[AI] Windows Copilot Runtime (Phi Silica) support for Essentials.AI by mattleibow · Pull Request #33605 · dotnet/maui

mattleibow · 2026-01-19T17:00:05Z

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Summary

Adds Windows Copilot Runtime (Phi Silica) support to Microsoft.Maui.Essentials.AI, enabling on-device AI capabilities through the Microsoft.Extensions.AI abstractions on Windows.

New Components

Component	Description
PhiSilicaChatClient	Full `IChatClient` implementation for Windows Copilot Runtime — synchronous & streaming responses, lazy model init, cancellation support, middleware compatible
PhiSilicaModelFactory	Internal model availability checking and lazy initialization with proper disposal
PhiSilicaExtensions	`LanguageModel.AsIChatClient()` extension method
AppContentIndexerSearchService	`ISemanticSearchService` using Windows AppContentIndexer — OS handles embeddings internally

Capabilities

Feature	Status
Chat Completion	✅ Via `GetResponseAsync()` (streaming internally)
Streaming Responses	⚠️ Returns full response as single update (Windows API limitation)
System Prompts	✅ Via `LanguageModel.CreateContext()`
Temperature / TopK / TopP	✅ Supported
Semantic Search	✅ Via AppContentIndexer
Function/Tool Calling	❌ Not available in Phi Silica API
Structured JSON Output	❌ Not available — uses `PromptBasedSchemaClient` middleware

Sample App Changes

The Essentials.AI.Sample now uses Phi Silica on Windows (on-device) and falls back to OpenAI on other platforms. PromptBasedSchemaClient middleware and DisplayName attributes replace JsonPropertyName for cross-platform schema compatibility.

Dependencies

Package	Version
Microsoft.WindowsAppSDK	2.0.0-experimental6
Microsoft.Web.WebView2	1.0.3650.58

Test Coverage

PhiSilicaChatClientTests — instantiation and metadata verification

Requirements

Windows 10 version 26100.0+ with Copilot Runtime enabled
Packaged app deployment (MSIX)

github-actions · 2026-03-18T23:27:48Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 33605

Or

Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 33605"

- New LandmarkDetailPage with AI travel tips, similar destinations, tags - Semantic search bar on LandmarksPage with debounced filtering - ISemanticSearchService abstraction with EmbeddingSearchService and AppContentIndexerSearchService - Refactored DataService to use ISemanticSearchService instead of IEmbeddingGenerator - TaggingService switched to plaintext comma-separated parsing - TravelPlannerExecutor uses prompt-based JSON instead of structured output - TripPlanningPage auto-starts itinerary generation (no initial state) - Merged LandmarkTripView into TripPlanningPage, deleted unused views - Removed NonFunctionInvokingChatClient reference - Language picker moved to LandmarkDetailPage Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Fix navigation crash: add missing Gray700 color to Colors.xaml - Fix gradient overlays: remove broken BoxView global style, use transparent-white gradients - Replace SearchBar with borderless Entry, remove native border/focus ring on MacCatalyst - Edge-to-edge horizontal scrollers with aligned padding - Scrolling gradient + solid background pattern on detail and trip planning pages - Safe area: use SafeAreaEdges=None on root Grids, Container on back buttons - Debounced search with Timer instead of per-keystroke async work - Use IDispatcher instead of MainThread.BeginInvokeOnMainThread - Only-once AI initialization on LandmarkDetailPage - Migrate BackgroundColor to Background across pages and views - Fix null dereference warnings in DataService Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

… Bunaken landmark - PromptBasedSchemaClient middleware for prompt-based structured output - Fixed chat bubble alignment and scroll-to-end on Windows - Removed LanguagePreferenceService — language passed via navigation - Added Temperature for creative agents (0.8) and travel tips (0.9) - Fixed WeatherService locale issue (InvariantCulture) - Added weather display to LandmarkDetailPage - Map placeholder on Windows (OnPlatform) - TravelPlanResult uses short JsonPropertyName for SLM reliability - StreamingResponseHandler passthrough mode + 7 unit tests - Added Bunaken Marine Park (Manado, Indonesia) landmark - Fixed agent instruction examples Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…tenatedText) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

PromptBasedSchemaClient reads DisplayName for prompt-based JSON schema generation, which works across all platforms including Phi Silica. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

DisplayName does not work on properties for JSON schema generation — it only applies at the class/type level. JsonPropertyName is needed for PromptBasedSchemaClient to emit the correct short property names. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Introduce AI capabilities for Windows platform including: Core Components: - PhiSilicaChatClient: Chat completion client using Windows Copilot Runtime (Phi Silica) with streaming support via IChatClient - PhiSilicaEmbeddingGenerator: Text embedding generator using LanguageModel.GenerateEmbeddingVectorAsync via IEmbeddingGenerator - PhiSilicaExtensions: Convenience methods to convert LanguageModel to IChatClient and IEmbeddingGenerator - (internal) PhiSilicaModelFactory: Model availability checking and lazy initialization with proper disposal handling Samples: - Update Essentials.AI.Sample to use Phi Silica on Windows, falling back to OpenAI on other platforms - Configure packaged app deployment for Windows AI API access Tests: - Unit tests for PhiSilicaChatClient construction and metadata - Unit tests for PhiSilicaEmbeddingGenerator construction and metadata Dependencies: - Update Windows App SDK to 2.0.0-experimental4 (required for AI APIs) - Update WebView2 to 1.0.3650.58 Requires Windows 10.0.26100.0+ with Copilot Runtime support enabled.

… sample improvements - Updated WinAppSDK from experimental4 to experimental6 - Fixed PhiSilicaChatClient streaming using shared StreamingResponseHandler - Removed PhiSilicaEmbeddingGenerator (LLM token embeddings unsuitable for similarity) - Added ISemanticSearchService abstraction with EmbeddingSearchService and AppContentIndexerSearchService - New LandmarkDetailPage with AI travel tips, similar destinations, semantic search - Refactored DataService to use ISemanticSearchService - TaggingService switched to plaintext parsing for cross-platform compatibility - TripPlanningPage auto-starts itinerary generation - Fixed device test infrastructure (appxmanifest, PublicAPI, test runner script) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…dmark - PromptBasedSchemaClient middleware converts JSON schema to prompt-based instructions for Phi Silica - Strips markdown code fences from non-streaming responses - Fixed chat bubble alignment on Windows (Grid wrapper for CollectionView items) - Fixed chat scroll-to-end (DispatchDelayed + MakeVisible) - Removed LanguagePreferenceService — language passed as navigation parameter - Added Temperature (0.8-0.9) for creative agents/tips - Fixed WeatherService locale issue (InvariantCulture for coordinates) - Added weather display to LandmarkDetailPage - Map placeholder on Windows (OnPlatform swap) - TravelPlanResult uses short JsonPropertyName to prevent SLM misspelling - ActivityKind enum prompt-enforced (no attribute changes needed) - StreamingResponseHandler: optional chunker (passthrough mode for pre-chunked models) - Added 7 passthrough unit tests for StreamingResponseHandler - Added Bunaken Marine Park (Manado, Indonesia) as new landmark - Fixed ItineraryWorkflow agent instruction examples Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

File-link PromptBasedSchemaClient from the sample app into the device tests project (Windows only). Add PhiSilicaSchemaClient wrapper that chains PromptBasedSchemaClient → PhiSilicaChatClient, and derive PhiSilicaChatClientJsonSchemaTests from the shared base class. Skip the 'without schema' tests since Phi Silica requires prompt-based schema rewriting. Embedding tests remain excluded for Windows. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Revert Versions.props WinAppSDK (1.8.251106002) and WebView2 (1.0.3179.45) to main values so the rest of the repo is unaffected. Override MicrosoftWindowsAppSDKPackageVersion to 2.0.0-experimental6 only in Essentials.AI.csproj and the AI sample csproj — this scopes the experimental dependency to the AI projects without breaking customers or other MAUI libraries. Remove nuget.org from NuGet.config — the experimental package resolves from the existing internal feeds. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…props Move the per-project MicrosoftWindowsAppSDKPackageVersion overrides into a shared Directory.Build.props at src/AI/. All AI projects (library, sample, device tests) pick it up through MSBuild walk-up. The sample no longer has a direct WinAppSDK PackageReference — it receives the dependency transitively through Essentials.AI. Chain: src/AI/samples/Directory.Build.props -> src/AI/Directory.Build.props -> root Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add PhiSilicaChatClientFunctionCallingTests (base class derivation) and PhiSilicaChatClientValidationTests (adapted from Apple tests). Packaged run on Copilot+ PC: 44/44 passed, 0 failed, 0 skipped. FunctionCalling/JsonSchema/Validation tests need longer runtime (each test makes real Phi Silica LLM calls). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mattleibow force-pushed the dev/ai-windows branch 3 times, most recently from 04c4caa to 7e57668 Compare January 19, 2026 20:50

mattleibow changed the title ~~[WIP] Windows AI~~ [Feature] Add Microsoft.Maui.Essentials.AI - Phi Silica Jan 19, 2026

mattleibow changed the title ~~[Feature] Add Microsoft.Maui.Essentials.AI - Phi Silica~~ [Feature] Add Microsoft.Maui.Essentials.AI - Windows AI / Phi Silica Jan 19, 2026

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mattleibow force-pushed the dev/ai-windows branch from f884a51 to fbd619c Compare February 2, 2026 19:48

mattleibow force-pushed the dev/ai-windows branch 2 times, most recently from 0efd5f5 to 583fb81 Compare February 13, 2026 10:19

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mattleibow and others added 8 commits March 26, 2026 04:10

Update LandmarksPage.xaml.cs

65f5ed0

Add StreamingResponseHandler passthrough mode + tests

4c90bf2

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add streaming device tests (DeliversMultipleIncrementalUpdates, Conca…

792cbf8

…tenatedText) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Revert csproj to main (Windows manifest props belong in Windows PR)

e81bcd1

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Use the correct attribute

b342d97

mattleibow force-pushed the dev/ai-windows branch from f7c5eff to 27b87c9 Compare March 26, 2026 02:14

mattleibow changed the base branch from main to dev/ai-sample-improvements March 26, 2026 02:15

mattleibow changed the title ~~[Feature] Add Microsoft.Maui.Essentials.AI - Windows AI / Phi Silica~~ [AI] Windows Copilot Runtime (Phi Silica) support for Essentials.AI Mar 26, 2026

Use DisplayName instead of JsonPropertyName for schema compatibility

47c929b

PromptBasedSchemaClient reads DisplayName for prompt-based JSON schema generation, which works across all platforms including Phi Silica. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mattleibow force-pushed the dev/ai-windows branch from 27b87c9 to 2c34359 Compare March 26, 2026 02:18

mattleibow and others added 5 commits March 26, 2026 04:29

Resolve merge conflicts and restore Windows registrations

717aa7a

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mattleibow force-pushed the dev/ai-windows branch from 868d251 to d9bdbcd Compare March 26, 2026 02:30

mattleibow and others added 3 commits March 26, 2026 09:29

Base automatically changed from dev/ai-sample-improvements to main April 2, 2026 14:09

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[AI] Windows Copilot Runtime (Phi Silica) support for Essentials.AI#33605

[AI] Windows Copilot Runtime (Phi Silica) support for Essentials.AI#33605
mattleibow wants to merge 18 commits intomainfrom
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Summary

New Components

Capabilities

Sample App Changes

Dependencies

Test Coverage

Requirements

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mattleibow commented Jan 19, 2026 •

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