Session does not auto-disconnect and cannot reuse an already-open tab/window | session 不会自动断开，且不能复用已打开页签 #279

Problem

There are two related usability problems in the current session model:

1. An existing tab/window cannot be reused in place

bsk session start always creates a new browser window with its own about:blank tab. It cannot attach to the user’s current window or directly reuse an already-open tab.

The current tab list and tab borrow flow does not solve this: borrowing physically moves the user tab into the newly created Agent Window. It is not an in-place shared session, and the user still gets an extra browser window. This makes normal agent work feel like every request opens another window/tab.

2. Sessions are not automatically disconnected or cleaned up

bsk session stop is mandatory for cleanup. If the agent turn is interrupted, the CLI/client exits unexpectedly, the connection is lost, or the agent forgets the stop call, the session and Agent Window remain open. The current idle timeout is only a delayed safety net, not lifecycle-bound cleanup.

Interrupted session start can also leave an orphan Agent Window that is not registered to the caller and cannot be cleaned up through the normal plugin/session path.

From the user’s perspective, multiple old sessions and windows accumulate and must be found and closed manually.

Request

• Support reusing the current browser window and/or an already-open tab without creating a new Agent Window. This could be an owner-scoped session or a tab-group-based session instead of a window-bound session.
• Automatically stop the session when the owning agent/client disconnects, the task turn ends, or the start/operation is cancelled. Cleanup should return borrowed tabs, close agent-created tabs, close the Agent Window when appropriate, and remove the session record.
• Consider an explicit --ephemeral/--auto-stop-on-disconnect mode if automatic cleanup cannot be the default, and recover orphan sessions on the next startup or first CLI call.
• Make session list expose enough ownership/lifecycle information for stale-session diagnosis.

This behavior would remove the need for local session-mapping/reuse workarounds in agent harnesses such as Codex and make multi-session use predictable.

Related

• Feature request: option to open the Agent Window as tabs inside the current window (Arc-friendly) | 支持在当前窗口内以标签页方式打开 Agent Window #243: run session tabs inside the current user window/tab group.
• browserskill is opening up browsers and then leaving them open and doing no work in them! #216: sessions/browser windows left open without doing work.
• [Bug][dsh-plugin] start 未返回时残留无人认领的 Agent Window，DSH 侧任何路径都关不掉它 | unregistered Agent Window orphaned by a non-returning browser_session start #245: interrupted start can orphan an Agent Window.

中文摘要： 当前 bsk session start 总会新建一个 Agent Window，不能直接复用用户当前窗口或已经打开的页签；tab borrow 只是把页签移动进新窗口，仍然会产生额外窗口。另一个问题是 session 依赖显式 session stop，任务中断、连接断开或调用方退出时不会自动清理，容易残留 session 和窗口。希望支持复用现有窗口/页签，并在调用方断开、任务结束或启动取消时自动完成 session 清理和孤儿回收。