[BUG] Silent exit during idle input phase (~30-60 seconds after last activity)

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
Claude Code silently exits while the user is typing input, approximately 30-60 seconds after the last assistant response. No error message is displayed - the process simply terminates and returns to the shell prompt.

What Should Happen?

Bug Report:

## Environment

• Claude Code version: 2.0.69
• OS: Synology DSM 7.2.2 (Linux 4.4.302+, x86_64, synology_apollolake_218+)
• Node.js: v20.19.5
• Shell: zsh
• Connection: SSH

## Notes

• Reproduced 3+ times in a single session
• SSH connection remains alive (only Claude process exits)
• No OOM or kernel kills in dmesg
• Memory is not an issue (7.5GB available)
• Session can be resumed with /resume

Error Messages/Logs

The debug log (`~/.claude/debug/*.txt`) ends abruptly with no shutdown or error:

  2025-12-13T14:13:26.157Z [DEBUG] executePreToolHooks called for tool: Bash
  2025-12-13T14:13:26.200Z [DEBUG] Getting matching hook commands for PreToolUse with query: Bash
  2025-12-13T14:13:26.200Z [DEBUG] Found 0 hook matchers in settings
  2025-12-13T14:13:26.200Z [DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
  [EOF - no shutdown, no error]

Steps to Reproduce

1. Start claude or claude --debug
2. Have a conversation (send a message, receive response)
3. Wait 30-60 seconds while typing a new message
4. Claude Code exits silently, returning to shell prompt

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.69 (Claude Code)

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Terminal.app (macOS)

Additional Information

connected via SSH