High CPU usage and memory leak in long-running sessions

Description

Claude Code processes accumulate excessive CPU and memory over ~30 minutes of use, causing significant slowdown. Killing and resuming the session (same conversation context) immediately restores normal performance, which rules out context window size as the cause.

Environment

• Claude Code version: 2.1.29 / 2.1.30
• OS: macOS (Darwin 24.6.0, Apple Silicon)
• Model: opus

Observed behavior

• After ~30 minutes, the CLI becomes noticeably slow
• Process stats on a degraded session:
• 414 minutes of CPU time on a mostly-idle session left running overnight
• 823 MB RSS memory (vs ~360 MB on a fresh session)
• 25-72% CPU while idle (should be near 0%)
• A fresh session with the same resumed conversation runs normally

Steps to reproduce

1. Start a claude session with --claude-in-chrome-mcp enabled
2. Use it normally for ~30 minutes (file reads, edits, bash commands)
3. Observe increasing response latency and high CPU/memory via ps aux
4. Kill the process and claude --resume — performance is normal again with the same context

Notes

• No custom hooks or file watchers configured
• The --claude-in-chrome-mcp child process persists alongside the main process and may be a contributing factor, but this has not been isolated
• The pattern (gradual degradation, fixed by restart) suggests a memory leak or accumulating event listeners/timers in the Node.js process