[BUG] IOT instruction (core dumped) on startup

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?

Claude dumps core on launch, after displaying welcome screen and entering insert mode. This happens every time and I'm now unable to use Claude Code.

What Should Happen?

Successful launch, no core dump.

Error Messages/Logs

➜  smartmail git:(main) ✗ claude
^[[I
╭─── Claude Code v2.1.7 ───────────────────────────────────────────────────────────────────────────────────────────╮
│                                              │ Tips for getting started                                          │
│               Welcome back Tom!              │ Run /init to create a CLAUDE.md file with instructions for Claude │
│                                              │ ───────────────────────────────────────────────────────────────── │
│                    ▐▛███▜▌                   │ Recent activity                                                   │
│                   ▝▜█████▛▘                  │ No recent activity                                                │
│                     ▘▘ ▝▝                    │                                                                   │
│                                              │                                                                   │
│   Opus 4.5 · API Usage Billing · Luna Care   │                                                                   │
│            ~/Documents/smartmail             │                                                                   │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
❯ Try "write a test for recommend.py"
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
  -- INSERT --
[1]    1671163 IOT instruction (core dumped)  claude

Steps to Reproduce

Launch claude in the terminal. claude. or claude --continue

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.7

Claude Code Version

2.1.7

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

➜  ~ claude doctor

 Diagnostics
 └ Currently running: native (2.1.7)
 └ Path: /home/tw/.local/bin/claude
 └ Invoked: /home/tw/.local/share/claude/versions/2.1.7
 └ Config install method: native
 └ Search: OK (bundled)

 Updates
 └ Auto-updates: enabled
 └ Auto-update channel: latest

 Version Locks
 └ No active version locks

 Press Enter to continue…
➜  ~ uname -a
Linux mira 6.17.4-76061704-generic #202510191616~1762410050~22.04~898873a SMP PREEMPT_DYNAMIC Thu N x86_64 x86_64 x86_64 GNU/Linux
➜  ~ lsb_release -a
No LSB modules are available.
Distributor ID:	Pop
Description:	Pop!_OS 22.04 LTS
Release:	22.04
Codename:	jammy