ruby_expert

ruby_expert is a skill for Claude Code, Codex from ApexIQ/skillsmith. It costs 23 tokens per session (279 once invoked), scanned A, original, MIT.

A set of guidelines for Ruby and Ruby on Rails development, including common Rails structure, database-query patterns, dependency management, security, and automated testing.

In plain words
What is it for?
Use it to build or review Ruby and Rails applications, organize business logic, manage gems, improve ActiveRecord queries, and write RSpec tests.
Why use it?
It reduces repeated design choices and helps prevent issues such as inefficient database queries, SQL injection, cross-site scripting, and overly complex code.

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/apexiq/skillsmith/ruby_expert
Any agent
npx skills add ApexIQ/skillsmith --skill ruby_expert
Clone the repo
git clone --depth 1 https://github.com/ApexIQ/skillsmith

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_expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/apexiq/skillsmith/ruby_expert.svg)](https://agentmods.dev/skills/apexiq/skillsmith/ruby_expert)
Your own site
<a href="https://agentmods.dev/skills/apexiq/skillsmith/ruby_expert"><img src="https://agentmods.dev/badge/skills/apexiq/skillsmith/ruby_expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 279 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 $0.00023 $0.00279
Opus 5 $0.00012 $0.00139
Sonnet 5 $0.00005 $0.00056
Haiku 4.5 $0.00002 $0.00028

Measured today against content hash afd5f017e49e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ruby_expert 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 today.

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.

src/skillsmith/templates/.agent/skills/ruby_expert/SKILL.md · 36 lines

What it actually says

Ruby Expert

Professional guidelines for Ruby and Ruby on Rails development.

Philosophy

  • Developer Happiness: Write code that is beautiful, readable, and fun to work with.
  • Convention over Configuration: Follow established patterns to reduce decision fatigue.
  • DRY (Don't Repeat Yourself): Eliminate redundancy through modularity and metaprogramming.

Patterns

  • ActiveRecord: Use the ORM effectively, avoiding N+1 queries with includes.
  • Service Objects: Move complex business logic out of models and controllers.
  • Concerns: Extract shared logic into reusable modules.
  • TDD/BDD: Use RSpec for descriptive, behavior-driven testing.

Best Practices

  • Style Guide: Follow the community Ruby Style Guide (RuboCop).
  • Gem Management: Use Bundler for dependency management.
  • Security: Be vigilant about SQL injection, XSS, and mass assignment in Rails.
  • Metaprogramming: Use sparingly; prioritize clarity over "clever" code.
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. today First seen · 36 lines · 23 tokens per session scan A afd5f017e49e

Subscribe to this mod's changes

ruby_expert is a skill published in the GitHub repository ApexIQ/skillsmith (5 stars, last pushed 5mo ago), licensed MIT. It adds 23 tokens to every session and 279 once invoked, about $0.0001 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 2026-09-03.

Related

Other skills, from other repositories

Ruby Patterns

Use this skill when working in Ruby projects (Rails or otherwise) and you want clean object boundaries, predictable dependency management, and maintainable code organization.

AmariahAK/atlarix-skills · 2 tokens

ruby-gc

Audit asdf-installed Ruby versions against project pins and remove unreferenced ones. Dry-run by default.

joshukraine/dotfiles · 25 tokens

ruby-rails

Use this skill when building Ruby on Rails applications — MVC, ActiveRecord, service objects, API mode, background jobs, and testing. This skill enforces: thin controllers, service objects for business logic, ActiveRecord query best practices, Rails API mode conventions, and RSpec testing patterns. Requires Rails 7+…

j4flmao/agent-skills · 94 tokens

rails-audit-thoughtbot

Perform comprehensive code audits of Ruby on Rails applications based on thoughtbot best practices. Use this skill when the user requests a code audit, code review, quality assessment, or analysis of a Rails application. The skill analyzes the entire codebase focusing on testing practices (RSpec), security…

thoughtbot/rails-audit-thoughtbot · 130 tokens

monitor-test-run

Watch a running Kobiton test run and narrate it to the user: read the org's live-remediation flag up front, poll the run until every execution is terminal, surface the live-remediation URL the moment an execution is blocked, and give a correct post-mortem so a COMPLETED-with-BLOCKERENCOUNTERED execution is never…

kobiton/automate · 215 tokens

run-automation-suite

Run local Appium test scripts against Kobiton devices. Guides through app upload, device selection, capability parsing, and local execution. Use when the user asks to run mobile tests, validate an APK or IPA on Kobiton devices, or kick off an Appium suite from a local script directory. Trigger with "run kobiton tests"…

kobiton/automate · 81 tokens