How do I install the Ruby Version skill?

Run npx skillmds@latest add rolemodel/ruby-version in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Ruby Version safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Ruby Version?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Ruby Version free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Ruby Version?

rolemodel (@rolemodel) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Ruby Version by rolemodel — Agent Skill

Name: Ruby Version
Author: rolemodel

Ruby Version

Verify what Ruby versions actually exist and install a specific Ruby via rbenv. Use BEFORE asserting that any Ruby version does or doesn't exist (e.g., "Ruby 4.0 isn't out yet", "the latest Ruby is 3.x", "Ruby X.Y.Z doesn't exist"). Also use when the user asks "what's the latest Ruby", "is Ruby X out", "does Ruby X.Y exist", "install Ruby", "switch to Ruby X", "what Ruby is installed", or mentions a specific Ruby version you're unsure about. Claude's training data may be out of date — run `check.sh` first.

rolemodel b2672e2 3 files · 5.8 KB Updated Sep 17, 2026

File contents

ruby-version

Two-script skill that prevents the agent from hallucinating Ruby release information and provides a one-liner Ruby install.

When to invoke this skill

Mandatory: run check.sh before making any claim about whether a specific Ruby version exists, has been released, or is the latest. Claude's training cutoff lags real Ruby releases — guessing is the failure mode this skill exists to prevent.

Also invoke when the user:

Asks what Ruby versions are installed.
Asks for the latest stable Ruby.
Wants to install a specific Ruby (install.sh).

Scripts

`scripts/check.sh`

Prints:

The latest stable MRI Ruby known to local ruby-build.
All Ruby versions currently installed via rbenv.
The ruby-build version (so staleness is visible — if it's months old, "latest" may lag reality).

bash skills/ruby-version/scripts/check.sh

No arguments. Exits non-zero with a remediation hint if rbenv or ruby-build is missing.

How to read the output: The line beginning latest-stable: is the highest stable MRI release ruby-build knows about. Treat that as ground truth over any version number you recall from training data. The installed: block is what the user has on this machine; an empty list means none installed via rbenv.

`scripts/install.sh <version>`

Installs a specific Ruby via rbenv + ruby-build. Validates the version exists in ruby-build's known list first.

bash skills/ruby-version/scripts/install.sh 3.4.2

Does not set the version as global or local. After install, suggest the user run rbenv global <version> or cd <project> && rbenv local <version> based on their intent.

If the requested version isn't in rbenv install -l, the script prints a hint to upgrade ruby-build (brew upgrade ruby-build) rather than failing silently.

Assumptions

macOS with Homebrew, rbenv, and ruby-build installed.
Scripts are bash (not Ruby) so they work even when Ruby is missing or broken.

Anti-patterns

Do not assert "Ruby X doesn't exist yet" from memory. Run check.sh.
Do not have install.sh auto-set global or local Ruby — that's a user decision.
Do not extend this skill into gemset/bundler management. It is a verification + install helper, nothing more.

---name: ruby-versiondescription: Verify what Ruby versions actually exist and install a specific Ruby via rbenv. Use BEFORE asserting that any Ruby version does or doesn't exist (e.g., "Ruby 4.0 isn't out yet", "the latest Ruby is 3.x", "Ruby X.Y.Z doesn't exist"). Also use when the user asks "what's the latest Ruby", "is Ruby X out", "does Ruby X.Y exist", "install Ruby", "switch to Ruby X", "what Ruby is installed", or mentions a specific Ruby version you're unsure about. Claude's training data may be out of date — run `check.sh` first.license: MIT---# ruby-versionTwo-script skill that prevents the agent from hallucinating Ruby release information and provides a one-liner Ruby install.## When to invoke this skill**Mandatory: run `check.sh` before making any claim about whether a specific Ruby version exists, has been released, or is the latest.** Claude's training cutoff lags real Ruby releases — guessing is the failure mode this skill exists to prevent.Also invoke when the user:- Asks what Ruby versions are installed.- Asks for the latest stable Ruby.- Wants to install a specific Ruby (`install.sh`).## Scripts### `scripts/check.sh`Prints:- The latest stable MRI Ruby known to local ruby-build.- All Ruby versions currently installed via rbenv.- The ruby-build version (so staleness is visible — if it's months old, "latest" may lag reality).```bashbash skills/ruby-version/scripts/check.sh```No arguments. Exits non-zero with a remediation hint if `rbenv` or `ruby-build` is missing.**How to read the output:** The line beginning `latest-stable:` is the highest stable MRI release ruby-build knows about. Treat that as ground truth over any version number you recall from training data. The `installed:` block is what the user has on this machine; an empty list means none installed via rbenv.### `scripts/install.sh <version>`Installs a specific Ruby via rbenv + ruby-build. Validates the version exists in ruby-build's known list first.```bashbash skills/ruby-version/scripts/install.sh 3.4.2```Does **not** set the version as global or local. After install, suggest the user run `rbenv global <version>` or `cd <project> && rbenv local <version>` based on their intent.If the requested version isn't in `rbenv install -l`, the script prints a hint to upgrade ruby-build (`brew upgrade ruby-build`) rather than failing silently.## Assumptions- macOS with Homebrew, rbenv, and ruby-build installed.- Scripts are bash (not Ruby) so they work even when Ruby is missing or broken.## Anti-patterns- Do not assert "Ruby X doesn't exist yet" from memory. Run `check.sh`.- Do not have `install.sh` auto-set global or local Ruby — that's a user decision.- Do not extend this skill into gemset/bundler management. It is a verification + install helper, nothing more.

Frequently asked questions