[BUG] when renaming a conversation thread, we get this error

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?

As soon as I try to rename a conversation within Claude after /resume, I get this:
"This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason:
Error: ENOENT: no such file or directory, open 'n/a'
at Module.openSync (node:fs:555:18)
at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:9:1210
at oI (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:8:8084)
at Object.appendFileSync (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:9:1139)
at D12 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:1110:3100)
at r81 (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:1111:68)
at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:3839:448
at zA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4672:7)
at file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4672:842
at xA (file:///opt/homebrew/lib/node_modules/@anthropic-ai/claude-code/cli.js:4674:570)"

What Should Happen?

Be able to rename it normally.

Error Messages/Logs

Steps to Reproduce

1. /resume
2. Go down to an unnamed thread with a good chunk of messages/turns, e.g. "<22 messages" image

<img width="1233" height="235" alt="Image" src="https://github.com/user-attachments/assets/963769c1-0cee-4dd2-ad75-2e3adab3ee3b" />

1. Press R to rename.
2. Type the name you want, e.g. "Side Quest: Instance 1"
3. Press Enter.
4. Encounter Error

<img width="1172" height="164" alt="Image" src="https://github.com/user-attachments/assets/267a06c4-172d-4d9a-988c-b9e563f54afc" />

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.76

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_