ruby-style

A set of Ruby coding conventions aligned with the project's RuboCop configuration. RuboCop is a tool that checks Ruby code for agreed formatting and style rules.

In plain words
What is it for?
Use it when adding or editing Ruby code, choosing method arguments, handling missing hash keys, structuring controllers, and simplifying conditional logic.
Why use it?
It gives the coding agent consistent rules for writing and reviewing Ruby code, reducing style disagreements and common design problems.

Cursor rule for Cursor

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 rules/romkey/i2c-directory/ruby-style
Clone the repo
git clone --depth 1 https://github.com/romkey/I2C-Directory

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 254 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 $0.00000 $0.00254
Opus 5 $0.00000 $0.00127
Sonnet 5 $0.00000 $0.00051
Haiku 4.5 $0.00000 $0.00025

Measured yesterday against content hash e1347223fa26, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ruby-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 yesterday.

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.

.cursor/rules/ruby-style.mdc · 43 lines

What it actually says

Ruby Style

Follow the project's .rubocop.yml conventions:

  • Strings: Use single quotes unless interpolation is needed
  • Line length: Max 120 characters
  • Frozen string literal: Do not add # frozen_string_literal: true comments
  • Target Ruby: 3.3 — use modern Ruby syntax (pattern matching, endless methods where clear)
  • New cops: All new RuboCop cops are enabled

Patterns

  • Prefer Hash#fetch with defaults over Hash#[] when a missing key is possible
  • Use keyword arguments for methods with 3+ parameters
  • Keep controllers thin — extract logic to service objects or model methods
  • Use ActiveRecord::Enum for status fields
  • Guard clauses over nested conditionals
# ❌
def process(member)
  if member.active?
    if member.paid?
      do_work(member)
    end
  end
end

# ✅
def process(member)
  return unless member.active?
  return unless member.paid?

  do_work(member)
end
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. yesterday First seen · 43 lines · 0 tokens per session scan A e1347223fa26

Subscribe to this mod's changes

ruby-style is a cursor rule published in the GitHub repository romkey/I2C-Directory (11 stars, last pushed 21d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 254 tokens. 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.