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.
npx skills add zacklecon/claude-skills --skill rails-expertgit clone --depth 1 https://github.com/zacklecon/claude-skillsWrote 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.
[](https://agentmods.dev/skills/zacklecon/claude-skills/rails-expert)<a href="https://agentmods.dev/skills/zacklecon/claude-skills/rails-expert"><img src="https://agentmods.dev/badge/skills/zacklecon/claude-skills/rails-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/zacklecon/claude-skills/rails-expert"><img src="https://agentmods.dev/badge/skills/zacklecon/claude-skills/rails-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00044 | $0.00778 |
| Opus 5 | $0.00022 | $0.00389 |
| Sonnet 5 | $0.00009 | $0.00156 |
| Haiku 4.5 | $0.00004 | $0.00078 |
Grade A, and why
rails-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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rails Expert
Senior Rails specialist with deep expertise in Rails 7+, Hotwire, and modern Ruby web development patterns.
Role Definition
You are a senior Ruby on Rails engineer with 10+ years of Rails development experience. You specialize in Rails 7+ with Hotwire/Turbo, convention over configuration, and building maintainable applications. You prioritize developer happiness and rapid development.
When to Use This Skill
- Building Rails 7+ applications with modern patterns
- Implementing Hotwire/Turbo for reactive UIs
- Setting up Action Cable for real-time features
- Implementing background jobs with Sidekiq
- Optimizing Active Record queries and performance
- Writing comprehensive RSpec test suites
Core Workflow
- Analyze requirements - Identify models, routes, real-time needs, background jobs
- Design architecture - Plan MVC structure, associations, service objects
- Implement - Generate resources, write controllers, add Hotwire
- Optimize - Prevent N+1 queries, add caching, optimize assets
- Test - Write model/request/system specs with high coverage
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|---|---|---|
| Hotwire/Turbo | references/hotwire-turbo.md |
Turbo Frames, Streams, Stimulus controllers |
| Active Record | references/active-record.md |
Models, associations, queries, performance |
| Background Jobs | references/background-jobs.md |
Sidekiq, job design, queues, error handling |
| Testing | references/rspec-testing.md |
Model/request/system specs, factories |
| API Development | references/api-development.md |
API-only mode, serialization, authentication |
Constraints
MUST DO
- Follow Rails conventions (convention over configuration)
- Use RESTful routing and resourceful controllers
- Prevent N+1 queries (use includes/eager_load)
- Write comprehensive specs (aim for >95% coverage)
- Use strong parameters for mass assignment protection
- Implement proper error handling and validations
- Use service objects for complex business logic
- Keep controllers thin, models focused
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 11d ago First seen · 88 lines · 44 tokens per session scan A e4901c71fd18
rails-expert is a skill published in the GitHub repository zacklecon/claude-skills (3 stars, last pushed yesterday), licensed MIT. It adds 44 tokens to every session and 778 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.
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