Add LocalChatClientWithTools sample — on-device AI with Apple Intelligence tool calling

10.0/AI/LocalChatClientWithTools/README.md

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+---
+name: .NET MAUI - Local Chat Client with Tools
+description: Chat UI demonstrating on-device Apple Intelligence function calling (tools) with weather, calculator, file listing, system info, and timers — no API keys or cloud services required.
+page_type: sample
+languages:
+- csharp
+- xaml
+products:
+- dotnet-maui
+urlFragment: local-chat-client-with-tools
+---
+
+# LocalChatClientWithTools (MAUI + On-Device Apple Intelligence Tools)
+
+A .NET MAUI sample showing how to enhance an on-device LLM with `Microsoft.Extensions.AI` function calling (tools) using Apple Intelligence. All inference runs locally — **no API keys, no cloud services, no cost**.
+
+| Prompt buttons | Weather tool | Calculator tool | Multi-tool calls |
+|:-:|:-:|:-:|:-:|
+| ![prompts](images/prompts.png) | ![weather](images/weather.png) | ![calculator](images/calculator.png) | ![multi-tool](images/multi_tool.png) |
+
+## What you'll learn
+
+- Using `AppleIntelligenceChatClient` from `Microsoft.Maui.Essentials.AI` as a local `IChatClient`
+- Supplying a set of `AIFunction` tools to `IChatClient` via `ChatOptions.Tools`
+- Implementing strongly described tool schemas (JSON schema) for better argument selection
+- Resolving user-friendly locations to coordinates with the free [open-meteo.com](https://open-meteo.com) API
+- Building a MAUI chat UI with template selectors for different message types (text, tool calls)
+- Running AI inference entirely on-device with no external API keys
+
+## Prerequisites
+
+- .NET 10 SDK
+- iOS 26.0+ or macCatalyst 26.0+ device/simulator with Apple Intelligence enabled
+- No API keys or cloud accounts needed
+
+## Tools implemented
+
+| Tool | Name | Purpose | Notes |
+|------|------|---------|-------|
+| WeatherTool | `get_weather` | Current conditions for a location | Geocodes via open-meteo.com, then fetches forecast — free, no API key |
+| CalculatorTool | `calculate` | Evaluate arithmetic / percentages | Sanitizes expression & returns formatted result |
+| FileOperationsTool | `list_files` | List files & folders in a common or given path | Limits count; resolves shortcuts (Documents, Desktop, Downloads) |
+| SystemInfoTool | `get_system_info` | Battery, storage, memory, device info | Returns live device values on Apple platforms |
+| TimerTool | `set_timer` | Create a one‑shot timer with title | Keeps in-memory timers; shows alert on completion |
+
+Each tool is created via `AIFunctionFactory.Create` using strongly-typed methods and AOT-compatible JSON serialization via `ToolJsonContext`.
+
+## Key files
+
+- `MauiProgram.cs` – Registers `IChatClient` via `AppleIntelligenceChatClient` with `UseFunctionInvocation()` for automatic tool dispatch, and registers all tool functions.
+- `Services/Tools/*.cs` – Tool implementations using `AIFunctionFactory.Create` for clean, factory-based tool registration.
+- `ViewModels/ChatViewModel.cs` – Collects tools and invokes `_chatClient.GetStreamingResponseAsync` passing `ChatOptions.Tools`.
+- `ViewModels/ChatMessageViewModel.cs` – Base view model for chat messages, with `TextMessageViewModel` and `ToolCallMessageViewModel` subclasses.
+- `MainPage.xaml` – Chat layout with `ChatTemplateSelector`, EmptyView sample prompts, and a `Clear` toolbar item (resets to EmptyView).
+
+## Sample prompts
+
+Try:
+
+- "What's the weather in Seattle?"
+- "Calculate 15% tip on $47.50"
+- "List the files in my Documents folder"
+- "Show me current battery level and available storage"
+- "Set a 5-minute timer for my coffee break"
+- "What's 25 × 18 + 150?"
+- "Check the weather in Tokyo and Cape Town"
+
+## Run
+
+```bash
+# iOS simulator
+dotnet build -f net10.0-ios -t:Run
+
+# macCatalyst
+dotnet build -f net10.0-maccatalyst -t:Run
+```
+
+Use a sample prompt or type your own. Use the toolbar **Clear** to reset and revisit the instructional prompt list.
+
+> **Note:** This sample only runs on Apple platforms (iOS / macCatalyst) with Apple Intelligence. Other platforms will throw `PlatformNotSupportedException` at startup.
+
+## Architecture highlights
+
+### Tool invocation flow
+
+1. User sends natural language input.
+2. `ChatViewModel` builds `ChatOptions` with the registered tool objects.
+3. `AppleIntelligenceChatClient` (wrapped with `UseFunctionInvocation()`) decides if any tool(s) should be invoked and executes them, passing JSON arguments that conform to each tool's declared schema.
+4. Tool result objects surface in the assistant response and are bound to specialized UI cards.
+5. UI shows structured cards or plain text depending on `ChatMessage` flags.
+
+### On-device vs. cloud
+
+This sample is a local-only variant of the `ChatClientWithTools` sample. The key differences:
+
+| | ChatClientWithTools | LocalChatClientWithTools |
+|---|---|---|
+| **LLM provider** | Azure OpenAI (cloud) | Apple Intelligence (on-device) |
+| **API keys** | Required (Azure + optional OpenWeatherMap) | None |
+| **Weather API** | OpenWeatherMap (key required) | open-meteo.com (free, keyless) |
+| **Platforms** | Windows, iOS, macCatalyst, Android | iOS, macCatalyst only |
+| **NuGet packages** | Azure.AI.OpenAI, Microsoft.Extensions.AI.OpenAI | Microsoft.Maui.Essentials.AI |
+
+### UI features
+
+- EmptyView with categorized starter buttons (Weather / Calculator / Files / System Info / Timers).
+- Rich result cards styled with color-coded borders.
+- Toolbar "Clear" to wipe conversation state quickly (teaching scenario friendly).
+- Auto-scroll to the latest message.
+
+## Useful references
+
+- Microsoft.Extensions.AI overview: <https://learn.microsoft.com/dotnet/ai/microsoft-extensions-ai>
+- Apple Intelligence in .NET MAUI: <https://learn.microsoft.com/dotnet/maui/platform-integration/communication/ai>
+- CommunityToolkit.Mvvm: <https://learn.microsoft.com/dotnet/communitytoolkit/mvvm/>
+
+## Notes
+
+- Requires iOS 26.0+ or macCatalyst 26.0+ with Apple Intelligence available and enabled.
+- All AI inference runs on-device — no data leaves the device for LLM processing.
+- Weather data comes from [open-meteo.com](https://open-meteo.com) (free, open-source weather API).
+- Timers are in-memory only (lost on app exit) and surface completion via a `DisplayAlertAsync` dialog.
+- File operations are intentionally conservative; expand with care for security.
+- This sample emphasizes pedagogy over exhaustive production hardening.
+
+---
+For the cloud-hosted version of this sample, see `ChatClientWithTools` in the same folder tree.

10.0/AI/LocalChatClientWithTools/src/App.xaml

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+<?xml version = "1.0" encoding = "UTF-8" ?>
+<Application xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:local="clr-namespace:LocalChatClientWithTools"
+             x:Class="LocalChatClientWithTools.App">
+    <Application.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="Resources/Styles/Colors.xaml" />
+                <ResourceDictionary Source="Resources/Styles/Styles.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+        </ResourceDictionary>
+    </Application.Resources>
+</Application>

10.0/AI/LocalChatClientWithTools/src/App.xaml.cs

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+namespace LocalChatClientWithTools;
+
+public partial class App : Application
+{
+	public App()
+	{
+		InitializeComponent();
+	}
+
+	protected override Window CreateWindow(IActivationState? activationState)
+	{
+		return new Window(new AppShell());
+	}
+}

10.0/AI/LocalChatClientWithTools/src/AppShell.xaml

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+<?xml version="1.0" encoding="UTF-8" ?>
+<Shell
+    x:Class="LocalChatClientWithTools.AppShell"
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:local="clr-namespace:LocalChatClientWithTools"
+    Title="LocalChatClientWithTools">
+
+    <ShellContent
+        Title="Home"
+        ContentTemplate="{DataTemplate local:MainPage}"
+        Route="MainPage" />
+
+</Shell>

10.0/AI/LocalChatClientWithTools/src/AppShell.xaml.cs

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+namespace LocalChatClientWithTools;
+
+public partial class AppShell : Shell
+{
+	public AppShell()
+	{
+		InitializeComponent();
+	}
+}

10.0/AI/LocalChatClientWithTools/src/ChatTemplateSelector.cs

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+using LocalChatClientWithTools.ViewModels;
+
+namespace LocalChatClientWithTools;
+
+public class ChatTemplateSelector : DataTemplateSelector
+{
+    public DataTemplate? TextTemplate { get; set; }
+    public DataTemplate? ToolCallTemplate { get; set; }
+
+    protected override DataTemplate OnSelectTemplate(object item, BindableObject container) => item switch
+    {
+        ToolCallMessageViewModel => ToolCallTemplate!,
+        TextMessageViewModel => TextTemplate!,
+        _ => TextTemplate!
+    };
+}

10.0/AI/LocalChatClientWithTools/src/GlobalXmlns.cs

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+[assembly: XmlnsDefinition("http://schemas.microsoft.com/dotnet/maui/global", "LocalChatClientWithTools")]
+[assembly: XmlnsDefinition("http://schemas.microsoft.com/dotnet/maui/global", "LocalChatClientWithTools.ViewModels")]
+[assembly: XmlnsDefinition("http://schemas.microsoft.com/dotnet/maui/global", "Syncfusion.Maui.Toolkit.TextInputLayout", AssemblyName = "Syncfusion.Maui.Toolkit")]

10.0/AI/LocalChatClientWithTools/src/LocalChatClientWithTools.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+	<PropertyGroup>
+		<TargetFrameworks>net10.0-android;net10.0-ios;net10.0-maccatalyst</TargetFrameworks>
+		<TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net10.0-windows10.0.19041.0</TargetFrameworks>
+
+		<!-- Note for MacCatalyst:
+		The default runtime is maccatalyst-x64, except in Release config, in which case the default is maccatalyst-x64;maccatalyst-arm64.
+		When specifying both architectures, use the plural <RuntimeIdentifiers> instead of the singular <RuntimeIdentifier>.
+		The Mac App Store will NOT accept apps with ONLY maccatalyst-arm64 indicated;
+		either BOTH runtimes must be indicated or ONLY macatalyst-x64. -->
+		<!-- For example: <RuntimeIdentifiers>maccatalyst-x64;maccatalyst-arm64</RuntimeIdentifiers> -->
+
+		<OutputType>Exe</OutputType>
+		<RootNamespace>LocalChatClientWithTools</RootNamespace>
+		<UseMaui>true</UseMaui>
+		<SingleProject>true</SingleProject>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
+
+		<NoWarn>$(NoWarn);MAUIAI0001;CA2252</NoWarn>
+
+		<!-- Enable implicit + global XAML xmlns for .NET 10 previews -->
+		<DefineConstants>$(DefineConstants);MauiAllowImplicitXmlnsDeclaration</DefineConstants>
+		<EnablePreviewFeatures>true</EnablePreviewFeatures>
+
+		<!-- Display name -->
+		<ApplicationTitle>LocalChatClientWithTools</ApplicationTitle>
+
+		<!-- App Identifier -->
+		<ApplicationId>com.companyname.localchatclientwithtools</ApplicationId>
+
+		<!-- Versions -->
+		<ApplicationDisplayVersion>1.0</ApplicationDisplayVersion>
+		<ApplicationVersion>1</ApplicationVersion>
+
+		<!-- To develop, package, and publish an app to the Microsoft Store, see: https://aka.ms/MauiTemplateUnpackaged -->
+		<WindowsPackageType>None</WindowsPackageType>
+
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">26.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'maccatalyst'">26.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'">21.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.17763.0</SupportedOSPlatformVersion>
+		<TargetPlatformMinVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.17763.0</TargetPlatformMinVersion>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<!-- App Icon -->
+		<MauiIcon Include="Resources\AppIcon\appicon.svg" ForegroundFile="Resources\AppIcon\appiconfg.svg" Color="#512BD4" />
+
+		<!-- Splash Screen -->
+		<MauiSplashScreen Include="Resources\Splash\splash.svg" Color="#512BD4" BaseSize="128,128" />
+
+		<!-- Images -->
+		<MauiImage Include="Resources\Images\*" />
+
+		<!-- Custom Fonts -->
+		<MauiFont Include="Resources\Fonts\*" />
+
+		<!-- Raw Assets (also remove the "Resources\Raw" prefix) -->
+		<MauiAsset Include="Resources\Raw\**" LogicalName="%(RecursiveDir)%(Filename)%(Extension)" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Microsoft.Extensions.AI" Version="10.3.0" />
+		<PackageReference Include="Microsoft.Maui.Essentials.AI" Version="10.0.50-preview.1.26158.1" />
+		<PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0" />
+		<PackageReference Include="Microsoft.Maui.Controls" Version="$(MauiVersion)" />
+		<PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="10.0.0" />
+		<PackageReference Include="Syncfusion.Maui.Toolkit" Version="1.0.6" />
+		<PackageReference Include="Microsoft.Extensions.Http" Version="10.0.0" />
+	</ItemGroup>
+
+</Project>

10.0/AI/LocalChatClientWithTools/src/LocalChatClientWithTools.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31903.59
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LocalChatClientWithTools", "LocalChatClientWithTools.csproj", "{9FB143A1-5BC5-40A3-B332-BA816CF1CE04}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{9FB143A1-5BC5-40A3-B332-BA816CF1CE04}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9FB143A1-5BC5-40A3-B332-BA816CF1CE04}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9FB143A1-5BC5-40A3-B332-BA816CF1CE04}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9FB143A1-5BC5-40A3-B332-BA816CF1CE04}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal