What is rails-skills CLAUDE.md?

Project instructions for rails-skills, a collection of reusable coding-agent guides for Ruby on Rails development. A monorepo means one repository containing multiple related packages or projects; here, each guide has its own directory.

Use them when creating, editing, or reviewing skills under the skills directory, following the project template, or understanding how the Rails skill collection is organized.

They explain the repository’s structure, required guide format, reading order, and principles so new or changed Rails guides remain consistent.

How sandeepmvl/rails-skills configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to sandeepmvl/rails-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/sandeepmvl/rails-skills/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/sandeepmvl/rails-skills

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/sandeepmvl/rails-skills/claude-md/github.svg)](https://agentmods.dev/instructions/sandeepmvl/rails-skills/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/sandeepmvl/rails-skills/claude-md"><img src="https://agentmods.dev/badge/instructions/sandeepmvl/rails-skills/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/sandeepmvl/rails-skills/claude-md"><img src="https://agentmods.dev/badge/instructions/sandeepmvl/rails-skills/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,193 This file is loaded in full into every session.

When invoked 1,193 The same file — it is already loaded in full.

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.

Model	Per session	Once invoked
Fable 5.1	$0.01193	$0.01193
Opus 5	$0.00596	$0.00596
Sonnet 5	$0.00239	$0.00239
Haiku 4.5	$0.00119	$0.00119

Measured 11d ago against content hash 4df03bcabfce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

rails-skills CLAUDE.md 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.

CLAUDE.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

rails-skills — Project Context for Claude Code

You are helping build rails-skills: a production-grade pack of Claude Skills for Ruby on Rails developers. When installed, these skills make AI coding agents (Claude Code, Cursor, Codex, Gemini CLI, Windsurf, Antigravity) actually understand Rails conventions and stop generating un-Rails-like code.

Read these first, in order

This file — principles, conventions, quality bar
PLAN.md — what we're building, in what order, and what we are NOT building
skills/_TEMPLATE/SKILL.md — the skill template every new skill clones from
skills/00-rails-project-discovery/SKILL.md — the orchestrator skill (read to understand how skills route to each other)

What this repo is

A monorepo of independent Claude Skills, each in its own directory under skills/. Every skill follows the Anthropic Skills open standard (released December 2025). Skills are portable across Claude Code, Claude.ai, the Claude API, OpenAI Codex, Cursor, Gemini CLI, Antigravity, and Windsurf.

The canonical SKILL.md format (don't deviate)

skill-name/
├── SKILL.md          (required — YAML frontmatter + markdown body)
├── references/       (optional — deeper docs loaded only when needed)
├── scripts/          (optional — executable helpers, e.g. detection scripts)
└── assets/           (optional — code templates, config files)

YAML frontmatter is exactly two fields:

---
name: skill-name-in-kebab-case
description: One sentence on what it does AND when it should trigger. Be pushy about triggering — Claude tends to undertrigger skills. Example phrasings the user might say go here.
---

Body rules:

Under 500 lines. If you're approaching it, push detail into references/*.md and link to it.
Imperative voice ("Use find_by when..." not "You should consider using find_by").
Explain why, not just what. Senior Rails devs ignore rules without rationale.
Examples in before/after form wherever possible. AI agents learn from examples better than from rules.
Reference files have a TOC if over ~300 lines.

Read the full file on GitHub · 82 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.

11d ago First seen · 82 lines · 1,193 tokens per session scan A 4df03bcabfce

Subscribe to this mod's changes

rails-skills CLAUDE.md is an instructions file published in the GitHub repository sandeepmvl/rails-skills (21 stars, last pushed 3mo ago), licensed MIT. It adds 1,193 tokens to every session, about $0.0060 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 2026-08-30.

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AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

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vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

rails-skills: Instructions file for Claude Code