docs: Add MEAI guide to mkdocs site

Comprehensive guide covering IChatClient, IEmbeddingGenerator,
streaming, tool calling, structured output, images, and CustomProviders.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: HavenDV

docs/guides/meai.md

@@ -0,0 +1,207 @@
+# Microsoft.Extensions.AI Integration
+
+The `tryAGI.OpenAI` SDK natively implements [Microsoft.Extensions.AI](https://learn.microsoft.com/dotnet/ai/microsoft-extensions-ai/) interfaces, providing a unified abstraction layer for AI services across .NET applications.
+
+## Supported Interfaces
+
+| Interface | Description |
+|-----------|-------------|
+| `IChatClient` | Chat completions with text, streaming, tool calling, images, and structured output |
+| `IEmbeddingGenerator<string, Embedding<float>>` | Text embeddings with custom dimensions |
+
+## IChatClient
+
+### Basic Chat
+
+```csharp
+using OpenAI;
+using Microsoft.Extensions.AI;
+
+using var client = new OpenAiClient("API_KEY");
+IChatClient chatClient = client;
+
+var response = await chatClient.GetResponseAsync(
+    "Say hello!",
+    new ChatOptions { ModelId = "gpt-4o-mini" });
+
+Console.WriteLine(response.Messages[0].Text);
+```
+
+### Streaming
+
+```csharp
+await foreach (var update in chatClient.GetStreamingResponseAsync(
+    "Count from 1 to 10.",
+    new ChatOptions { ModelId = "gpt-4o-mini" }))
+{
+    Console.Write(string.Concat(update.Contents.OfType<TextContent>().Select(c => c.Text)));
+}
+```
+
+### System Messages
+
+```csharp
+var messages = new List<ChatMessage>
+{
+    new(ChatRole.System, "You are a pirate. Always respond with 'Arrr!'."),
+    new(ChatRole.User, "Hello!"),
+};
+
+var response = await chatClient.GetResponseAsync(
+    messages,
+    new ChatOptions { ModelId = "gpt-4o-mini" });
+```
+
+### Tool Calling
+
+```csharp
+var weatherTool = AIFunctionFactory.Create(
+    (string city) => city switch
+    {
+        "Paris" => "22C, sunny",
+        "London" => "15C, cloudy",
+        _ => "Unknown",
+    },
+    name: "GetWeather",
+    description: "Gets the current weather for a city");
+
+var response = await chatClient.GetResponseAsync(
+    "What's the weather in Paris?",
+    new ChatOptions
+    {
+        ModelId = "gpt-4o-mini",
+        Tools = [weatherTool],
+    });
+```
+
+### Structured Output (JSON Schema)
+
+```csharp
+var schema = System.Text.Json.JsonDocument.Parse("""
+{
+    "type": "object",
+    "properties": {
+        "name": { "type": "string" },
+        "age": { "type": "integer" }
+    },
+    "required": ["name", "age"],
+    "additionalProperties": false
+}
+""").RootElement;
+
+var response = await chatClient.GetResponseAsync(
+    "Return info about Alice who is 30.",
+    new ChatOptions
+    {
+        ModelId = "gpt-4o-mini",
+        ResponseFormat = new ChatResponseFormatJson(schema, "person", "A person object"),
+    });
+```
+
+### Image Content
+
+```csharp
+var message = new ChatMessage(ChatRole.User, []);
+message.Contents.Add(new TextContent("What is in this image?"));
+message.Contents.Add(new UriContent(
+    new Uri("https://example.com/photo.png"),
+    mediaType: "image/png"));
+
+var response = await chatClient.GetResponseAsync(
+    [message],
+    new ChatOptions { ModelId = "gpt-4o-mini" });
+```
+
+### Temperature, TopP, and Stop Sequences
+
+```csharp
+var response = await chatClient.GetResponseAsync(
+    "What is 2+2?",
+    new ChatOptions
+    {
+        ModelId = "gpt-4o-mini",
+        Temperature = 0f,
+        TopP = 1f,
+        StopSequences = ["5"],
+    });
+```
+
+### Additional Properties
+
+Pass provider-specific parameters via `AdditionalProperties`:
+
+```csharp
+var options = new ChatOptions
+{
+    ModelId = "gpt-4o-mini",
+    Temperature = 0f,
+};
+options.AdditionalProperties ??= new AdditionalPropertiesDictionary();
+options.AdditionalProperties["seed"] = 42;
+
+var response = await chatClient.GetResponseAsync(messages, options);
+```
+
+## IEmbeddingGenerator
+
+### Basic Embeddings
+
+```csharp
+using OpenAI;
+using Microsoft.Extensions.AI;
+
+using var client = new OpenAiClient("API_KEY");
+IEmbeddingGenerator<string, Embedding<float>> generator = client;
+
+var result = await generator.GenerateAsync(
+    ["Hello, world!"],
+    new EmbeddingGenerationOptions { ModelId = "text-embedding-3-small" });
+
+Console.WriteLine($"Dimensions: {result[0].Vector.Length}");
+```
+
+### Batch Embeddings
+
+```csharp
+var result = await generator.GenerateAsync(
+    ["Hello", "How are you?", "Goodbye"],
+    new EmbeddingGenerationOptions { ModelId = "text-embedding-3-small" });
+
+Console.WriteLine($"Generated {result.Count} embeddings");
+```
+
+### Custom Dimensions
+
+```csharp
+var result = await generator.GenerateAsync(
+    ["Hello, world!"],
+    new EmbeddingGenerationOptions
+    {
+        ModelId = "text-embedding-3-small",
+        Dimensions = 256,
+    });
+
+Console.WriteLine($"Dimensions: {result[0].Vector.Length}"); // 256
+```
+
+## Custom Providers
+
+All 15+ custom providers support the same MEAI interfaces:
+
+```csharp
+using OpenAI;
+using Microsoft.Extensions.AI;
+
+// Any CustomProvider works as IChatClient and IEmbeddingGenerator
+using var client = CustomProviders.Groq("API_KEY");
+// or: CustomProviders.DeepInfra("API_KEY")
+// or: CustomProviders.Together("API_KEY")
+// or: CustomProviders.Azure("API_KEY", "ENDPOINT")
+// or: CustomProviders.DeepSeek("API_KEY")
+// or: any other CustomProvider
+
+IChatClient chatClient = client;
+var response = await chatClient.GetResponseAsync(
+    "Hello!",
+    new ChatOptions { ModelId = "llama-3.3-70b-versatile" });
+```

mkdocs.yml

@@ -1,6 +1,8 @@
 site_name: OpenAI .NET Documentation
 nav:
 - Overview: index.md
+- Guides:
+  - Microsoft.Extensions.AI: guides/meai.md
 # EXAMPLES:START
 - Examples:
   - Assistants: