GemiKey

GemiKey 概念驗證（PoC），探索並實作 Windows 11「Copilot 鍵」的自訂行為。 微軟官方 Copilot hardware key provider 將實體鍵盤上的 Copilot 鍵重新導向至 Google Gemini（或其他自訂應用程式），使其能出現在 Windows 設定的 App Picker 中。

Project Background

Windows 11 allows users to change the behavior triggered by the "Copilot key" in Settings, through the following path:

Settings > Personalization > Text input > Customize Copilot key on keyboard

However, this menu only lists applications that meet specific specifications. This project aims to understand these specifications and provide an implementation template.

Technical Specifications

To make an application appear in Windows' Copilot key option list, you do not need to modify Windows system files. Instead, the application itself must meet the following three conditions:

1. MSIX Packaging: The application must be packaged in MSIX format (supports Desktop, UWP, WinUI 3, and other frameworks).
2. Manifest Registration: Declare support for the Microsoft Copilot hardware key provider extension in Package.appxmanifest.
3. Digital Signature: The application must be signed; otherwise, Windows will not consider it a valid Copilot key target.

Solution Architecture

For integrating "Gemini," this project adopts the following lightweight strategy:

• Create a lightweight Provider App (e.g., a shell program using WebView2 to open https://gemini.google.com/).
• Register as a Provider according to the specification.
• Display with the name "Gemini" in the system menu.

Developer Guide

1. Package Manifest Configuration

In the application's Package.appxmanifest, you must add uap3:AppExtension, and the Name attribute must be specified as com.microsoft.windows.copilotkeyprovider.

<Package ... xmlns:uap3="[http://schemas.microsoft.com/appx/manifest/uap/windows10/3](http://schemas.microsoft.com/appx/manifest/uap/windows10/3)" ...>
  <Applications>
    <Application ...>
      <Extensions>
        <uap3:Extension Category="windows.appExtension">
          <uap3:AppExtension
            Name="com.microsoft.windows.copilotkeyprovider"
            Id="GeminiKeyProvider"
            DisplayName="Gemini"
            Description="Launch Google Gemini via Copilot Key"
            PublicFolder="Public" />
        </uap3:Extension>
      </Extensions>
    </Application>
  </Applications>
</Package>

• DisplayName: The name displayed in the Windows Settings App Picker (e.g., Gemini).
• Description: Descriptive text for the application.

2. Signing Requirements

The official documentation explicitly states:

"Provider apps must be signed in order to be enabled as a target of the Microsoft Copilot hardware key."

Practical signing strategies:

• Development Phase: You can use a self-signed certificate and install the certificate in "Trusted Root Certification Authorities."
• Release Phase: You need to use an official code signing certificate.

Debugging and Verification

If the application does not appear in the list, you can check the system status and current bindings through the following Registry key.

Registry Path:

HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\BrandedKey

Key Name	Description	Possible Values
BrandedKeyChoiceType	Current key behavior type	Search (Search) `App` (Custom App) `AppEnforcedByPolicy` (Policy Enforced)
AppAumid	Currently bound App ID	Target App's AUMID (Application User Model ID)

Common Failure Reasons:

1. App is not installed or needs to be reinstalled (to trigger system Manifest scanning).
2. App is not properly signed.
3. Extension Name in the Manifest is misspelled.

Project Roadmap and MVP

The current Minimum Viable Product (MVP) goal is to "make Gemini selectable in the Settings page."

Technical Options Evaluation

• WPF + WebView2: ✅ (Currently Adopted) Intuitive, high compatibility, suitable for rapid development.
• WinUI 3 (Windows App SDK): Closer to native Windows 11 UI, but the project architecture is heavier.
• Minimized EXE + MSIX: Only launches the default browser to the URL, with the lowest maintenance cost.

Current Status

An MVP based on WPF + WebView2 has been established:

• Source Code: Projects/gemikey/src/GemiHotkeyProvider.App
• Documentation Guide: Projects/gemikey/docs/provider-app-wpf-webview2.md
• Manifest Template: Projects/gemikey/packaging/copilot-key-provider.extension.xml

References (Microsoft Official)

• Windows Keyboard Shortcuts and Copilot Key Description
• IT Management: Manage Windows Copilot
• Developer Specification: Microsoft Copilot hardware key provider