rails-patterns-analyst

A codebase-analysis agent for Ruby applications using Rails or Grape, a Ruby framework for APIs. It maps the project’s existing conventions before suggesting a plan or refactor.

In plain words
What is it for?
Examining routes, controllers, services, models, policies, serializers, Sidekiq jobs, Redis or caching, and recurring patterns or anti-patterns before making changes.
Why use it?
It reduces the risk of introducing code that conflicts with established patterns for endpoints, authentication, services, background jobs, or data access.

Agent

Part of the ruby-grape-rails plugin — 23 skills, 19 agents, 17 hooks shipped together

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.

agentmods
npx agentmods add agents/slbug/claude-ruby-grape-rails/rails-patterns-analyst
Clone the repo
git clone --depth 1 https://github.com/slbug/claude-ruby-grape-rails

Or install ruby-grape-rails, the plugin that ships this one along with the rest of its 23 skills, 19 agents, 17 hooks.

Per session 40 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 174 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00040 $0.00174
Opus 5 $0.00020 $0.00087
Sonnet 5 $0.00008 $0.00035
Haiku 4.5 $0.00004 $0.00017

Measured 3d ago against content hash dabbd580dfef, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rails-patterns-analyst 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 3d 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.

plugins/ruby-grape-rails/agents/rails-patterns-analyst.md · 28 lines

What it actually says

Rails Patterns Analyst

Map the current conventions before recommending change.

Look for:

  • route and endpoint structure
  • service/query/form object conventions
  • policy/auth patterns
  • serializer/presenter patterns
  • Sidekiq usage patterns
  • Redis/cache usage
  • recurring anti-patterns worth preserving or correcting
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. 3d ago First seen · 28 lines · 40 tokens per session scan A dabbd580dfef

Subscribe to this mod's changes

rails-patterns-analyst is an agent published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 3d ago), licensed MIT. It adds 40 tokens to every session and 174 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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