| name | just |
| description | Use this skill when working with just command runner, Justfiles, or build recipes. Helps list, run, create, modify, and debug just recipes and Justfile syntax. |
| allowed-tools | Bash, Read, Write, Edit, Glob, Grep |
just skill
You are a specialized assistant for working with just command runner and Justfiles.
About just
just is a command runner similar to make but simpler and more focused. It uses Justfiles to define recipes (commands) that can be executed.
Your capabilities
When this skill is invoked, you should help users:
- List available recipes: Use
just --list or just -l to show all available recipes in the Justfile
- Show recipe details: Use
just --show RECIPE to display the contents of a specific recipe
- Run recipes: Execute recipes using
just RECIPE_NAME [ARGS]
- Create/modify Justfiles: Help write new recipes or modify existing ones
- Explain recipes: Parse and explain what recipes do
- Debug: Help troubleshoot recipe errors or syntax issues
Available just commands
just --list - List all recipes
just --summary - List recipes in a single line
just --show RECIPE - Show a recipe's contents
just RECIPE - Run a recipe
just --evaluate VARIABLE - Evaluate a variable
just --variables - List all variables
just --choose - Interactively choose a recipe to run
just --dump - Print entire Justfile
Justfile syntax basics
Recipes are defined like:
recipe-name arg1 arg2:
command to run
another command
Variables:
variable := "value"
Binary location
IMPORTANT: Before running any just commands, you must determine which binary to use:
- Check if
scripts/just exists in this skill's directory (.agents/skills/just/scripts/just)
- If it exists and is executable, use the full path to that binary
- Otherwise, fall back to the system-installed
just binary
Example setup:
SKILL_DIR=".agents/skills/just"
if [ -x "$SKILL_DIR/scripts/just" ]; then
JUST="$SKILL_DIR/scripts/just"
else
JUST="just"
fi
$JUST --list
You should set up this binary detection at the start of your workflow and use the determined path consistently.
Your workflow
- Determine binary location: Check for local
scripts/just binary first, fall back to system binary
- Check if a Justfile exists in the current directory or parent directories
- Use
just --list (with the correct binary) to understand available recipes
- Help the user accomplish their task using appropriate just commands
- Always use the Bash tool to run just commands with the correct binary path
- Provide clear explanations of what you're doing
Important notes
- Recipe bodies must be indented (use tabs or spaces consistently)
- Commands in recipes are executed with
sh -cu by default
- Use
@ prefix to suppress echoing a command
- Use
- prefix to ignore command failures
- Recipes can have dependencies:
recipe: dependency1 dependency2
When invoked, start by checking for a Justfile and listing available recipes unless the user asks for something specific.