ToolSearch:optimistic polling loop causes 100% CPU usage

Bug Description

Claude Code sessions running with --dangerously-skip-permissions get stuck in a tight CPU loop due to aggressive polling in the ToolSearch:optimistic feature.

Environment

• Claude Code Version: 2.1.17
• OS: Linux (WSL2 Ubuntu)
• Platform: linux

Symptoms

• Two concurrent Claude Code sessions consuming 100% and 97% CPU each
• Combined ~10GB RAM usage (4.5GB + 5.1GB)
• Debug logs filled with identical messages (84% of log content)

Debug Log Evidence

2026-01-23T10:30:24.836Z [DEBUG] [ToolSearch:optimistic] mode=tst-auto, ENABLE_TOOL_SEARCH=undefined, result=true
2026-01-23T10:30:24.836Z [DEBUG] [ToolSearch:optimistic] mode=tst-auto, ENABLE_TOOL_SEARCH=undefined, result=true
... (63,604 identical lines in one session)

Statistics from affected sessions:

• Session 1: 63,604 ToolSearch spam messages out of 75,281 total lines (84%)
• Session 2: 7,083 ToolSearch spam messages

Root Cause Analysis

The polling loop appears to trigger when:

• ENABLE_TOOL_SEARCH=undefined (not explicitly configured)
• mode=tst-auto (automatic detection mode)
• Running with --dangerously-skip-permissions

The ToolSearch eligibility check runs continuously without rate limiting, causing CPU spin.

Workaround

Setting export ENABLE_TOOL_SEARCH=false in shell environment prevents the issue.

Steps to Reproduce

1. Start Claude Code with claude --dangerously-skip-permissions
2. Work in a project for extended period
3. Observe CPU usage spike to 100%
4. Check debug log at ~/.claude/debug/<session-id>.txt for ToolSearch spam

Expected Behavior

ToolSearch eligibility checks should:

• Have rate limiting / debouncing
• Not poll continuously when result doesn't change
• Cache the result for a reasonable period

Actual Behavior

Continuous tight loop polling consuming 100% CPU per session.