FieldCure.AssistStudio.Controls.WinUI 0.4.0

FieldLab AssistStudio

AI Chat Controls for WinUI 3 — Bring Your Own Key, pick any provider.

Features

• BYOK (Bring Your Own Key) — Users supply their own API keys. No proxy, no middleman.
• Multi-Provider — Claude, OpenAI, Gemini, and Ollama out of the box. Implement IAiProvider to add your own.
• Streaming — Real-time token-by-token responses via IAsyncEnumerable<string>.
• Vision & Documents — Attach images (PNG, JPG, WebP, …), PDFs, and DOCX files to any conversation.
• Token Tracking — Input/output token counts exposed after every request.
• Re-templatable WinUI 3 Controls — ChatPanel, InputContainer, AttachmentPreviewBar, and ToolApprovalPanel are TemplatedControls with no app dependency. Override Generic.xaml to fully customize the UI.
• Profiles & Presets — Save provider configurations as presets; switch system prompts with profiles.
• Conversation Persistence — Save and load conversations in .astx (JSON) format.
• Localization — Built-in en-US and ko-KR resource strings.
• Tool / Function Calling — Define tools with IAssistTool and let providers invoke them. Tools that require confirmation show an inline ToolApprovalPanel for user approval before execution.

Screenshots

Empty State	Tool Approval

Architecture

┌─────────────────────────────────────────────────┐
│  AssistStudio (Demo App)                        │
│  WinUI 3 desktop app — showcases all controls   │
├─────────────────────────────────────────────────┤
│  AssistStudio.Controls        ← NuGet package   │
│  ChatPanel · InputContainer · ToolApprovalPanel │
│  WebView2 rendering · Themes · Localization     │
├─────────────────────────────────────────────────┤
│  AssistStudio.Core            ← NuGet package   │
│  IAiProvider · IAssistTool · Models · Helpers   │
│  Claude │ OpenAI │ Gemini │ Ollama providers    │
└─────────────────────────────────────────────────┘

Core is platform-agnostic (net8.0). It has no Windows-specific dependencies — you can reference it from a console app, a server, or any .NET project.

Quick Start

1. Install packages

dotnet add package FieldCure.AssistStudio.Core
dotnet add package FieldCure.AssistStudio.Controls.WinUI

2. Create a provider and wire up the control

using FieldCure.AssistStudio.Providers;

// Pick a provider — API key comes from the user
var provider = new ClaudeProvider(apiKey: "sk-ant-...", modelId: "claude-sonnet-4-20250514");

<Page xmlns:assist="using:FieldCure.AssistStudio.Controls">

    <assist:ChatPanel x:Name="Chat"
                      Placeholder="Ask anything..."
                      Theme="System" />
</Page>

// Code-behind
Chat.Provider = provider;

That's it — you have a fully functional AI chat with streaming, Markdown rendering, and syntax highlighting.

Providers

Supported providers

OpenAI provider works with any OpenAI-compatible API (Groq, Azure OpenAI, etc.) by setting a custom baseUrl.

Implementing a custom provider

Implement IAiProvider to integrate any AI service:

using FieldCure.AssistStudio.Models;
using FieldCure.AssistStudio.Providers;

public class MyCustomProvider : IAiProvider
{
    public string ProviderName => "MyService";
    public string ModelId => "my-model-v1";
    public TokenUsage? LastUsage { get; private set; }
    public bool IsTruncated { get; private set; }
    public string? LastRequestBody { get; private set; }
    public string? LastRawResponse { get; private set; }

    public async Task<AiResponse> CompleteAsync(AiRequest request, CancellationToken ct = default)
    {
        // Call your API, return an AiResponse
        throw new NotImplementedException();
    }

    public async IAsyncEnumerable<string> StreamAsync(
        AiRequest request,
        [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken ct = default)
    {
        // Yield tokens as they arrive
        yield return "Hello ";
        yield return "from MyService!";
    }

    public Task<IReadOnlyList<AiModel>> ListModelsAsync(CancellationToken ct = default)
        => Task.FromResult<IReadOnlyList<AiModel>>(
            [new AiModel("my-model-v1", "My Model", "myservice")]);

    public Task<ConnectionInfo> ValidateConnectionAsync(CancellationToken ct = default)
        => Task.FromResult(new ConnectionInfo(true, null, null, null));
}

Then assign it to a ChatPanel:

Chat.Provider = new MyCustomProvider();

Controls

All controls are TemplatedControls defined in Generic.xaml. They carry no app-level dependency — reference the NuGet package and use them in any WinUI 3 project.

ChatPanel

The main control. Provides a complete chat experience: message list (WebView2), input area, streaming, attachments, presets, and profiles.

<assist:ChatPanel Provider="{x:Bind ViewModel.Provider, Mode=OneWay}"
                  SystemPrompt="You are a helpful assistant."
                  Theme="Dark"
                  Placeholder="Type a message..."
                  AvailablePresets="{x:Bind ViewModel.Presets}"
                  SelectedPreset="{x:Bind ViewModel.CurrentPreset, Mode=TwoWay}" />

Key dependency properties: Provider, SystemPrompt, Theme, Placeholder, AvailablePresets, SelectedPreset, AvailableProfiles, SelectedProfile, MessageFontSize, ShowTitleBar

Events: MessageSent, PresetChanged, FilesDropped, TitleBarRequested

InputContainer

The chat input area — text box, attach button, preset/profile selectors. Used internally by ChatPanel, but can be placed standalone.

AttachmentPreviewBar

Horizontal scrollable bar showing thumbnails of attached files before sending.

ToolApprovalPanel

Inline confirmation panel shown when a tool with RequiresConfirmation = true is invoked. Displays the tool name, an expandable JSON arguments preview, and Allow/Reject buttons. Replaces InputContainer during confirmation and restores it after.

Re-templating

Override the default template in your app's resources:

<Style TargetType="assist:ChatPanel" BasedOn="{StaticResource DefaultChatPanelStyle}">
    
</Style>

Configuration

Provider presets

var preset = new ProviderPreset
{
    Name = "Claude Sonnet",
    ProviderType = "Claude",
    ApiKey = "sk-ant-...",
    ModelId = "claude-sonnet-4-20250514",
    Temperature = 0.7,
    MaxTokens = 4096,
    StreamingEnabled = true
};

Profiles

Profiles pair a system prompt with optional provider/model preferences and tool selections:

var profile = new Profile
{
    Name = "Task Planner",
    Text = "You are a task planner that breaks down complex requests into steps and executes them using available tools.",
    ToolNames = ["search_files", "read_file", "write_file", "run_command"]
};

Requirements

Contributing

Contributions are welcome! Please open an issue first to discuss what you'd like to change.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes
4. Push to the branch and open a Pull Request

License

MIT — Copyright (c) 2026 FieldCure Co., Ltd.