[BUG] Terminal becomes blank/unresponsive after spawning multiple subagents and minimizing window (macOS/Kitty)

[BUG] Terminal becomes blank/unresponsive after spawning multiple subagents and minimizing window (macOS/Kitty)

Environment

• Platform: npm local
• Claude CLI version: 2.1.29
• Operating System: macOS 26.2 (Darwin 25.2.0) ARM64 (Apple Silicon)
• Terminal: Kitty

Bug Description

When running Claude Code with multiple subagents spawned in parallel, if I minimize the terminal or switch away from it for a period of time, when I return the terminal shows a completely blank screen. The terminal becomes completely unresponsive:

• Cannot type any input
• Ctrl+C does not work
• Escape does not work
• No visible output or cursor

The only recovery is to force-close the entire Kitty terminal application.

Steps to Reproduce

1. Start Claude Code in Kitty terminal
2. Run a task that spawns multiple subagents in parallel (e.g., orchestrator mode with 3+ parallel task-builders)
3. Minimize the terminal window or switch to another application
4. Wait some time (anywhere from a few minutes to 30+ minutes)
5. Return to the Kitty terminal

Expected Behavior

The terminal should show the current state of Claude Code with any recent output, and be responsive to input.

Actual Behavior

• Terminal is completely blank (black/empty screen)
• No response to any keyboard input
• Cannot interrupt with Ctrl+C or Escape
• Must force-quit Kitty to recover

Additional Context

This is intermittent - sometimes running many parallel subagents works perfectly fine. I've had 20 simultaneous subagents complete a complex Three.js website build in 15 minutes without issue. Other times, the same pattern triggers the freeze.

The blank screen behavior suggests a terminal rendering bug that may be separate from the GC/freeze issues reported in other issues. The trigger specifically seems to involve:

1. Multiple parallel subagents
2. Window being minimized or backgrounded
3. Returning to the window after some time

This may be related to terminal escape sequences or PTY buffer issues when the terminal isn't actively rendering.

Related Issues

• #5682 - Claude code freezing when launching multiple writing subagents
• #8061 - SubAgents Expansions Broken (breaks terminal in Cursor)
• #19415 - Parallel bash tool execution causes process freeze
• #19344 - GC death spiral causes process freeze

Workaround

None currently - must force-quit terminal and use claude --continue to resume session.