ToolSearch/deferred tool loading interrupts keyboard input in terminal

Description

When Claude Code fetches deferred tool schemas (ToolSearch select *), the terminal UI re-render interrupts active keyboard input. Keystrokes are dropped or delayed while the top bar updates with the ToolSearch status.

Steps to Reproduce

1. Configure multiple MCP servers with many deferred tools (e.g., Canva, Gmail, Google Calendar, LinkedIn, PhantomBuster, Tally, WhatsApp — 200+ deferred tools total)
2. Start a Claude Code CLI session
3. Begin typing a message in the Claude Code terminal
4. Observe that when select * appears in the top status bar (deferred tool fetching), typing is interrupted — characters are dropped or input focus is momentarily lost

Expected Behavior

ToolSearch/deferred tool loading should happen in the background without interrupting user keyboard input in the terminal.

Actual Behavior

The terminal UI re-render during ToolSearch causes keystroke loss. The more MCP servers with deferred tools configured, the more frequent the interruptions.

Environment

• OS: Windows 11 Pro 10.0.26300
• Shell: Git Bash
• Terminal: Windows Terminal / PowerShell
• Claude Code: CLI (~/.local/bin/claude.exe)
• MCP servers: 8+ configured (Canva, Fireflies, Gmail, Google Calendar x2, LinkedIn, PhantomBuster, Tally, WhatsApp)
• Deferred tools count: 200+

Workaround

Reducing the number of configured MCP servers decreases the frequency of interruptions, but does not eliminate the issue.