Use for just/justfile task automation: create justfiles, write recipes, configure settings, add modules/attributes, or set up command-runner workflows.

Just Command Runner Create readable task automation that matches the repository's installed Just version and existing justfile conventions. Defaults Inspect just version , the existing justfile/module tree, and just list before editing. Installed capabilities and existing syntax are authoritative over this skill's examples. Preserve bespoke formatting. Do not rewrite a justfile with just fmt ; use just fmt check only when the repository explicitly treats the built in formatter as authoritative. just dump is inspection output, not a formatting source. Define multi item string sequences one item per line with a parenthesized concatenation. Keep a trailing separator in every non final item; do not collapse them into one long string. Triple quoted strings are for values whose newlines are semantic, not visual wrapping. For example: Prefer explicit, small recipes; Just native executable checks; private helpers; check/write recipe pairs; and aliases after their target recipes. Prefer which() plus assert() with actionable install guidance over shell command v or backtick which checks when the justfile already enables set unstable and set lists . Otherwise, use require() when its generic missing executable error is sufficient. Put an assertion at top level only when every recipe needs that tool; otherwise make it a private prerequisite of the affected recipes. Make recipes quiet by default: prefix the recipe name with @ unless echoing commands has clear value. Recipe level @ inverts per line @ , so never also prefix lines inside a @recipe . Never add @ to a [script] recipe: scripts are already quiet, and @ un mutes them. See "Quiet Recipes and Command Prefixes" in references/recipes.md . On stock macOS, assume /bin/bash 3.2 unless the recipe explicitly selects a newer shell. Use the user's section banner style when creating a new standalone justfile; existing repository organization overrides it. Workflow 1. Determine the requested recipe behavior, inputs, outputs, cwd, shell, environment, dependencies, and success condition. 2. Use the installed manual ( just help , just man , or <https://just.systems/man/en/ ) for version sensitive syntax. Read only the task specific reference: Task Reference Recipes, parameters, dependencies, cache references/recipes.md Settings, dotenv, lists, modules references/settings.md Expressions, functions, constants references/syntax.md Shell or script recipes references/inline scripts.md Check/write, status, aliases, organization references/patterns.md 3. Make the smallest recipe or setting change. Do not enable unstable features unless the requested design needs them and the installed version supports them. 4. Validate parsing with just list or just summary , then execute the narrowest safe recipe path. For state changing recipes, use an existing dry run/check mode or inspect the expanded command first. Opinionated Organization For a new standalone file, prefer dependency declarations, constants, public recipes, checks, then private helpers. Use set default list := true when no single default action makes sense and the installed version supports it. Example starting points live in examples/standalone.just and examples/devkit.just ; load one only when creating that shape. Completion requires a parsable justfile, the requested recipe behavior, and execution or dry run evidence appropriate to its side effects. Finish with ✅ Just workflow ready , a compact recipe/alias/purpose table when several entries changed, and 🧪 Verification with exact commands and outcomes. Keep confirmation prompts, recipe data output, compiler output, and just list output undecorated; preserve the repository's own banner vocabulary.

cli-just