Install Rigor — instructions for an AI agent

These instructions are written for an AI coding agent. Follow each step in order. Run the shell commands exactly as shown. If a step fails, stop and report the error before continuing.

The goal is to install Rigor and hand off to the project-init skill. Do not add Rigor to the project’s Gemfile — Rigor is a standalone tool, not a library.

Step 1 — Detect the environment

Run these four checks and note which tools are available:

which mise    # preferred — see Step 2A
which asdf    # fallback — see Step 2B
ruby --version 2>/dev/null | head -1   # is Ruby 4.0 already on PATH?
which docker  # last resort — see Step 2D

Then proceed to the first matching case below.

Step 2 — Install Ruby 4.0 and Rigor

Case A — mise is available (recommended)

What is mise? mise is a runtime and tool version manager — think rbenv + nvm combined, plus a task runner. It installs and pins language runtimes (Ruby, Node, Python, …) and tool gems (like rigortype) per project, recording versions in a mise.toml that can be committed alongside the code. Other contributors — and CI — run mise install to restore the exact same versions with no Gemfile involvement.

Run in the project root:

mise use ruby@4.0
mise use gem:rigortype

mise use installs the tools and writes their versions to mise.toml in one step. Commit mise.toml so the version is shared.

Then verify:

rigor --version

If rigor is not found, mise may not be wired into your shell yet. Run one of:

# Interactive shells (add to ~/.zshrc / ~/.bashrc permanently):
eval "$(mise activate zsh)"   # or bash / fish

# Or use the shims directory directly:
export PATH="$HOME/.local/share/mise/shims:$PATH"

Then re-run rigor --version. If it still fails, run mise exec gem:rigortype -- rigor --version as a one-off check.

Case B — asdf is available

asdf follows the same model as mise but has no gem backend, so the gem is installed with gem install after setting the Ruby version.

asdf install ruby latest:4.0
asdf local ruby latest:4.0
gem install rigortype

Verify:

rigor --version

Note: unlike mise, gem install here does not pin the version in a project config file. Consider switching to mise for per-project pinning; see https://mise.jdx.dev/getting-started.html.

Case C — Ruby 4.0 is already on PATH

If ruby --version reports ruby 4.0.*, install the gem directly:

gem install rigortype

Verify:

rigor --version

No version is pinned per project with this approach; a version manager (Case A or B) is better for shared codebases.

Case D — mise is not installed yet (no ruby, no asdf)

Install mise first by following the official getting-started guide: https://mise.jdx.dev/getting-started.html

The one-line script from that page is:

curl https://mise.run | sh

After mise is installed and activated in your shell, come back and follow Case A.

Last resort — Docker

If none of the above is workable in your environment, you can run Rigor inside a Docker container:

docker run --rm -v "$(pwd):/app" -w /app ghcr.io/rigortype/rigor:latest rigor check

This approach adds overhead from the container filesystem boundary and does not integrate well with editor LSP. Use it only when a host-side Ruby 4.0 is genuinely unavailable (for example, Windows without WSL). For all other environments, prefer Case A–D above.

Step 3 — Verify the installation

rigor --version

A version string like rigor 0.1.x confirms a successful install. If the command is not found, revisit Step 2 for your case.

Step 4 — Set up Rigor in this project

Now that rigor is on your PATH, run the project-init skill:

rigor skill print rigor-project-init

This prints the SKILL definition — a header with file paths followed by the skill body. Follow the printed instructions from top to bottom. The skill detects your project’s stack, proposes plugins, writes .rigor.dist.yml, and snapshots a baseline if needed.

If the skill command is not recognised, your Rigor version may be older than 0.1.9. Run rigor --version and upgrade with mise use gem:rigortype (or gem update rigortype for Case C/B).