ruby

ruby is a skill for Claude Code, Codex from pledgeandgrow/pledge-skills. It costs 45 tokens per session (923 once invoked), scanned A, original, MIT.

A reference for Ruby, a programming language designed for readable, object-oriented code. It covers the language, its standard tools, libraries called gems, and testing.

In plain words
What is it for?
Use it when writing Ruby programs, working with classes, files, errors, concurrent code, metaprogramming, gems, tests, or native extensions.
Why use it?
It gives developers one place to look up Ruby syntax and behavior instead of piecing together information about language features and tools.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/pledgeandgrow/pledge-skills/ruby
Any agent
npx skills add pledgeandgrow/pledge-skills --skill ruby
Clone the repo
git clone --depth 1 https://github.com/pledgeandgrow/pledge-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ruby

README.md
[![agentmods](https://agentmods.dev/badge/skills/pledgeandgrow/pledge-skills/ruby.svg)](https://agentmods.dev/skills/pledgeandgrow/pledge-skills/ruby)
Your own site
<a href="https://agentmods.dev/skills/pledgeandgrow/pledge-skills/ruby"><img src="https://agentmods.dev/badge/skills/pledgeandgrow/pledge-skills/ruby.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 923 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00045 $0.00923
Opus 5 $0.00023 $0.00462
Sonnet 5 $0.00009 $0.00185
Haiku 4.5 $0.00005 $0.00092

Measured 4d ago against content hash b829abf5993d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ruby scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/ruby/SKILL.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ruby

A dynamic, open-source programming language focused on simplicity and productivity. Pure object-oriented, with elegant syntax, powerful metaprogramming, and a rich ecosystem.

Quick Reference

Topic File
Introduction (what is Ruby, installation, quickstart, IRB) introduction.md
Syntax (literals, assignment, control flow, pattern matching, operators, comments) syntax.md
Methods (definitions, arguments, keyword args, blocks, visibility, operator methods) methods.md
Classes and Modules (inheritance, mixins, Struct, Data, access modifiers, refinements) classes-and-modules.md
Core Types (String, Integer, Float, Array, Hash, Symbol, Range, Regexp, Nil) core-types.md
Blocks, Procs, and Lambdas (closures, currying, yield, method objects) blocks-procs-lambdas.md
Exceptions (raise, rescue, retry, custom exceptions, hierarchy) exceptions.md
I/O and Files (File, FileUtils, Dir, Pathname, IO, networking) io-and-files.md
Concurrency (Threads, Mutex, Fibers, Ractors, Queue, Async) concurrency.md
Metaprogramming (reflection, define_method, method_missing, eval, refinements) metaprogramming.md
Gems and Bundler (RubyGems, Gemfile, gemspec, publishing, versioning) gems-and-bundler.md
Testing (Minitest, RSpec, matchers, mocks, shared examples) testing.md
Standard Library (Enumerable, Comparable, JSON, YAML, CSV, Set, Time, Logger) standard-library.md
Style Guide (layout, naming, flow control, collections, comments, RuboCop) style-guide.md
C Extensions (C API, extconf.rb, TypedData, GC, FFI alternative) c-extensions.md
Tools and Ecosystem (Rake, RuboCop, YARD, debug, Pry, benchmarking, editors) tools.md

Core Concepts

  • Pure Object-Oriented: Everything is an object — numbers, strings, classes, modules, even nil.
  • Dynamic Typing: Types determined at runtime. Duck typing: focus on what an object can do, not what it is.
  • Blocks & Closures: First-class support for blocks, Procs, and lambdas — Ruby's way of passing code around.
  • Metaprogramming: Powerful reflection and dynamic code generation. Open classes, method_missing, define_method, refinements.
  • Expressive Syntax: Designed for developer happiness. Natural language-like constructs, optional parentheses, implicit returns.
  • Rich Standard Library: Enumerable, Comparable, JSON, YAML, CSV, Set, Logger, and more built-in.
  • Gem Ecosystem: RubyGems + Bundler for dependency management. Thousands of gems on rubygems.org.
  • Testing Culture: Built-in Minitest, popular RSpec, strong TDD/BDD traditions.

Read the full file on GitHub · 54 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 54 lines · 45 tokens per session scan A b829abf5993d

Subscribe to this mod's changes

ruby is a skill published in the GitHub repository pledgeandgrow/pledge-skills (10 stars, last pushed 1mo ago), licensed MIT. It adds 45 tokens to every session and 923 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.