[BUG] Claude Code CLI v2.1.107 exits silently after brief idle — new regression, macOS

Bug Description

Claude Code CLI (v2.1.108, macOS Darwin 25.3.0) silently exits mid-session. This is a NEW regression — started around April 13-14, 2026 and was not happening before.

Key symptom: It happens while actively typing. This is NOT an idle timeout and NOT a permission prompt issue. The session drops to shell with a resume link while the user is in the middle of typing a response.

It also happens:

• While reading Claude's output
• While a permission prompt is waiting
• While background agents/tool calls are running
• After 30-60 seconds of not typing

Approximately 10+ crashes in a single hour-long session, making productive work impossible.

Environment

• Claude Code version: 2.1.108 (auto-updates aggressively, cannot be pinned to older version)
• OS: macOS Darwin 25.3.0
• Shell: zsh
• Terminal: macOS Terminal.app
• Model: Opus 4.6 (1M context)
• MCP servers configured: Atlassian, Slack, Gmail, Notion

Auto-Update Prevents Version Pinning

Attempted to rollback to v2.1.104 by:

1. ln -sf .../2.1.104 .../claude — auto-updater reverts the symlink
2. Deleting 2.1.108 binary — auto-updater re-downloads it
3. Renaming to .disabled — auto-updater ignores it and re-downloads

There is no way to pin to an older version to test if this is a regression in .107/.108 vs .104.

Reproduction

1. Run claude in terminal
2. Start any conversation
3. Session will exit within 1-5 minutes, often while actively typing
4. Output: Resume this session with: claude --resume <id>
5. No error message, no stack trace

Expected Behavior

Session should remain active indefinitely during interactive use.

Impact

Severe. 10+ crashes per hour. Multi-step work is impossible. Each crash requires resume, context recovery, and re-establishing state. An hour of work produces 10 minutes of actual progress.

Related Issues

• #23092 — Desktop app 300s idle timeout
• #24997 — Silent session exits with resume link
• #6691 — Unexpected terminal exit
• #33010 — Unexpected exit on Windows ARM