Community.Microsoft.Extensions.AI.CoreML 0.1.0-preview1

Community.Microsoft.Extensions.AI.CoreML

Use Apple Intelligence on-device models directly from .NET

What is this?

Community.Microsoft.Extensions.AI.CoreML is an open-source IChatClient implementation for the Microsoft.Extensions.AI abstraction that talks directly to Apple's on-device Foundation Models (Apple Intelligence) via P/Invoke — no network calls, no MAUI dependencies.

This lets you use the same IChatClient interface you already know from OpenAI/Azure OpenAI, but backed by the private, local model that runs on any Apple Silicon Mac with macOS 26+.

Why?

Apple Intelligence runs fully on-device, which means:

• Free — no API costs
• Private — data never leaves your machine
• Fast — no network latency
• Offline — works without internet

The catch: Apple's Foundation Models framework is a Swift/Objective-C API. Existing .NET solutions require installing the full MAUI workload. This library instead ships a thin native C bridge (compiled as a .dylib) that is P/Invoked from C#, making the dependency footprint minimal.

Requirements

Runtime Guard Behavior

• On macOS earlier than 26.0, native bridge calls fail fast with a clear unsupported-platform error.
• aib_is_available returns false when the OS is below 26.0.
• On supported systems, availability is checked against an instantiated SystemLanguageModel.

Installation

dotnet add package Community.Microsoft.Extensions.AI.CoreML

⚠️ The NuGet package bundles the pre-built native bridge dylib for macOS arm64. No separate installation is required.

Quick Start

using Community.Microsoft.Extensions.AI.CoreML;
using Microsoft.Extensions.AI;

IChatClient client = new AppleIntelligenceChatClient();

var response = await client.GetResponseAsync([
    new ChatMessage(ChatRole.User, "Summarise the key ideas of stoicism in three bullet points.")
]);

Console.WriteLine(response.Text);

Dependency Injection

builder.Services.AddChatClient(
    new AppleIntelligenceChatClient()
);

How it Works

flowchart TD
    App[".NET Application\nIChatClient"]
    Client["AppleIntelligenceChatClient\nP/Invoke"]
    Dylib["libAppleIntelligenceBridge.dylib\nSwift / C bridge"]
    FM["Apple Foundation Models\nLanguageModelSession"]

    App -->|"Microsoft.Extensions.AI"| Client
    Client -->|"P/Invoke  ·  arm64"| Dylib
    Dylib -->|"Swift API"| FM

The library ships a thin Swift C-bridge (@_cdecl exported functions) compiled into a native dylib. The C# layer P/Invokes these functions and maps them to the IChatClient / IStreamingChatClient contracts.

For more detail see docs/architecture.md.

Related Projects

• apfel — Apple Intelligence CLI & OpenAI-compatible HTTP server (Swift)
• apple-on-device-openai — SwiftUI app exposing Foundation Models as OpenAI server
• Microsoft.Extensions.AI — the abstraction this library implements

Contributing

Contributions are welcome! See docs/plan.md for the current implementation roadmap.

1. Fork the repo
2. Create a feature branch
3. Submit a PR against main

License

MIT — © Community Contributors