File Size Warning Monitor

Hook Content

The main content for this hook.

post-tool-use.json

json

{
  "hookConfig": {
    "hooks": {
      "postToolUse": {
        "script": "./.claude/hooks/file-size-warning-monitor.sh",
        "matchers": [
          "write",
          "edit"
        ]
      }
    }
  },
  "scriptContent": "#!/usr/bin/env bash\n\n# Read the tool input from stdin\nINPUT=$(cat)\nTOOL_NAME=$(echo \"$INPUT\" | jq -r '.tool_name')\nFILE_PATH=$(echo \"$INPUT\" | jq -r '.tool_input.file_path // .tool_input.path // \"\"')\n\nif [ -z \"$FILE_PATH\" ]; then\n  exit 0\nfi\n\n# Check if file exists and is a regular file\nif [ ! -f \"$FILE_PATH\" ]; then\n  exit 0\nfi\n\necho \"📏 Checking file size for: $(basename \"$FILE_PATH\")\" >&2\n\n# Get file size in bytes (cross-platform)\nget_file_size() {\n  local file=\"$1\"\n  \n  # Try different stat formats for cross-platform compatibility\n  if stat -f%z \"$file\" 2>/dev/null; then\n    # macOS/BSD\n    return 0\n  elif stat -c%s \"$file\" 2>/dev/null; then\n    # Linux/GNU\n    return 0\n  elif [ -f \"$file\" ]; then\n    # Fallback: use wc for text files (less accurate for binary)\n    wc -c < \"$file\" 2>/dev/null || echo \"0\"\n  else\n    echo \"0\"\n  fi\n}\n\n# Convert bytes to human-readable format\nformat_size() {\n  local bytes=\"$1\"\n  \n  if [ \"$bytes\" -lt 1024 ]; then\n    echo \"${bytes}B\"\n  elif [ \"$bytes\" -lt 1048576 ]; then\n    echo \"$((bytes / 1024))KB\"\n  elif [ \"$bytes\" -lt 1073741824 ]; then\n    echo \"$((bytes / 1048576))MB\"\n  else\n    echo \"$((bytes / 1073741824))GB\"\n  fi\n}\n\n# Get file extension\nget_file_extension() {\n  local file=\"$1\"\n  echo \"${file##*.}\" | tr '[:upper:]' '[:lower:]'\n}\n\n# Define file type categories and their thresholds\nget_size_threshold() {\n  local extension=\"$1\"\n  \n  case \"$extension\" in\n    # Source code files - should be relatively small\n    js|jsx|ts|tsx|py|rb|go|rs|java|cpp|c|h|hpp|php|cs)\n      echo \"500000\"  # 500KB\n      ;;\n    # Data/config files\n    json|xml|yaml|yml|toml|ini|conf)\n      echo \"1048576\"  # 1MB\n      ;;\n    # Documentation\n    md|txt|rst|org)\n      echo \"1048576\"  # 1MB\n      ;;\n    # Images\n    jpg|jpeg|png|gif|bmp|webp|svg)\n      echo \"2097152\"  # 2MB\n      ;;\n    # Videos\n    mp4|avi|mov|wmv|flv|webm|mkv)\n      echo \"52428800\"  # 50MB\n      ;;\n    # Audio\n    mp3|wav|flac|aac|ogg)\n      echo \"10485760\"  # 10MB\n      ;;\n    # Archives\n    zip|tar|gz|bz2|xz|7z|rar)\n      echo \"20971520\"  # 20MB\n      ;;\n    # Binary executables\n    exe|bin|app|dmg|deb|rpm)\n      echo \"104857600\"  # 100MB\n      ;;\n    # Default for unknown file types\n    *)\n      echo \"5242880\"  # 5MB\n      ;;\n  esac\n}\n\n# Get optimization suggestions for file type\nget_optimization_suggestions() {\n  local extension=\"$1\"\n  local size_mb=\"$2\"\n  \n  case \"$extension\" in\n    js|jsx|ts|tsx)\n      echo \"Consider code splitting, tree shaking, or minification\"\n      ;;\n    json)\n      echo \"Consider JSON streaming, compression, or breaking into smaller files\"\n      ;;\n    jpg|jpeg)\n      echo \"Consider JPEG optimization, WebP format, or progressive JPEG\"\n      ;;\n    png)\n      echo \"Consider PNG optimization, WebP format, or SVG for simple graphics\"\n      ;;\n    gif)\n      echo \"Consider converting to WebP or MP4 for better compression\"\n      ;;\n    svg)\n      echo \"Consider SVG optimization tools to remove unnecessary elements\"\n      ;;\n    mp4|mov)\n      echo \"Consider video compression, lower resolution, or streaming\"\n      ;;\n    pdf)\n      echo \"Consider PDF compression or splitting into smaller documents\"\n      ;;\n    zip|tar|gz)\n      echo \"Archive seems large - verify contents are necessary\"\n      ;;\n    md|txt)\n      echo \"Consider breaking into smaller documents or using external storage\"\n      ;;\n    *)\n      echo \"Consider file compression or alternative storage solutions\"\n      ;;\n  esac\n}\n\n# Get file size\nSIZE_BYTES=$(get_file_size \"$FILE_PATH\")\nSIZE_HUMAN=$(format_size \"$SIZE_BYTES\")\nSIZE_MB=$((SIZE_BYTES / 1048576))\nSIZE_KB=$((SIZE_BYTES / 1024))\n\n# Get file info\nFILE_EXTENSION=$(get_file_extension \"$FILE_PATH\")\nFILE_NAME=$(basename \"$FILE_PATH\")\nTHRESHOLD_BYTES=$(get_size_threshold \"$FILE_EXTENSION\")\nTHRESHOLD_HUMAN=$(format_size \"$THRESHOLD_BYTES\")\n\necho \"📊 File: $FILE_NAME ($SIZE_HUMAN)\" >&2\n\n# Check if file exceeds threshold\nif [ \"$SIZE_BYTES\" -gt \"$THRESHOLD_BYTES\" ]; then\n  echo \"⚠️ SIZE WARNING: File exceeds recommended threshold for .$FILE_EXTENSION files\" >&2\n  echo \"   Current: $SIZE_HUMAN | Recommended: < $THRESHOLD_HUMAN\" >&2\n  \n  # Provide optimization suggestions\n  SUGGESTION=$(get_optimization_suggestions \"$FILE_EXTENSION\" \"$SIZE_MB\")\n  echo \"💡 Suggestion: $SUGGESTION\" >&2\n  \n  # Specific warnings for very large files\n  if [ \"$SIZE_MB\" -gt 50 ]; then\n    echo \"🚨 VERY LARGE FILE: This file may cause performance issues\" >&2\n    echo \"   Consider using Git LFS for files over 50MB\" >&2\n  elif [ \"$SIZE_MB\" -gt 10 ]; then\n    echo \"⚠️ LARGE FILE: May impact repository performance\" >&2\n  fi\n  \nelse\n  echo \"✅ File size within acceptable range ($THRESHOLD_HUMAN threshold)\" >&2\nfi\n\n# Special checks for specific file types\ncase \"$FILE_EXTENSION\" in\n  js|jsx|ts|tsx)\n    if [ \"$SIZE_KB\" -gt 100 ]; then\n      echo \"📦 JavaScript bundle size check: Consider code splitting for better performance\" >&2\n    fi\n    ;;\n  json)\n    if [ \"$SIZE_KB\" -gt 500 ]; then\n      echo \"📄 Large JSON detected: Consider pagination or streaming for API responses\" >&2\n    fi\n    ;;\n  jpg|jpeg|png|gif|webp)\n    if [ \"$SIZE_KB\" -gt 500 ]; then\n      echo \"🖼️ Image optimization: Large images impact web performance\" >&2\n      if command -v identify &> /dev/null; then\n        DIMENSIONS=$(identify -format '%wx%h' \"$FILE_PATH\" 2>/dev/null || echo \"unknown\")\n        echo \"   Dimensions: $DIMENSIONS\" >&2\n      fi\n    fi\n    ;;\n  css|scss|sass)\n    if [ \"$SIZE_KB\" -gt 200 ]; then\n      echo \"🎨 CSS size check: Consider removing unused styles or splitting stylesheets\" >&2\n    fi\n    ;;\nesac\n\n# Check if file is in git repository\nif command -v git &> /dev/null && git rev-parse --git-dir > /dev/null 2>&1; then\n  # Check if file is tracked by git\n  if git ls-files --error-unmatch \"$FILE_PATH\" &> /dev/null; then\n    echo \"🔄 Git repository impact:\" >&2\n    \n    # Check if file has grown significantly\n    if git log --oneline -n 1 -- \"$FILE_PATH\" &> /dev/null; then\n      # File has history, check previous size\n      PREV_SIZE=$(git show HEAD:\"$FILE_PATH\" 2>/dev/null | wc -c | xargs || echo \"0\")\n      if [ \"$PREV_SIZE\" -gt 0 ]; then\n        PREV_SIZE_HUMAN=$(format_size \"$PREV_SIZE\")\n        SIZE_DIFF=$((SIZE_BYTES - PREV_SIZE))\n        \n        if [ \"$SIZE_DIFF\" -gt 0 ]; then\n          DIFF_HUMAN=$(format_size \"$SIZE_DIFF\")\n          PERCENT_INCREASE=$((SIZE_DIFF * 100 / PREV_SIZE))\n          echo \"   Size change: +$DIFF_HUMAN (+$PERCENT_INCREASE%) from previous version\" >&2\n          \n          if [ \"$PERCENT_INCREASE\" -gt 100 ]; then\n            echo \"   📈 Significant size increase detected\" >&2\n          fi\n        fi\n      fi\n    fi\n    \n    # Suggest Git LFS for large files\n    if [ \"$SIZE_MB\" -gt 10 ]; then\n      echo \"   💡 Consider using Git LFS for this large file\" >&2\n      if [ -f \".gitattributes\" ]; then\n        if ! grep -q \"*.$FILE_EXTENSION.*lfs\" \".gitattributes\" 2>/dev/null; then\n          echo \"   Add to .gitattributes: *.$FILE_EXTENSION filter=lfs diff=lfs merge=lfs -text\" >&2\n        fi\n      else\n        echo \"   Create .gitattributes with: *.$FILE_EXTENSION filter=lfs diff=lfs merge=lfs -text\" >&2\n      fi\n    fi\n  fi\nfi\n\n# Overall performance impact assessment\necho \"\" >&2\necho \"📋 Performance Impact Assessment:\" >&2\n\nif [ \"$SIZE_MB\" -gt 50 ]; then\n  echo \"  🔴 High Impact: File may cause significant performance issues\" >&2\nelif [ \"$SIZE_MB\" -gt 10 ]; then\n  echo \"  🟡 Medium Impact: File may cause minor performance issues\" >&2\nelif [ \"$SIZE_KB\" -gt 500 ]; then\n  echo \"  🟢 Low Impact: File size is acceptable but monitor growth\" >&2\nelse\n  echo \"  ✅ Minimal Impact: File size is optimal\" >&2\nfi\n\necho \"\" >&2\necho \"💡 File Size Best Practices:\" >&2\necho \"   • Keep source code files under 500KB\" >&2\necho \"   • Optimize images before committing\" >&2\necho \"   • Use Git LFS for files over 10MB\" >&2\necho \"   • Consider file compression for large data files\" >&2\n\nexit 0"
}

Features

Key capabilities and functionality

Real-time file size monitoring during write/edit operations
Configurable size thresholds for different file types
File type-specific recommendations (images, JSON, code, etc.)
Performance impact warnings for large files
Git repository size impact analysis
Compression suggestions for media files
Size comparison with previous versions
Multi-platform file size detection (macOS, Linux, Windows)

Installation

Setup instructions and requirements

Claude Code Setup

Create hooks directory: mkdir -p .claude/hooks
Create hook script: .claude/hooks/file-size-warning-monitor.sh
Add hook configuration to your Claude Code config
Make script executable: chmod +x .claude/hooks/file-size-warning-monitor.sh
Restart Claude Code to activate the hook

Configuration Paths

project

.claude/hooks/

user

~/.claude/hooks/

Requirements

Claude Code CLI
Bash shell
Hook-specific dependencies (e.g., jq, prettier)

Hook Configuration

Hook setup and script content

post-tool-use-config.json

json

{
  "hooks": {
    "postToolUse": {
      "script": "./.claude/hooks/file-size-warning-monitor.sh",
      "matchers": [
        "write",
        "edit"
      ]
    }
  }
}

post-tool-use-script.sh

bash

#!/usr/bin/env bash

# Read the tool input from stdin
INPUT=$(cat)
TOOL_NAME=$(echo "$INPUT" | jq -r '.tool_name')
FILE_PATH=$(echo "$INPUT" | jq -r '.tool_input.file_path // .tool_input.path // ""')

if [ -z "$FILE_PATH" ]; then
  exit 0
fi

# Check if file exists and is a regular file
if [ ! -f "$FILE_PATH" ]; then
  exit 0
fi

echo "📏 Checking file size for: $(basename "$FILE_PATH")" >&2

# Get file size in bytes (cross-platform)
get_file_size() {
  local file="$1"
  
  # Try different stat formats for cross-platform compatibility
  if stat -f%z "$file" 2>/dev/null; then
    # macOS/BSD
    return 0
  elif stat -c%s "$file" 2>/dev/null; then
    # Linux/GNU
    return 0
  elif [ -f "$file" ]; then
    # Fallback: use wc for text files (less accurate for binary)
    wc -c < "$file" 2>/dev/null || echo "0"
  else
    echo "0"
  fi
}

# Convert bytes to human-readable format
format_size() {
  local bytes="$1"
  
  if [ "$bytes" -lt 1024 ]; then
    echo "${bytes}B"
  elif [ "$bytes" -lt 1048576 ]; then
    echo "$((bytes / 1024))KB"
  elif [ "$bytes" -lt 1073741824 ]; then
    echo "$((bytes / 1048576))MB"
  else
    echo "$((bytes / 1073741824))GB"
  fi
}

# Get file extension
get_file_extension() {
  local file="$1"
  echo "${file##*.}" | tr '[:upper:]' '[:lower:]'
}

# Define file type categories and their thresholds
get_size_threshold() {
  local extension="$1"
  
  case "$extension" in
    # Source code files - should be relatively small
    js|jsx|ts|tsx|py|rb|go|rs|java|cpp|c|h|hpp|php|cs)
      echo "500000"  # 500KB
      ;;
    # Data/config files
    json|xml|yaml|yml|toml|ini|conf)
      echo "1048576"  # 1MB
      ;;
    # Documentation
    md|txt|rst|org)
      echo "1048576"  # 1MB
      ;;
    # Images
    jpg|jpeg|png|gif|bmp|webp|svg)
      echo "2097152"  # 2MB
      ;;
    # Videos
    mp4|avi|mov|wmv|flv|webm|mkv)
      echo "52428800"  # 50MB
      ;;
    # Audio
    mp3|wav|flac|aac|ogg)
      echo "10485760"  # 10MB
      ;;
    # Archives
    zip|tar|gz|bz2|xz|7z|rar)
      echo "20971520"  # 20MB
      ;;
    # Binary executables
    exe|bin|app|dmg|deb|rpm)
      echo "104857600"  # 100MB
      ;;
    # Default for unknown file types
    *)
      echo "5242880"  # 5MB
      ;;
  esac
}

# Get optimization suggestions for file type
get_optimization_suggestions() {
  local extension="$1"
  local size_mb="$2"
  
  case "$extension" in
    js|jsx|ts|tsx)
      echo "Consider code splitting, tree shaking, or minification"
      ;;
    json)
      echo "Consider JSON streaming, compression, or breaking into smaller files"
      ;;
    jpg|jpeg)
      echo "Consider JPEG optimization, WebP format, or progressive JPEG"
      ;;
    png)
      echo "Consider PNG optimization, WebP format, or SVG for simple graphics"
      ;;
    gif)
      echo "Consider converting to WebP or MP4 for better compression"
      ;;
    svg)
      echo "Consider SVG optimization tools to remove unnecessary elements"
      ;;
    mp4|mov)
      echo "Consider video compression, lower resolution, or streaming"
      ;;
    pdf)
      echo "Consider PDF compression or splitting into smaller documents"
      ;;
    zip|tar|gz)
      echo "Archive seems large - verify contents are necessary"
      ;;
    md|txt)
      echo "Consider breaking into smaller documents or using external storage"
      ;;
    *)
      echo "Consider file compression or alternative storage solutions"
      ;;
  esac
}

# Get file size
SIZE_BYTES=$(get_file_size "$FILE_PATH")
SIZE_HUMAN=$(format_size "$SIZE_BYTES")
SIZE_MB=$((SIZE_BYTES / 1048576))
SIZE_KB=$((SIZE_BYTES / 1024))

# Get file info
FILE_EXTENSION=$(get_file_extension "$FILE_PATH")
FILE_NAME=$(basename "$FILE_PATH")
THRESHOLD_BYTES=$(get_size_threshold "$FILE_EXTENSION")
THRESHOLD_HUMAN=$(format_size "$THRESHOLD_BYTES")

echo "📊 File: $FILE_NAME ($SIZE_HUMAN)" >&2

# Check if file exceeds threshold
if [ "$SIZE_BYTES" -gt "$THRESHOLD_BYTES" ]; then
  echo "⚠️ SIZE WARNING: File exceeds recommended threshold for .$FILE_EXTENSION files" >&2
  echo "   Current: $SIZE_HUMAN | Recommended: < $THRESHOLD_HUMAN" >&2
  
  # Provide optimization suggestions
  SUGGESTION=$(get_optimization_suggestions "$FILE_EXTENSION" "$SIZE_MB")
  echo "💡 Suggestion: $SUGGESTION" >&2
  
  # Specific warnings for very large files
  if [ "$SIZE_MB" -gt 50 ]; then
    echo "🚨 VERY LARGE FILE: This file may cause performance issues" >&2
    echo "   Consider using Git LFS for files over 50MB" >&2
  elif [ "$SIZE_MB" -gt 10 ]; then
    echo "⚠️ LARGE FILE: May impact repository performance" >&2
  fi
  
else
  echo "✅ File size within acceptable range ($THRESHOLD_HUMAN threshold)" >&2
fi

# Special checks for specific file types
case "$FILE_EXTENSION" in
  js|jsx|ts|tsx)
    if [ "$SIZE_KB" -gt 100 ]; then
      echo "📦 JavaScript bundle size check: Consider code splitting for better performance" >&2
    fi
    ;;
  json)
    if [ "$SIZE_KB" -gt 500 ]; then
      echo "📄 Large JSON detected: Consider pagination or streaming for API responses" >&2
    fi
    ;;
  jpg|jpeg|png|gif|webp)
    if [ "$SIZE_KB" -gt 500 ]; then
      echo "🖼️ Image optimization: Large images impact web performance" >&2
      if command -v identify &> /dev/null; then
        DIMENSIONS=$(identify -format '%wx%h' "$FILE_PATH" 2>/dev/null || echo "unknown")
        echo "   Dimensions: $DIMENSIONS" >&2
      fi
    fi
    ;;
  css|scss|sass)
    if [ "$SIZE_KB" -gt 200 ]; then
      echo "🎨 CSS size check: Consider removing unused styles or splitting stylesheets" >&2
    fi
    ;;
esac

# Check if file is in git repository
if command -v git &> /dev/null && git rev-parse --git-dir > /dev/null 2>&1; then
  # Check if file is tracked by git
  if git ls-files --error-unmatch "$FILE_PATH" &> /dev/null; then
    echo "🔄 Git repository impact:" >&2
    
    # Check if file has grown significantly
    if git log --oneline -n 1 -- "$FILE_PATH" &> /dev/null; then
      # File has history, check previous size
      PREV_SIZE=$(git show HEAD:"$FILE_PATH" 2>/dev/null | wc -c | xargs || echo "0")
      if [ "$PREV_SIZE" -gt 0 ]; then
        PREV_SIZE_HUMAN=$(format_size "$PREV_SIZE")
        SIZE_DIFF=$((SIZE_BYTES - PREV_SIZE))
        
        if [ "$SIZE_DIFF" -gt 0 ]; then
          DIFF_HUMAN=$(format_size "$SIZE_DIFF")
          PERCENT_INCREASE=$((SIZE_DIFF * 100 / PREV_SIZE))
          echo "   Size change: +$DIFF_HUMAN (+$PERCENT_INCREASE%) from previous version" >&2
          
          if [ "$PERCENT_INCREASE" -gt 100 ]; then
            echo "   📈 Significant size increase detected" >&2
          fi
        fi
      fi
    fi
    
    # Suggest Git LFS for large files
    if [ "$SIZE_MB" -gt 10 ]; then
      echo "   💡 Consider using Git LFS for this large file" >&2
      if [ -f ".gitattributes" ]; then
        if ! grep -q "*.$FILE_EXTENSION.*lfs" ".gitattributes" 2>/dev/null; then
          echo "   Add to .gitattributes: *.$FILE_EXTENSION filter=lfs diff=lfs merge=lfs -text" >&2
        fi
      else
        echo "   Create .gitattributes with: *.$FILE_EXTENSION filter=lfs diff=lfs merge=lfs -text" >&2
      fi
    fi
  fi
fi

# Overall performance impact assessment
echo "" >&2
echo "📋 Performance Impact Assessment:" >&2

if [ "$SIZE_MB" -gt 50 ]; then
  echo "  🔴 High Impact: File may cause significant performance issues" >&2
elif [ "$SIZE_MB" -gt 10 ]; then
  echo "  🟡 Medium Impact: File may cause minor performance issues" >&2
elif [ "$SIZE_KB" -gt 500 ]; then
  echo "  🟢 Low Impact: File size is acceptable but monitor growth" >&2
else
  echo "  ✅ Minimal Impact: File size is optimal" >&2
fi

echo "" >&2
echo "💡 File Size Best Practices:" >&2
echo "   • Keep source code files under 500KB" >&2
echo "   • Optimize images before committing" >&2
echo "   • Use Git LFS for files over 10MB" >&2
echo "   • Consider file compression for large data files" >&2

exit 0

File Size Warning Monitor - Hook - Claude Pro Directory

Claude Code Setup

Configuration Paths

Requirements

Reviews (0)

Category

Source

Accessibility Checker

API Endpoint Documentation Generator

Auto Code Formatter Hook