A setup workflow for a Ruby, Rails, and Grape development add-on that detects the project stack and records project-specific notes in CLAUDE.md.

Use it when first configuring the add-on or updating its project notes so later planning, coding, checking, and review follow the repository's setup.

It gives the coding agent the context it needs about the project's queues, database layer, and folder structure.

rb:init — Skill for Claude Code by slbug/claude-ruby-grape-rails

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add slbug/claude-ruby-grape-rails

Claude Code

/plugin install ruby-grape-rails

Made for: Claude Code.

Or install ruby-grape-rails, the plugin that ships this one along with the rest of its 52 skills, 19 agents, 17 hooks.

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/skills/slbug/claude-ruby-grape-rails/init/github.svg)](https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/init)

Your own site

<a href="https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/init"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/init/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/skills/slbug/claude-ruby-grape-rails/init"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/init.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,575 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. 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	$0.00045	$0.04575
Opus 5.5	$0.00018	$0.01830
Sonnet 5.5	$0.00009	$0.00915
Haiku 4.5	$0.00005	$0.00458

Measured 15d ago against content hash 996dcbcae089, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

rb:init scanned grade B with 1 finding 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 15d 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

in `~/.claude/settings.json`:

plugins/ruby-grape-rails/skills/init/SKILL.md · 349 lines

How it starts

The opening of the file, as written. The whole thing — 349 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plugin Initialization

Write a managed block of project-specific stack notes into the project's memory file (CLAUDE.local.md when usable, else CLAUDE.md or AGENTS.md — see "Target File"). Do NOT write Iron Laws or Advisory Preferences into it — inject-rules.sh delivers them at runtime on SessionStart + SubagentStart.

Block-reach contract:

Consumer	Sees managed block?
Main session (interactive Claude)	YES
Subagent spawned WITHOUT `omitClaudeMd: true`	YES
Specialist subagent with `omitClaudeMd: true` (most reviewers/analyzers)	NO — relies on `inject-rules.sh` SubagentStart for Iron Laws + Preferences only; no stack notes

Plan the block content for main-session skill bodies (/rb:plan, /rb:review, /rb:verify, /rb:work). Do NOT inject content needed by specialist subagents into this block; surface it through their per-agent prompt or the inject-rules.sh runtime payload.

Usage

/rb:init — Fresh install
/rb:init --update — Update existing managed block

Detect the Stack

Check the project before writing anything.

Detection rules:

Always run ${CLAUDE_PLUGIN_ROOT}/bin/detect-stack first.
Prefer exact *_VERSION values from that script when writing the managed-block header.
Use plain detected only as a last resort when a direct gem is present but no resolved lockfile version is available.
Never use broad substring regexes like /rails $([^)]+)$/ against raw Gemfile.lock; they can falsely match gems such as rubocop-rails.
Read these detector keys before deciding what ORM/package guidance to inject:
- ORM: DETECTED_ORMS, PRIMARY_ORM
- Rails shape: RAILS_COMPONENTS, FULL_RAILS_APP
- Ruby: RUBY_VERSION (placeholder source). INTERPRETER_RUBY_VERSION is informational only — emitted when interpreter differs from project pin.
- Packages: PACKAGE_LAYOUT, PACKAGE_LOCATIONS, HAS_PACKWERK, PACKAGE_QUERY_NEEDED
If PACKAGE_QUERY_NEEDED=true, ask the user: No Packwerk detected. Do you have something similar implemented? Provide modules/packages location and their stack/ORM.
If DETECTED_ORMS contains BOTH active_record AND sequel (mixed-ORM repo), run the MIXED_ORM_SECTION interview (per ${CLAUDE_SKILL_DIR}/references/conditional-sections.md § "MIXED_ORM_SECTION") regardless of PACKAGE_QUERY_NEEDED value. detect-stack does NOT emit per-package ORM ownership — interview is the only source. Skip when only one ORM detected.
Do not reimplement stack detection inline in chat or ad-hoc Ruby snippets. detect-stack is the source of truth.
If ${CLAUDE_PLUGIN_ROOT}/bin/detect-stack is missing or fails, STOP and explain that plugin stack detection is unavailable instead of inventing a fallback parser.

Read the full file on GitHub · 349 lines

Files

What ships with it

3 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.

15d ago Changed · +13 lines 996dcbcae089
1mo ago Changed · +52 lines · -3 tokens per session e7275178483b
1mo ago First seen · 284 lines · 48 tokens per session scan B e0a3d56cd0e6

Subscribe to this mod's changes

rb:init is a skill published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 16d ago), licensed MIT. It adds 45 tokens to every session and 4,575 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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rb:init