Creating Claude Code Hooks

{
  "hooks": {
    "PostToolUse": [{
      "matcher": "Write|Edit",
      "hooks": [{
        "type": "command",
        "command": "${CLAUDE_PLUGIN_ROOT}/scripts/format.sh",
        "timeout": 5000
      }]
    }]
  }
}

{
  "hooks": {
    "PreToolUse": [{
      "matcher": "Write|Edit|Read",
      "hooks": [{
        "type": "command",
        "command": "${CLAUDE_PLUGIN_ROOT}/scripts/block-sensitive.sh"
      }]
    }]
  }
}

{
  "hooks": {
    "Stop": [{
      "matcher": "*",
      "hooks": [{
        "type": "prompt",
        "prompt": "Before finishing, verify: 1) All tests pass 2) No linting errors 3) Types check. If any issues, list them."
      }]
    }]
  }
}

{
  "hooks": {
    "SessionStart": [{
      "matcher": "*",
      "hooks": [{
        "type": "command",
        "command": "${CLAUDE_PLUGIN_ROOT}/scripts/load-context.sh",
        "once": true
      }]
    }]
  }
}

{
  "hooks": {
    "PreToolUse": [{
      "matcher": "Write",
      "hooks": [{
        "type": "command",
        "command": "./validate-before.sh"
      }]
    }],
    "PostToolUse": [{
      "matcher": "Write",
      "hooks": [{
        "type": "command",
        "command": "./verify-after.sh"
      }]
    }]
  }
}

# Check dependencies exist
if ! command -v jq &> /dev/null; then
  echo "jq not installed, skipping" >&2
  exit 0
fi

# Validate input
FILE=$(echo "$INPUT" | jq -r '.input.file_path // empty')
if [[ -z "$FILE" ]]; then
  echo "No file path provided" >&2
  exit 1
fi

#!/bin/bash
#!/usr/bin/env node
#!/usr/bin/env python3

BLOCKED=(".env" ".env.*" "*.pem" "*.key")
for pattern in "${BLOCKED[@]}"; do
  case "$FILE" in
    $pattern)
      echo "Blocked: $FILE is sensitive" >&2
      exit 2
      ;;
  esac
done

# WRONG - breaks on spaces
prettier --write $FILE

# RIGHT - handles spaces
prettier --write "$FILE"

LOG_FILE=~/.claude-hooks/debug.log

# Log to file
echo "[$(date)] Processing $FILE" >> "$LOG_FILE"

# Log to stderr (shows in transcript)
echo "Hook running..." >&2

my-hook/
├── prpm.json          # Package manifest
├── HOOK.md            # Hook documentation
└── hook-script.sh     # Hook executable

{
  "name": "@username/hook-name",
  "version": "1.0.0",
  "description": "Brief description shown in search",
  "author": "Your Name",
  "format": "claude",
  "subtype": "hook",
  "tags": ["automation", "security", "formatting"],
  "main": "HOOK.md"
}

---
name: session-logger
description: Logs session start/end times for tracking
event: SessionStart
language: bash
hookType: hook
---

# Session Logger Hook

Logs Claude Code session activity for tracking and debugging.

## Installation

This hook will be installed to `.claude/hooks/session-start`.

## Behavior

- Logs session start time to `~/.claude/session.log`
- Displays environment status
- Runs silent dependency checks

## Requirements

- bash 4.0+
- write access to `~/.claude/`

## Source Code

\`\`\`bash
#!/bin/bash
echo "Session started at $(date)" >> ~/.claude/session.log
echo "Environment ready"
exit 0
\`\`\`

# Test locally first
prpm test

# Publish to registry
prpm publish

# Version bumps
prpm publish patch  # 1.0.0 -> 1.0.1
prpm publish minor  # 1.0.0 -> 1.1.0
prpm publish major  # 1.0.0 -> 2.0.0

# Parse JSON safely
INPUT=$(cat)
if ! FILE=$(echo "$INPUT" | jq -r '.input.file_path // empty' 2>&1); then
  echo "JSON parse failed" >&2
  exit 1
fi

# Validate field exists
[[ -n "$FILE" ]] || exit 1

# Prevent directory traversal
if [[ "$FILE" == *".."* ]]; then
  echo "Path traversal detected" >&2
  exit 2
fi

# Keep in project directory
if [[ "$FILE" != "$CLAUDE_PROJECT_DIR"* ]]; then
  echo "File outside project" >&2
  exit 2
fi