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 igmarin/rails-agent-skills --skill apply-stack-conventionsgit clone --depth 1 https://github.com/igmarin/rails-agent-skillsWrote 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/igmarin/rails-agent-skills/apply-stack-conventions)<a href="https://agentmods.dev/skills/igmarin/rails-agent-skills/apply-stack-conventions"><img src="https://agentmods.dev/badge/skills/igmarin/rails-agent-skills/apply-stack-conventions/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/igmarin/rails-agent-skills/apply-stack-conventions"><img src="https://agentmods.dev/badge/skills/igmarin/rails-agent-skills/apply-stack-conventions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00049 | $0.01547 |
| Opus 5 | $0.00024 | $0.00773 |
| Sonnet 5 | $0.00010 | $0.00309 |
| Haiku 4.5 | $0.00005 | $0.00155 |
Grade A, and why
apply-stack-conventions 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.
How it starts
The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Apply Stack Conventions
Quick Reference
| Stack area | Default convention |
|---|---|
| Rails MVC | Thin controllers; move non-trivial business logic into service objects |
| PostgreSQL | Avoid N+1s with includes; use database constraints for integrity |
| Hotwire | Prefer Turbo Frames/Streams before Stimulus; only reach for Stimulus when Turbo cannot handle the interactivity |
| Tailwind | Use utilities in views; extract repeated UI into partials/components |
| Auth | Apply Devise authentication and Pundit authorization to every action that touches access-controlled resources |
HARD-GATE: TDD Cycle
All new code must have its test written and validated before implementation. Follow this exact cycle for every layer:
- Write the spec file — show the full file content, not only the path
- Run:
bundle exec rspec spec/[path]_spec.rb— verify it FAILS (Observed RED output) - Write the implementation code
- Re-run the same command — verify it PASSES (Observed GREEN output)
- Refactor if needed, keeping tests green
CRITICAL: Execute all test commands using your shell/terminal tools. Do not fabricate, mock, or simulate terminal output. Copy-paste the actual observed output. If the environment does not support running tests, stop and tell the user — do not proceed to implementation without verified RED output.
Red-Green Cycle Example
Spec file — spec/models/order_spec.rb
require 'rails_helper'
RSpec.describe Order, type: :model do
describe 'validations' do
it 'is invalid without a total' do
order = build(:order, total: nil)
expect(order).not_to be_valid
expect(order.errors[:total]).to include("can't be blank")
end
end
end
Run command
bundle exec rspec spec/models/order_spec.rb
Observed RED output — paste actual terminal output here (expect failure)
Model implementation — app/models/order.rb
class Order < ApplicationRecord
validates :total, presence: true
end
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.
- assets/snippets/eager_loading.rb 185 B runs code
- assets/snippets/n_plus_one_fix_example.rb 187 B runs code
- assets/snippets/service_object.rb 227 B runs code
- assets/snippets/stimulus_controller.js 185 B runs code
- assets/snippets/tailwind_component.html.erb 197 B
- assets/snippets/turbo_frame.html.erb 102 B
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 · 147 lines · 49 tokens per session scan A 99552a07cdca
apply-stack-conventions is a skill published in the GitHub repository igmarin/rails-agent-skills (24 stars, last pushed 18d ago), licensed MIT. It adds 49 tokens to every session and 1,547 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 2026-08-30.
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