[BUG] Session rename fails with ENOENT: no such file or directory, open 'n/a'

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?

## Description
Attempting to rename a Claude Code session results in a crash with an ENOENT error. The error indicates Claude Code is trying to open a file at path 'n/a', which is an invalid path.

## Steps to Reproduce

1. Start a Claude Code session
2. Attempt to rename the session (command/method used: [please specify how you tried to rename])
3. Error occurs immediately

## Expected Behavior
The session should be renamed successfully without errors.

## Actual Behavior
Claude Code crashes with the following error:

Error: ENOENT: no such file or directory, open 'n/a'
at Module.openSync (node:fs:555:18)
at file:///Users/dejan.dezman/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:9:1210
at oI (file:///Users/dejan.dezman/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:8:8084)
at Object.appendFileSync (file:///Users/dejan.dezman/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:9:1139)
at E12 (file:///Users/dejan.dezman/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1110:3100)
at r81 (file:///Users/dejan.dezman/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1111:68)

The error shows Claude Code is attempting to use 'n/a' as a file path, which is invalid.

## Environment

• OS: macOS 26.2
• Claude Code Version: 2.0.76
• Node.js v25.2.1

## Additional Context
The literal string 'n/a' suggests a configuration value or path variable is not being properly initialized during the session rename operation.

What Should Happen?

Session should be renamed.

Error Messages/Logs

Steps to Reproduce

/resume
R on seceted sesion
entering new name
hitting enter

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_