Claude Code Hooks Configuration

Core Expertise

Configure Claude Code lifecycle hooks (SessionStart, SessionEnd, Stop, PreToolUse, PostToolUse) with proper timeout settings to prevent "Hook cancelled" errors during session management.

Hook Types

Hook	Trigger	Default Timeout
SessionStart	When Claude Code session begins	60 seconds
SessionEnd	When session ends or /clear runs	60 seconds
Stop	When assistant stops responding	60 seconds
PreToolUse	Before a tool executes	60 seconds
PostToolUse	After a tool completes	60 seconds

Common Issue: Hook Cancelled Error

SessionEnd hook [bash ~/.claude/session-logger.sh] failed: Hook cancelled

Root cause: Hook execution exceeds the 60-second default timeout.

Solutions (in order of preference):

1. Background subshell - Run slow operations in background, exit immediately
2. Explicit timeout - Add timeout field to hook configuration

Hook Configuration

Location

Hooks are configured in .claude/settings.json:

• User-level: ~/.claude/settings.json
• Project-level: <project>/.claude/settings.json

Structure with Timeout

{
  "hooks": {
    "SessionEnd": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "~/.claude/session-logger.sh",
            "timeout": 120
          }
        ]
      }
    ],
    "SessionStart": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "~/.claude/session-setup.sh",
            "timeout": 180
          }
        ]
      }
    ],
    "Stop": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "~/.claude/stop-hook-git-check.sh",
            "timeout": 30
          }
        ]
      }
    ]
  }
}

Timeout Guidelines

Hook Type	Recommended Timeout	Use Case
SessionStart	120-300s	Tests, linters, dependency checks
SessionEnd	60-120s	Logging, cleanup, state saving
Stop	30-60s	Git status checks, quick validations
PreToolUse	10-30s	Quick validations
PostToolUse	30-60s	Logging, notifications

Fixing Timeout Issues

Recommended: Background Subshell Pattern

The most portable and robust solution is to run slow operations in a background subshell and exit immediately:

#!/bin/bash
# ~/.claude/session-logger.sh
# Exits instantly, work continues in background

(
  # All slow operations go here
  echo "$(date): Session ended" >> ~/.claude/session.log
  curl -s -X POST "https://api.example.com/log" -d "session_end=$(date)"
  # Any other slow work...
) &>/dev/null &

exit 0

Why this works:

• ( ) creates a subshell for the commands
• & runs the subshell in background
• &>/dev/null prevents stdout/stderr from blocking
• exit 0 returns success immediately

Comparison of approaches:

Approach	Portability	Speed	Notes
( ) &	bash, zsh, sh	Instant	Recommended
disown	Bash-only	Instant	Not POSIX
nohup	POSIX	Slight overhead	Overkill for hooks

Alternative: Increase Timeout

If you need synchronous execution, add explicit timeout to settings:

cat ~/.claude/settings.json | jq '.hooks'
# Edit to add "timeout": <seconds> to each hook

Script Optimization Patterns

Optimization	Pattern
Background subshell	( commands ) &>/dev/null &
Fast test modes	--bail=1, -x, --dots
Skip heavy operations	Conditional execution
Parallel execution	Use & and wait

Related: Starship Timeout

If you see:

[WARN] - (starship::utils): Executing command "...node" timed out.

This is a separate starship issue. Fix by adding to ~/.config/starship.toml:

command_timeout = 1000  # 1 second (default is 500ms)

For slow node version detection:

[nodejs]
disabled = false
detect_files = ["package.json"]  # Skip .nvmrc to speed up detection

[command]
command_timeout = 2000  # Increase if still timing out

Agentic Optimizations

Context	Command
View hooks config	cat ~/.claude/settings.json | jq '.hooks'
Test hook script	time bash ~/.claude/session-logger.sh
Find slow operations	bash -x ~/.claude/session-logger.sh 2>&1 | head -50
Check starship config	starship config

Quick Reference

Setting	Location	Default
Hook timeout	.claude/settings.json → hook → timeout	60s
Starship timeout	~/.config/starship.toml → command_timeout	500ms
Node detection	~/.config/starship.toml → [nodejs]	Auto

Error Handling

Error	Cause	Fix
Hook cancelled	Timeout exceeded	Add "timeout": 120
Hook failed	Script error	Check exit code, add error handling
Command not found	Missing script	Verify script path and permissions
Permission denied	Script not executable	chmod +x ~/.claude/script.sh

Best Practices

1. Use background subshell - Wrap slow operations in ( ) &>/dev/null & and exit 0
2. Set explicit timeouts - Add timeout field for hooks requiring synchronous execution
3. Test hook timing - Use time bash ~/.claude/script.sh to measure execution
4. Redirect all output - Use &>/dev/null to prevent blocking on stdout/stderr
5. Apply /hooks menu - Use Claude Code's hook menu to reload settings after changes