[BUG] VS Code extension: renamed sessions revert to the auto-generated title

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?

I'm using the Claude Code VS Code extension 2.1.270 on Windows 11 (also seen on 2.1.269).

When I rename a session, the new name shows for a while, then the session goes back to the auto-generated title. It happens in the session list and on the tab after I reopen the chat. It doesn't happen in every session (one long-running session kept its name), but it happens in most of my recent ones.

The rename is saved. The session .jsonl contains my custom-title record, but an ai-title record gets written again right after it and keeps being rewritten. Counts from my own session files:

• A session started 2026-09-12: 3 custom-title records, 96 ai-title records. It shows the auto-generated title.
• Another session started 2026-09-12: 2 custom-title records, 15 ai-title records. It shows the auto-generated title.
• Sessions from before about 2026-09-10 have near-equal counts (for example 50 custom-title vs 49 ai-title), and renames in those stuck.

2.1.269 fixed "a session rename being replaced by the generated name after a window reload when the session was renamed during a long turn." My renames were made near the start of the session, not during a long turn, and they still revert.

Related issues, both closed: #40787, #46587

What Should Happen?

A renamed session should keep the name I gave it, in the session list and on the tab, including after I reopen the chat or reload the window.

Error Messages/Logs

Steps to Reproduce

1. Open the Claude Code panel in VS Code and start a new session.
2. Send a first message and wait for the reply, so the session gets its auto-generated title.
3. Rename the session.
4. Keep working in it, or close the tab and reopen the session from the session list.
5. The name goes back to the auto-generated title.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown. Renames stuck in sessions started before about 2026-09-10.

Claude Code Version

2.1.270 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

This happens in the Claude Code VS Code extension's chat panel (session list and tabs), not in a terminal. The terminal CLI is also 2.1.270.