rails-style

rails-style is a skill for Claude Code, Codex from izkreny/agentifico. It costs 124 tokens per session (2,649 once invoked), scanned A, original, MIT.

A set of coding and review conventions based on common Rails practices associated with 37signals and DHH. Rails is a Ruby web framework, and these conventions cover areas such as models, controllers, routes, authorization, and dependencies.

In plain words
What is it for?
It is for building, refactoring, and reviewing Rails applications, including database models, request handling, routing, permissions, and framework dependencies.
Why use it?
It gives Rails work a consistent baseline for architecture, naming, object design, and safety decisions. Project-specific rules can override the defaults.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for building, refactoring, and reviewing Rails applications, including database models, request handling, routing, permissions, and framework dependencies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/izkreny/agentifico/rails-style
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.

Any agent
npx skills add izkreny/agentifico --skill rails-style
Clone the repo
git clone --depth 1 https://github.com/izkreny/agentifico

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 rails-style

README.md
[![agentmods](https://agentmods.dev/badge/skills/izkreny/agentifico/rails-style/github.svg)](https://agentmods.dev/skills/izkreny/agentifico/rails-style)
Your own site
<a href="https://agentmods.dev/skills/izkreny/agentifico/rails-style"><img src="https://agentmods.dev/badge/skills/izkreny/agentifico/rails-style/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.

agentmods 80×15 button for rails-style

Your own site · 80×15
<a href="https://agentmods.dev/skills/izkreny/agentifico/rails-style"><img src="https://agentmods.dev/badge/skills/izkreny/agentifico/rails-style.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 124 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,649 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00124 $0.02649
Opus 5 $0.00062 $0.01324
Sonnet 5 $0.00025 $0.00530
Haiku 4.5 $0.00012 $0.00265

Measured 9d ago against content hash 6df85e20dbe0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

rails-style 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 9d 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/rails-style/SKILL.md · 139 lines

How it starts

The opening of the file, as written. The whole thing — 139 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rails Style

The default baseline for Rails work. Distilled from 37signals codebases (Campfire, Fizzy) and DHH's review patterns. Sandi Metz's OOD guidance applies wherever it does not conflict with this file (small single-purpose classes and methods, depend on things that change less often than you do, isolate and name what varies, duck types over type checks); conflicts resolve in this file's favour.

Per-project overrides

Before applying this skill in a repository, read .agents/rails-style.md there if it exists. It records that project's deliberate deviations and committed-stack facts (a kept gem, a different authorization approach, front-end choices), and it wins on any conflict with this skill. Anything not listed there follows this skill's defaults. Never flag a recorded deviation as a violation.

References

Paths in this skill are relative to the file they appear in, inside the skill's own install directory; the one exception is .agents/rails-style.md above, which is relative to the repository being worked on. Deep domains live in references, loaded when the task touches them:

Core Defaults

  • Prefer clear, explicit code over clever abstractions. Abstractions must earn their keep; if you can't point to 3+ variations that need it, inline it.
  • Keep controllers thin and put domain behavior in models. No service objects, form objects, or decorators replacing straightforward model methods.
  • Prefer Rails conventions and built-ins before adding gems.
  • Model state and behavior with domain concepts, not ad-hoc flags.
  • Scope tenant/user data through ownership boundaries.
  • Favor database constraints for hard invariants; only validate in AR when you need user-facing error messages.
  • Keep interfaces small; don't add public methods that aren't used anywhere.
  • Prefer write-time computation over expensive read-time composition (counter caches, delegated types, precomputed roll-ups, dependent: :delete_all when no callbacks needed).
  • Use params.expect(...) for strong params.
  • Let it crash: bang methods (create!), handle exceptions at boundaries. Only use ! when a non-bang counterpart exists.
  • Fix root causes, not symptoms (e.g. enqueue_after_transaction_commit over retry logic for races).
  • YAGNI over defensive design: no guard for a case with no direct use today, no speculative parameter, no hook for an unscheduled future.
  • Ship tests in the same PR as behavior changes.

Read the full file on GitHub · 139 lines

Files

What ships with it

6 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.

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. 9d ago First seen · 139 lines · 124 tokens per session scan A 6df85e20dbe0

Subscribe to this mod's changes

rails-style is a skill published in the GitHub repository izkreny/agentifico (2 stars, last pushed yesterday), licensed MIT. It adds 124 tokens to every session and 2,649 once invoked, about $0.0006 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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