check-config-diff

name	check-config-diff
description	This skill should be used when the user asks to "check config diff", "compare upstream config", "diff rubocop config", "sync with Rails rubocop", or wants to see differences between the upstream Rails .rubocop.yml and this repository's config/rails.yml.
allowed-tools	WebFetch, Read

Diff Upstream RuboCop Config

Compare the upstream Rails RuboCop configuration with this repository's config/rails.yml.

Instructions

1. Fetch the upstream Rails RuboCop configuration from: https://raw.githubusercontent.com/rails/rails/main/.rubocop.yml
2. Read the local configuration from: config/rails.yml
3. Compare both configurations and report:
   • Cops/settings present in upstream but missing in local
   • Cops/settings present in local but missing in upstream
   • Cops/settings with different values between upstream and local
   • Note any intentional local additions (marked with comments like "Additional ... by rubocop-rails_config")

Output Format

Present the differences in a clear table or list format, grouped by category (AllCops, Layout, Style, Lint, Performance, Minitest, etc.).