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 eric861129/SKILLS_All-in-one --skill rails-expertgit clone --depth 1 https://github.com/eric861129/SKILLS_All-in-oneWrote 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/eric861129/skills_all-in-one/rails-expert)<a href="https://agentmods.dev/skills/eric861129/skills_all-in-one/rails-expert"><img src="https://agentmods.dev/badge/skills/eric861129/skills_all-in-one/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/eric861129/skills_all-in-one/rails-expert"><img src="https://agentmods.dev/badge/skills/eric861129/skills_all-in-one/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 | $0.00104 | $0.01323 |
| Opus 5 | $0.00052 | $0.00661 |
| Sonnet 5 | $0.00021 | $0.00265 |
| Haiku 4.5 | $0.00010 | $0.00132 |
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 8d 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.
This is a copy
94% identical to rails-expert — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 155 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rails Expert
Core Workflow
- Analyze requirements — Identify models, routes, real-time needs, background jobs
- Scaffold resources —
rails generate model User name:string email:string,rails generate controller Users - Run migrations —
rails db:migrateand verify schema withrails db:schema:dump- If migration fails: inspect
db/schema.rbfor conflicts, rollback withrails db:rollback, fix and retry
- If migration fails: inspect
- Implement — Write controllers, models, add Hotwire (see Reference Guide below)
- Validate —
bundle exec rspecmust pass;bundle exec rubocopfor style- If specs fail: check error output, fix failing examples, re-run with
--format documentationfor detail - If N+1 queries surface during review: add
includes/eager_load(see Common Patterns) and re-run specs
- If specs fail: check error output, fix failing examples, re-run with
- Optimize — Audit for N+1 queries, add missing indexes, add caching
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 |
Common Patterns
N+1 Prevention with includes/eager_load
# BAD — triggers N+1
posts = Post.all
posts.each { |post| puts post.author.name }
# GOOD — eager load association
posts = Post.includes(:author).all
posts.each { |post| puts post.author.name }
# GOOD — eager_load forces a JOIN (useful when filtering on association)
posts = Post.eager_load(:author).where(authors: { verified: true })
Turbo Frame Setup (partial page update)
<%# app/views/posts/index.html.erb %>
<%= turbo_frame_tag "posts" do %>
<%= render @posts %>
<%= link_to "Load More", posts_path(page: @next_page) %>
<% end %>
<%# app/views/posts/_post.html.erb %>
<%= turbo_frame_tag dom_id(post) do %>
<h2><%= post.title %></h2>
<%= link_to "Edit", edit_post_path(post) %>
<% end %>
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.
- 8d ago First seen · 155 lines · 104 tokens per session scan A 1579515f3ad2
rails-expert is a skill published in the GitHub repository eric861129/SKILLS_All-in-one (52 stars, last pushed 4mo ago), licensed MIT. It adds 104 tokens to every session and 1,323 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to rails-expert, differing in 2 lines, and is treated as a copy.
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