[Feature]: Prompt for confirmation before closing window when agent tasks are running

[screen-gd]

Summary

Clicking the window close button (X) immediately terminates the desktop app without a confirmation prompt. If an agent run is active, the app exits immediately and aborts the ongoing work.

Problem

Accidental clicks on the close button kill running agent sessions in Codex and other providers. This causes the agent to stop the work and requires starting it again.

Proposed solution

Show a confirmation dialog before closing the window when an agent task is active:

• Warn that an active agent run will be stopped.
• Provide options to cancel or proceed with closing.
• Optionally add a setting to toggle close confirmation behavior.

Environment

• OS: Windows 11
• App: T3 Code Nightly (v0.0.41-nightly.20260908.1387)

[juliusmarminge]

Thanks for the report — this is a real Windows gap, and it is not a duplicate of the other open quit/close issues.

What happens today

On Windows/Linux, closing the last window quits the desktop host (window-all-closed → app.quit()). The window close handler only persists bounds; there is no confirmation. Quit then stops every backend in the pool, so an in-progress Codex/other-provider turn is aborted.

The existing Settings → General → Confirmations → Quit shortcut (confirmQuit: hold / double-press / direct) applies only to Ctrl/Cmd+Q. Application-menu Quit is documented as immediate. None of that covers the title-bar X.

On macOS, closing the window does not quit the app, so this is mostly a Windows (and Linux) chrome problem.

Related, not the same

• Windows desktop app abruptly quits on closing last tab with Ctrl+W; align behavior with macOS via System Tray #10161 — Ctrl+W / last tab quits on Windows; tray vs macOS
• [Bug]: Cmd + Q has weird closing behavior #9259 — Cmd+Q hold quirk
• [Bug]: Holding Cmd+Q can silently hang the app instead of quitting #7598 — quit hang
• feat(desktop): Chrome-style hold-to-quit #5508 / feat(desktop): add configurable quit shortcut confirmation #9076 — shipped shortcut confirmation (not window close)
• fix(desktop): confirm before quitting the app #5361 (closed) — always-on Quit dialog; closed as path-inconsistent extra friction
• feat(desktop): keep Windows host in system tray #7493 (open) — Windows close-to-tray; would keep agents alive on X without a prompt

No open PR implements “confirm close only when an agent is running.”

Product choice

We should pick one Windows close story rather than stacking both:

1. Close-to-tray (feat(desktop): keep Windows host in system tray #7493 / Windows desktop app abruptly quits on closing last tab with Ctrl+W; align behavior with macOS via System Tray #10161): X hides; work keeps running.
2. Confirm only while a turn is running: intercept close, ask the renderer/server, native Cancel/Close; idle close stays one click.
3. Confirm on every X — likely a non-starter given fix(desktop): confirm before quitting the app #5361.

A new confirmQuit-style toggle is optional; that setting is shortcut-only today. If we do (2), File → Quit should be decided in the same change so quit is not path-dependent again.

Classifying as an enhancement (current behavior is intentional). Leaving unaccepted until we choose tray vs confirm-when-busy.