Desktop (Windows): code block Run opens a new terminal tab instead of the existing terminal with an ssh session

Summary

Claude desktop (Windows), Code tab: pressing Run on a ``bash code block opens a **new terminal tab** instead of writing the command into the session's existing terminal, where an interactive ssh` session is open. Until the 2026-09-14 update Run always wrote into the existing terminal.

Environment

• Claude desktop 1.52386.6.0 (MSIX), Windows 11 Pro 10.0.26200
• Claude Code 2.1.270 (updated from 2.1.266 on 2026-09-14)

Steps to reproduce

1. Open a Code session and its terminal panel (terminal 1).
2. In terminal 1 start an interactive ssh <host> session.
3. In the chat, press Run on any ```bash code block.

Expected

The command is written into terminal 1 (the ssh session), as before the update.

Actual

A new terminal tab is spawned and the command runs locally in PowerShell. main.log shows a new PTY per click:

2026-09-14 13:10:44 LocalSessions.startShellPty: sessionId=local_…::1
2026-09-14 13:21:39 LocalSessions.startShellPty: sessionId=local_…::2
2026-09-14 13:21:45 LocalSessions.startShellPty: sessionId=local_…::3
2026-09-14 13:24:02 LocalSessions.startShellPty: sessionId=local_…::4
2026-09-14 13:30:12 LocalSessions.startShellPty: sessionId=local_…::5
2026-09-14 14:07:04 LocalSessions.startShellPty: sessionId=local_…::8

• Right after a full app restart (tray → Exit), Run writes into terminal 1 again (13:56).
• After ~5–10 minutes without terminal output, Run spawns a new tab again (14:07). No session switch happened in between (no setFocusedSession in the log).
• Pressing Enter in terminal 1 before Run (to produce output) does not help.
• In the prior month such extra tabs appeared 3 times; on 2026-09-14 — 8 times.

Notes from the local bundle

In app/resources/ion-dist/assets/v1/c11959232-*.js, run writes directly only when isPrimaryTarget && ptyReady, where ptyReady = <shell_pty_data seen for the session> && !<lazy module failed>; on Windows getBusyShellPtyKeys returns {busy: [], probed: false}. The live interface is loaded from assets-proxy.anthropic.com and may differ from the local copy. Something resets the ready state after a period of inactivity.

Impact

Running remote commands via Run inside an open ssh session is no longer possible; every click spawns a local terminal that has to be closed.