Julia Comonicon

Julia Comonicon

Use Comonicon to turn Julia functions/modules into CLI commands.

Quick Start: Single Command Script

Use @main on a function for one-command CLIs:

using Comonicon

"""
Example CLI.

# Arguments
- `input`: input value.

# Options
- `-o, --output `: output path.

# Flags
- `-f, --force`: overwrite existing files.
"""
@main function mycmd(input; output="out.txt", force::Bool=false)
    println("input=", input, " output=", output, " force=", force)
end

Run with:

julia myscript.jl -h

If creating an executable script, add a Julia shebang and chmod +x.

Build a Multi-Command CLI Package

Use @cast to register leaf commands and modules, then @main for the entry:

module Demo
using Comonicon

@cast greet(name; loud::Bool=false) = loud ? println(uppercase(name)) : println(name)
@cast version() = println("Demo CLI")

module Admin
using Comonicon
@cast prune(days::Int=30) = println("pruning older than ", days, " days")
end

@cast Admin
@main

end # module

Prefer package-style CLIs for serious use. This gives install/build workflows and better startup optimization options.

Use the Built-In Entry/Install Functions

After @main, Comonicon generates module helpers, including:

• command_main for CLI entry.
• comonicon_install and comonicon_install_path for install flows.
• julia_main for standalone application builds.
• CASTED_COMMANDS registry for generated command AST/metadata.

Use a deps/build.jl install entry like:

using Demo
Demo.comonicon_install()

Follow Comonicon Naming and Help Conventions

• Map positional arguments to CLI arguments.
• Map keyword arguments to options/flags.
• Use Bool=false kwargs for flags.
• Expect _ in kwarg names to become - in CLI long options.
• Use docstring sections # Arguments, # Options, and # Flags for rich help.
• Remember -h/--help and --version are always generated.

For exact syntax patterns, open references/conventions.md.

Configure Build and Advanced Behavior

Use Comonicon.toml (or JuliaComonicon.toml) in project root for behavior like plugin enablement and system-image/application builds.

For concrete templates and installation/build flow, open references/project-workflow.md.

Related Skills

• julia-package-dev - creating Julia packages and managing package or Pkg-app workflows
• julia-tests - running package tests while developing CLI code

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Krastanov
• Source: Krastanov/JuliaLLMAgentSkills
• License: Unlicense

Install and usage instructions live in the source repository linked above.