[BUG] Memory leak from excessive [ToolSearch:optimistic] calls causing session crash

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Description

Claude Code sessions crash due to memory exhaustion after ~8 minutes of use. Debug logs show a pathological number of [ToolSearch:optimistic] calls accumulating - 2,341 calls in an 8-minute session, with bursts of 100+ calls within 2 milliseconds.

Environment

• Claude Code version: 2.1.17
• OS: Linux 6.17.0-8-generic (Ubuntu)
• Terminal: Tilix

Possible Trigger

A MaxFileReadTokenExceededError occurred at 21:54:04 (file with 26,691 tokens). The ToolSearch spam intensified after this, though the error itself was handled gracefully.

What Should Happen?

ToolSearch should not be called on every render cycle or in explosive bursts. Memory usage should remain stable during normal sessions.

Error Messages/Logs

1. **Excessive ToolSearch calls**: 2,341 `[ToolSearch:optimistic]` messages in 8 minutes                                                                                                                      
2. **Burst pattern**: At 21:55:49, over 100 identical calls logged within 2ms:                                                                                                                                
   2026-01-23T21:55:49.847Z [DEBUG] [ToolSearch:optimistic] mode=tst-auto, ENABLE_TOOL_SEARCH=undefined, result=true                                                                                          
   2026-01-23T21:55:49.847Z [DEBUG] [ToolSearch:optimistic] mode=tst-auto, ENABLE_TOOL_SEARCH=undefined, result=true                                                                                          
   ... (repeated 100+ times in same millisecond)                                                                                                                                                              
3. **High write ratio warnings**: Consistent `High write ratio: blit=X, write=Y (75-80% writes)` messages suggesting heavy screen repainting

Steps to Reproduce

1. Start a fresh Claude Code session
2. Perform typical development work (in my case, QEMU kernel testing with Bash commands)
3. Session becomes unresponsive after ~8-10 minutes
4. Requires kill -9 to terminate

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.17

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

a50c148a-da9c-4c91-9bef-527a114741ab.txt