v2.1.90: Silent crashes during heavy processing, masked by auto-restart (Windows)

Description

Claude Code v2.1.90 on Windows 11 silently crashes and auto-restarts during heavy processing. There is no error message — the session restarts automatically, losing all conversation context. The user only notices because the header banner repeats and prior conversation history disappears.

Steps to reproduce

1. Start Claude Code (tested in both VS Code integrated terminal and standalone PowerShell)
2. Run /effort max
3. Perform a task that triggers heavy processing — e.g., a large subagent exploration (49k+ tokens) followed by extended thinking, or a skill/tool execution
4. Claude Code crashes mid-operation and silently restarts

Observed behavior

• Session dies during processing (observed during "thinking with max effort" and during tool execution)
• Claude Code auto-restarts without any error message
• The startup header ("Claude Code v2.1.90 / Opus 4.6...") appears again mid-terminal
• All conversation context from the previous session is lost
• In VS Code, repeated crash/restart cycles make the terminal appear to have a "shrinking context window" — each restart is a fresh session with no history, and old crashed sessions scroll off the top

Expected behavior

• Either: sessions should not crash during normal processing
• Or: if a crash occurs, the user should see a clear error message explaining what happened, rather than a silent auto-restart that masks the failure

Environment

• Claude Code v2.1.90
• Windows 11 Home 10.0.26200
• Tested in: VS Code integrated terminal AND standalone PowerShell
• Model: Opus 4.6 with max effort

Screenshots

The startup header appears twice in a single terminal session with no user intervention — the user did not restart or re-prompt. The second header appears after a silent crash during a "thinking with max effort" operation:

● Explore(Explore DrawingML diagram system)
  ▪ Done (17 tool uses · 49.5k tokens · 44s)

● Good — I've got the full picture. Let me look at the existing stick figure code...

· Topsy-turvying… (1m 29s · ↓ 2.0k tokens · thinking with max effort)

>

  esc to interrupt

🟧🟧    Claude Code v2.1.90      ← silent restart, no error shown
🟧🟧  Opus 4.6 with max effort · Claude Max
  🟧🟧    D:\claude\physics

🤖 Generated with Claude Code