setting-up-just

name	setting-up-just
version	0.1.0
description	Set up a repo-local just task runner with a root Justfile, optional .just/ helper scripts, and curated help, build, fmt, lint, test, and ci recipes. Use when a repo needs just, a Justfile, .just helpers, or when the user mentions task automation, "just build", "just lint", "just fmt", or dropping in a just system.

Setting Up Just

Use this skill when a repository needs a consistent just command surface. Prefer the atm-core pattern: keep the root Justfile readable and move non-trivial orchestration into .just/*.py helpers.

Within this package, the helpers are intentionally generic. Repo-specific commands, aliases, and discovery knobs belong in .just/config.toml.

Scope

Use this skill for:

• adding a new root Justfile
• introducing a .just/ helper directory
• standardizing help, build, fmt, lint, test, and ci recipes
• replacing ad hoc shell snippets with small Python helpers when recipes get noisy

Do not use this skill for:

• one-off shell aliases
• large build-system migrations that should stay in an existing framework
• repos that already have a strong task-runner standard the user wants preserved

Step 1 — Verify just And python3

Before editing files:

1. Verify just >= 1.0 is installed:
   • command -v just || which just
   • just --version
2. Verify python3 >= 3.11 is available:
   • command -v python3 || command -v python
   • python3 -c "import sys; print(sys.version)" || python -c "import sys; print(sys.version)"
3. If either command is missing from PATH, probe common install locations before assuming the tool is absent:
   • for candidate in "$HOME/.cargo/bin/just" "/opt/homebrew/bin/just" "$HOME/.local/bin/just"; do [ -x "$candidate" ] && "$candidate" --version; done
   • for candidate in "/opt/homebrew/bin/python3" "$HOME/.local/bin/python3"; do [ -x "$candidate" ] && "$candidate" -c "import sys; print(sys.version)"; done
4. Enforce the version floor before continuing:
   • stop if just --version reports lower than 1.0
   • stop if the resolved Python interpreter reports lower than 3.11
5. If dependency discovery or version checks fail, read references/installation-and-troubleshooting.md and do not continue until the tool is both discoverable and new enough.
6. Inspect the repo for existing task surfaces such as Makefile, package.json, pyproject.toml, Cargo.toml, scripts/, or CI workflows.
7. If a Justfile already exists, merge carefully instead of replacing it.

Template Selection

Read references/template-catalog.md and choose the closest profile:

• minimal for a generic starter with placeholder command lists
• python for Python repos that can use ruff + pytest
• go for Go repos where go build ./... and go test ./... from repo root are the correct default
• dotnet for .NET repos where root-level dotnet build and dotnet test are the correct default
• rust for Cargo workspaces that want the atm-core shape

Then read references/adoption-workflow.md and adapt the copied files to the repo's real toolchain. If dependency setup is failing, also read references/installation-and-troubleshooting.md.

Workflow

When applying this skill:

1. Detect the repo shape and choose the closest template profile.
2. Copy the selected template files into the repo root.
3. Update .just/config.toml so all repo-specific commands and aliases match the target repo.
4. Keep the top-level Justfile concise; prefer delegating branching logic to .just/*.py.
5. If the repo already has scripts or package-manager entry points, call those from just instead of re-implementing their behavior.
6. Verify the final surface with non-destructive checks first:
   • just help
   • just build when the template exposes it
   • just fmt check or the repo-safe equivalent
   • just lint
   • just test
7. If a verification command fails, do not leave the template in a knowingly broken state:
   • change .just/config.toml first when the repo uses different commands
   • only add or change helper scripts when direct config updates are no longer adequate
   • if the repo surface is still unresolved, report the failure clearly and stop instead of claiming the setup is complete

Output Expectations

When using this skill, report:

• which template profile you selected and why
• what commands were wired into fmt, lint, test, and ci
• any repo-specific deviations from the starter template
• whether .just/config.toml stayed sufficient or whether helper code had to change
• which verification commands passed and which were not run

References

• references/template-catalog.md
• references/adoption-workflow.md
• references/installation-and-troubleshooting.md

Agent Delegation

This skill operates directly in the main session. It does not require background agents or Task-tool delegation.