Bug: Hooks stop executing after ~2.5 hours in session

Bug: Hooks Stop Executing After ~2.5 Hours (Session Lifecycle Bug)

Description

Claude Code hooks execute successfully at session start but silently stop working after approximately 2.5 hours in the same session. No errors are logged - they simply stop firing.

Environment

• OS: Windows 11
• Shell: Git Bash (MINGW64)
• Claude Code Version: Latest (as of 2026-01-02)
• Hooks Config: Valid .claude/hooks.json (2683 bytes, 8 hooks configured)

Reproduction Steps

1. Start a fresh Claude Code session with hooks configured in .claude/hooks.json
2. Verify hooks are working:

``bash
# Perform an Edit operation
# Check C:\Users\{user}\.claude\hooks.log for new entries ✅
``

1. Continue working in the same session for ~2.5 hours
2. Perform another Edit operation that should trigger PreToolUse hook
3. Check hooks.log again

``bash
# Expected: New log entry
# Actual: No new entry ❌ (timestamp doesn't update)
``

Evidence

Session 1 (2026-01-02 afternoon)

• 16:28: Hooks executing normally
• Edit operations triggered PreToolUse hooks
• TodoWrite triggered PostToolUse hooks
• All logged successfully in hooks.log
• 18:48: Hooks stopped firing (gap: ~2.5 hours)

Session 2 (2026-01-02 evening) - Confirmed reproduction

• 16:27-16:28: Hooks executing normally

``
2026-01-02 16:27:59 - standards_validator - INFO - Validating Edit operation
2026-01-02 16:28:05 - instruction_matcher - INFO - SUCCESS: Applied 1 instructions
2026-01-02 16:28:21 - todo_sync - INFO - Todo sync complete
``

• 16:50:47: Last hook entry (suspicious)

``
2026-01-02 16:50:47 - standards_validator - INFO - No stdin data, allowing operation
``
Note: "No stdin data" suggests hook invoked but didn't receive tool use data

• 19:15: Performed Edit operation - NO hook fired
• hooks.log not updated
• Last modified timestamp still 16:50:47
• Gap: 2 hours 25 minutes

Expected Behavior

Hooks should continue executing throughout the entire session, from start to termination.

Actual Behavior

Hooks work correctly at session start, then silently stop after ~2.5 hours with no error messages, warnings, or indication of failure.

Impact

Critical - All hook-based functionality stops mid-session:

• ❌ Code validation hooks stop working
• ❌ Auto-documentation hooks stop working
• ❌ Database sync hooks stop working
• ❌ Custom automation breaks

Users lose all automated quality controls without any warning.

Related Issue: /hooks Command Not Working

Running claude hooks or /hooks does NOT display hook configuration. Instead, it returns an AI-generated response:

I can see you've typed "hooks" - how can I help you with the Claude Family hooks system?

Expected: Display configured hooks from .claude/hooks.json
Actual: AI interprets it as a user message

This suggests Claude Code may not be properly loading/maintaining hook configuration state.

Minimal Test Case

// .claude/hooks.json
{
  "hooks": {
    "PreToolUse": [{
      "hooks": [{
        "type": "command",
        "command": "echo $(date) Hook fired >> C:/temp/hook_test.log",
        "timeout": 5
      }],
      "matcher": "Edit"
    }]
  }
}

1. Start Claude Code
2. Perform Edit → Check hook_test.log (should have timestamp) ✅
3. Wait 2.5+ hours in same session
4. Perform Edit → Check hook_test.log (no new timestamp) ❌

Current Workaround

Restart Claude Code every ~2 hours to re-enable hooks.

Hypothesis

Possible root causes:

1. Event listener detachment - Hook event handlers unbound after timeout/idle
2. Process lifecycle bug - Hook subprocess management fails over time
3. Session state corruption - Hook registration lost after certain time threshold
4. Memory/garbage collection - Hook execution context cleaned up incorrectly

The "No stdin data" log entry at 16:50:47 suggests the hook execution framework may be degrading - hooks are being invoked but not receiving tool use data properly.

Additional Context

• All hook scripts exist and are executable
• hooks.json is valid JSON (verified)
• Hook scripts work when manually invoked
• Same hooks.json works perfectly at session start
• Bug is reproducible across multiple sessions
• No errors in Claude Code console/logs

Files for Reference

If helpful for debugging, I can provide:

• Full hooks.json configuration
• Hook script source code
• Complete hooks.log showing the degradation
• Transcript showing tool use without hook execution

---

This is a critical bug affecting production use of Claude Code hooks. Any guidance on debugging or fixes would be greatly appreciated.