[BUG] Desktop (Windows): session renamed in the iOS app keeps its old title in the Code sidebar, and the stale title is written back on resume

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

A local Code-tab session in the Claude desktop app on Windows was renamed from the Claude iOS app. The new name does reach the host: the session transcript (~/.claude/projects/<project>/<session>.jsonl) gets custom-title entries with the new name, re-appended after later turns. But the desktop sidebar keeps the original auto-generated title, and get_session / list_sessions (ccd_session_mgmt) return it too, so the session can't be found on the PC by the name set on the phone.

When the desktop app later resumes the session (here: after the app was quit and reopened), it appends a custom-title entry with its own stale title, so the name set on the phone is lost from the transcript as well.

What Should Happen?

A rename made in the iOS app should update the desktop sidebar (and get_session / list_sessions). Resuming a session on the desktop must not overwrite a newer title with the desktop's stored one; the latest rename should win on every surface.

Error Messages/Logs

Session A transcript (UTC):
2026-09-08 16:00  first prompt; custom-title = auto-generated title
2026-09-08 17:34  custom-title = name set in the iOS app (kept through 2026-09-11)
2026-09-13 17:15  desktop app restarted; resume turn with entrypoint "claude-desktop", immediately followed by custom-title = the old auto-generated title

Session B:
2026-09-13 05:46  transcript custom-title = name set in the iOS app
2026-09-13 ~17:30 list_sessions and the desktop sidebar still show the auto-generated title

Steps to Reproduce

1. In the Windows desktop app (Code tab), start a local session and send a first prompt so it gets an auto-generated title ("Title A").
2. Open the session in the Claude iOS app (same account) and rename it to "Title B".
3. On the PC the sidebar still shows "Title A", while the session transcript already contains "customTitle":"Title B".
4. Quit and reopen the desktop app so the session is resumed.
5. The transcript now ends with "customTitle":"Title A"; the name set on the phone is gone.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.266 (bundled with Claude for Windows 1.52386.3)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

• Claude for Windows 1.52386.3 (Microsoft Store), Code tab, with bundled Claude Code 2.1.266. Windows 10 Pro 22H2 (build 19045). Claude iOS app on the same account.
• Version note: the desktop app manages its bundled Claude Code; it runs 2.1.266 while the latest on npm is 2.1.270 at the time of filing.
• Related: #91303 (a mobile rename never reaches a Linux host; here it does reach the transcript, but the desktop never adopts it and later overwrites it), #75343 (desktop and mobile show different names), #86607 and #93018 (the opposite direction), #25090 (a custom name replaced after resume in the CLI).