = "gpt-5",
+                ["ai:clients:chat:apikey"] = "asdfasdf",
+                ["ai:clients:chat:endpoint"] = "https://ai.azure.com/.default",
+            })
+            .Build();
+
+        var services = new ServiceCollection()
+            .AddSingleton<IConfiguration>(configuration)
+            .AddChatClients(configuration)
+            .BuildServiceProvider();
+
+        var client = services.GetRequiredKeyedService<IChatClient>("chat");
+        var options = Assert.IsType<AzureAIInferenceChatClientProvider.AzureInferenceProviderOptions>(
+            client.GetService(typeof(object), "options"));
+
+        Assert.Same(options, client.GetService(typeof(AzureAIInferenceChatClientProvider.AzureInferenceProviderOptions), "OPTIONS"));
+        Assert.Equal(new Uri("https://ai.azure.com/.default"), options.Endpoint);
+        Assert.Equal("gpt-5", options.ModelId);
+    }
+
+    [Fact]
+    public void CanInspectGrokProviderOptions()
+    {
+        var configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ai:clients:grok:modelid"] = "grok-4-fast",
+                ["ai:clients:grok:apikey"] = "xai-asdfasdf",
+                ["ai:clients:grok:endpoint"] = "https://api.x.ai",
+            })
+            .Build();
+
+        var services = new ServiceCollection()
+            .AddSingleton<IConfiguration>(configuration)
+            .AddChatClients(configuration)
+            .BuildServiceProvider();
+
+        var client = services.GetRequiredKeyedService<IChatClient>("grok");
+        var options = Assert.IsType<GrokChatClientProvider.GrokProviderOptions>(
+            client.GetService(typeof(object), "options"));
+
+        Assert.Same(options, client.GetService(typeof(GrokChatClientProvider.GrokProviderOptions), "OPTIONS"));
+        Assert.Equal("grok-4-fast", options.ModelId);
+    }
 }