Android: allow T3 Code to be selected as the default digital assistant

[tibodpgames-source]

Problem and use case

I would like to invoke T3 Code through Android's system assistant entry point, similar to how users invoke other digital assistants, instead of finding and opening the app first. The goal is to speak a request to an existing T3 Code project or thread and hear a concise response from the connected agent.

This is an Android system integration request, distinct from adding a microphone button inside an already-open composer.

Proposed scope

• Let the user select T3 Code as the default digital assistant in Android settings.
• Open a focused T3 assistant interface from the device's supported assistant gesture or button.
• Let the user choose a connected environment and project/thread, with a predictable remembered selection.
• Support speaking a prompt and sending it through the existing authenticated connection. Make recording, submission and cancellation clear.
• Provide an optional spoken response or concise completion summary, building on a shared voice implementation where possible.
• Handle unavailable environments and microphone permission failures without silently losing the request.

The smallest useful first step could be default-assistant registration plus reliable launch into T3 Code, followed by the voice workflow. A custom wake word, continuous background listening and replacement of every Gemini device-control feature are outside this initial request.

Android implementation direction

Android exposes the ASSISTANT role to eligible apps. Depending on the intended experience, an implementation can use an assist activity and/or a native VoiceInteractionService with voice interaction sessions. The exact approach and Expo/native-module boundary should be agreed with maintainers rather than assumed here.

Official references:

• https://source.android.com/docs/core/permissions/android-roles
• https://developer.android.com/reference/android/service/voice/VoiceInteractionService

Being the phone's default assistant would not by itself provide Android Auto support; that is a separate integration.

Related work and duplicate check

I searched issues, PRs and Ideas discussions for default/digital assistant integration, VoiceInteractionService, ROLE_ASSISTANT and Android voice support. I did not find a dedicated proposal or PR for this system assistant role.

Related proposals address parts of the voice experience:

• Android: microphone dictation into the composer #13603: Android microphone dictation into the composer.
• Voice calls with a thread: hear what the agent is doing and steer it by voice #22091: voice calls with a thread and spoken steering.
• Hands-free thread dispatch from CarPlay and Siri #18286: CarPlay/Siri hands-free dispatch, with Android Auto mentioned as later work.

Suggested acceptance checks

• T3 Code appears as an eligible digital assistant and can be selected through Android settings.
• The supported assistant entry point invokes T3 Code while another app is foregrounded.
• The selected project/thread is clear before a request is submitted.
• Switching to another default assistant works normally.
• The voice phase covers microphone denial, cancellation, disconnected environments and spoken-response interruption.

Would maintainers support this direction, and should assistant invocation be staged separately from the shared voice work?