Tab key toggle for think mode not working (v2.0.67)

Description

The Tab key toggle for extended thinking mode is not working. Once thinking mode is enabled, it cannot be disabled via Tab key, even after:

• Restarting Claude Code multiple times (5+ times)
• Rebooting the computer
• Switching models (Opus 4.5 → Sonnet → Opus 4.5)

Environment

• Claude Code version: 2.0.67
• Platform: macOS (Darwin 25.1.0)
• Terminal: Default macOS Terminal

Configuration checked

All settings are correct:

• MAX_THINKING_TOKENS: Not set (empty)
• ~/.claude/settings.json: "alwaysThinkingEnabled": false
• ~/.claude/settings.local.json: No thinking-related settings
• Shell profiles (~/.zshrc, ~/.bashrc, etc.): No THINKING environment variables

Expected behavior

Pressing Tab key should toggle thinking mode on/off as documented in:

• https://docs.anthropic.com/en/docs/claude-code/interactive-mode#keyboard-shortcuts

Actual behavior

• Tab key does not toggle thinking mode
• Thinking mode remains enabled regardless of Tab key presses
• Session logs show "thinkingMetadata":{"level":"high","disabled":false,"triggers":[]}

Steps to reproduce

1. Start Claude Code
2. Enable thinking mode (via Tab or by typing "think")
3. Try to disable thinking mode by pressing Tab
4. Observe that thinking mode remains enabled

Additional context

• The ? help menu shows other keyboard shortcuts (Shift+Tab, Option+Enter) but Tab toggle doesn't respond
• This issue persists across new sessions and computer reboots