RangeError: Maximum call stack size exceeded during idle state (possible concurrent session issue)

Bug Description

RangeError: Maximum call stack size exceeded occurs during normal operation, even when Claude Code is idle/waiting for user input.

Environment

• Platform: Windows
• Claude Code: CLI (npm installed)
• Possible trigger: Two Claude Code sessions running in the same project directory

Reproduction

1. Open Claude Code session in a project directory
2. Open a second Claude Code session in the same directory
3. Work normally in one session while the other is idle
4. Stack overflow occurs in the idle session

Error Output

RangeError: Maximum call stack size exceeded

Exception in PromiseRejectCallback:
file:///C:/Users/scott/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3437

(Full minified stack trace available - occurs in tool execution/message processing pipeline)

Frequency

Occurred twice in a single session while Claude Code was waiting for user input.

Notes

• No specific user action triggered the error
• Session was idle at time of crash
• Correlation with concurrent sessions is suspected but not confirmed