Mention currently open desktop applications from the composer with @

[Abaans]

Problem

In T3 Code Nightly on macOS, I want to point the agent at an application that is already open on my computer. Typing an app name after @ currently gives me file matches rather than a clear application target.

For example, with Chaos Zero Nightmare open, I want to write “use computer control with @chaos Zero Nightmare” and select the running app. The same interaction would be useful for an editor, design application, or other desktop program.

Interaction reference: ChatGPT's mention picker

The reference is the ChatGPT desktop interaction shown in my screenshots: typing @cha lists Chaos Zero Nightmare — Computer use with the running app's icon, separately from a Chaos Zero Nightmare skill result with its own description. Other running apps are also labeled Computer use. The broader picker distinguishes conversations, tabs, files/chats, and pages.

The key behavior I want in T3 is the same clear distinction between a running application target and a similarly named skill or file, within the searchable @ menu. An explicit Computer use label would make it clear which result selects the open app. This describes the visible UI reference, not a claim about ChatGPT's internal implementation. Screenshots are omitted here because they contain unrelated private workspace details.

Proposed interaction

• Include an Open apps group in the composer’s @ picker, searchable by application name, alongside existing mention types.
• Show the app name and icon. Where multiple windows need disambiguation, let the user choose the intended window.
• Insert an app mention chip that identifies the selected application/window and the computer it belongs to.
• Pass that explicit target to the agent so it can use available, authorized computer-use tools rather than guessing which app the user means.
• If the app closes or the window becomes unavailable, report that clearly rather than silently selecting another app.

Scope and permissions

A first version could target running desktop applications on the local Mac. This is an app-selection/context feature, not a request to implement a new computer-control engine or embed every app inside T3.

Selecting an app should not automatically capture its contents, start interacting with it, or grant new OS permissions. Actual observation/control should follow the user's instruction and the existing tool/permission flow. If the active provider has no suitable computer-use tool, make that limitation clear.

For remote agent environments, distinguish the client computer from the execution host. A local app mention should never be interpreted as a similarly named app on a remote machine.

Acceptance example

1. Open a desktop app and start typing its name after @ in T3.
2. Select the running app from an identifiable Open apps result.
3. Send an instruction referencing it.
4. The agent receives the selected target; when supported and authorized, it can address that app through its computer-use tools.
5. Closing the app makes the target unavailable rather than redirecting subsequent actions elsewhere.

Related idea: #22963 proposes explicit mentions for browser tabs. This proposal applies the same discoverable targeting interaction to running native applications.

I would like to contribute toward this feature. Is this direction and initial scope acceptable before implementation?

Prepared with Codex assistance from my workflow and screenshot; no implementation or runtime verification is claimed.