[BUG] FORKING

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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?

2 minute internet interruption on my end caused an active Claude Code desktop session to fork into a new session identity (title changed to "[Name] (fork)", new session reference) rather than reconnecting to the same session once connectivity returned. No messages or work were lost since state persists outside the conversation, but the fork is disruptive it changes the session's identity/address mid-work and could confuse anything tracking that session by name

### What Should Happen?

a brief connectivity drop should reconnect to the same session, not create a new one.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

1. Start a Claude Code desktop session and work in it normally (tool calls, conversation).
2. Lose internet connectivity for approximately 2 minutes (e.g. Wi-Fi/ISP drop), while the LAN connection to other local devices remains unaffected.
3. Internet connectivity returns.
4. Observe: the session's title changes to " (fork)" and it now has a new/different session reference ID, instead of resuming the original session in place. No messages were lost, but the session identity changed mid-conversation with no user action taken.

### Claude Model

Sonnet (default)

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

2.1.233 (Claude Code)

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

_No response_

No implementation file, test, or entry point is named. Start by reproducing the macOS desktop session behavior around a two-minute internet interruption, then trace how connectivity recovery handles the session identity; done means the original title and session reference remain unchanged after reconnection.

Written by the indexing model from the issue text.