hook pre-command

Execute pre-command validations and safety checks before running shell commands.

Usage

npx claude-flow hook pre-command [options]

Options

• --command, -c <cmd> - Command to be executed
• --validate-safety - Check command safety (default: true)
• --check-permissions - Verify execution permissions
• --estimate-duration - Estimate command runtime
• --dry-run - Preview without executing

Examples

Basic pre-command hook

npx claude-flow hook pre-command --command "npm install express"

Safety validation

npx claude-flow hook pre-command -c "rm -rf node_modules" --validate-safety

Permission check

npx claude-flow hook pre-command -c "sudo apt update" --check-permissions

Dry run preview

npx claude-flow hook pre-command -c "git push origin main" --dry-run

Features

Safety Validation

• Detects dangerous commands
• Warns about destructive operations
• Checks for sudo/admin usage
• Validates command syntax

Permission Checking

• Verifies execution rights
• Checks directory access
• Validates file permissions
• Ensures proper context

Duration Estimation

• Predicts execution time
• Warns about long operations
• Suggests timeouts
• Tracks historical data

Dry Run Mode

• Shows command effects
• Lists files affected
• Previews changes
• No actual execution

Integration

This hook is automatically called by Claude Code when:

• Using Bash tool
• Running shell commands
• Executing npm/pip/cargo commands
• System operations

Manual usage in agents:

# Before running commands
npx claude-flow hook pre-command --command "your command here" --validate-safety

Output

Returns JSON with:

{
  "continue": true,
  "command": "npm install express",
  "safe": true,
  "estimatedDuration": 15000,
  "warnings": [],
  "permissions": "user",
  "affectedFiles": ["package.json", "package-lock.json"],
  "dryRunOutput": "Would install 50 packages"
}

See Also

• hook post-command - Post-command processing
• Bash - Command execution tool
• terminal execute - Terminal operations
• security scan - Security validation