Overview

Just is a modern command runner that provides a much-needed upgrade to traditional makefiles. It offers a cleaner syntax, better error handling, and powerful features like command inheritance and parameter passing that make it ideal for development workflows.

Key Features

• Clean Syntax: Simple, readable command definitions without make’s complex syntax
• Command Inheritance: Commands can inherit and extend other commands
• Parameter Passing: Pass parameters between commands for flexible workflows
• Cross-Platform: Works consistently across different operating systems
• Shell Integration: Integrates seamlessly with existing shell environments

Common Use Cases

Global Task Runner

Create a global ~/.justfile for general-purpose tasks:

# Common development tasks
dev:
    bun run dev

build:
    npm run build

# Generic AI agent integration (replace 'ai-agent' with your specific agent command)
ask question:
    ai-agent "{{question}}"

clean:
    rm -rf node_modules dist

Project-Specific Commands

Include project-specific justfiles alongside global ones:

# Project-specific build commands
test:
    bun run test

deploy env="production":
    bun run build
    npm run deploy:{{env}}

Why Developers Choose Just

• Faster than make: No parsing overhead, executes commands directly
• Better error messages: Clear, helpful error reporting
• No tabs required: Unlike make, just uses standard spacing
• IDE friendly: Works well with modern development tools
• AI agent compatible: Perfect for Claude and other CLI agents

Integration with AI Agents

Just works particularly well with AI coding agents like OpenCode:

# Quick AI assistance
fix file:
    opencode "Fix the issues in {{file}}"

review:
    opencode "Review the current codebase and suggest improvements"

optimize:
    opencode "Optimize the performance of this application"

Resources

• Official Documentation
• Installation Guide
• Examples Repository

Just provides the power of make with modern developer experience, making it an essential tool for terminal-based development workflows.