skills/context/rails-context-engineering/SKILL.md
Use before writing code, tests, or PRDs in a Rails project to load the minimum context needed to make correct decisions. Inspects `db/schema.rb`, `config/routes.rb`, neighboring models, factories, specs, engine boundaries, and `Gemfile.lock` to surface existing patterns, naming conventions, and gotchas. Produces a concise context summary before any code is proposed, and a confusion-management block when requirements are ambiguous or specs and code have drifted. Trigger words: load context, gather context, context engineering, read the code first, before I code, existing patterns, project conventions, where is this defined, ambiguous requirements, spec vs code drift, unclear spec, missing requirements, what does the codebase already use, match existing style.
npx skillsauth add igmarin/rails-agent-skills rails-context-engineeringInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Load minimum context before any code, spec, or PRD in an existing Rails codebase. A fifteen-second read of db/schema.rb, config/routes.rb, and one neighbor saves a full retry.
DO NOT propose code, specs, PRDs, or task lists until the Context Summary is posted.
DO NOT silently resolve ambiguity — if requirements conflict or specs and code disagree, post a Confusion Block first.
DO NOT load the entire repo — use targeted reads (schema, routes, one neighbor of each kind).
ALWAYS cite the files you read (path:line where possible) so the user can verify.
ALWAYS re-check context when the user's request changes scope mid-conversation.
db/schema.rb — tables and columns involved (grep by table name)config/routes.rb — routes that border the changeGemfile.lock — confirm Rails version + domain gems (sidekiq, pundit, rspec, rails-i18n, graphql, etc.)grep -r "class.*Controller" app/controllers, grep -r "class.*Service" app/services, etc.### Confusion Block
- Conflict: <what conflicts — e.g., spec asserts X but code does Y>
- Options: <list the options with their tradeoffs>
- Recommendation: <state which option and why, or ask user to choose>
Do not pick silently.
7. Hand off: With context loaded, proceed to the next skill (create-prd, generate-tasks, rails-tdd-slices, rails-stack-conventions, etc.). The Context Summary travels with the task.
Every invocation of this skill MUST produce a Context Summary in this exact shape, before any code or spec is proposed:
### Context Summary
- Scope: <one line — Rails layer and nearest class/file area>
- Rails version: <from Gemfile.lock>
- Relevant tables: <table names from db/schema.rb, columns that matter>
- Relevant routes: <resource/member routes from config/routes.rb>
- Nearest pattern: <path:line — one existing file that solves a similar problem>
- Nearest spec: <path:line — existing spec for this area (or NONE)>
- Engine boundary: <engine name or N/A>
- Gotchas: <domain gem quirks, enum mappings, polymorphic edges, counter caches, soft-delete, single-table inheritance — only list if present>
- Confusion: <NONE, or a one-line pointer to the Confusion Block below>
Additional MUSTs:
Context loaded. Next: <skill-name> — <one-line reason>.| Pitfall | What to do |
|---------|------------|
| Generic "the model, the controller" language | Name the class and file — generic language is the symptom of skipped context |
| Citing paths without line numbers | Use path:line when referencing a method, class, or association |
| Ignoring engine boundaries | Name the engine and its host integration points when a mounted engine is touched |
| Ignoring spec/code drift | A passing stale spec is worse than a missing spec — call it out in Confusion |
| Skill | When to chain | |-------|---------------| | create-prd / generate-tasks | Before scoping a PRD or breaking down tasks on an existing feature area | | rails-tdd-slices | Nearest spec in the summary usually reveals the right first failing spec | | rails-bug-triage / refactor-safely | Context precedes reproduction or characterization tests | | rails-architecture-review / ddd-ubiquitous-language | When context reveals boundary or naming drift |
development
Entry point for Rails development workflows covering TDD, RSpec, Service Objects, DDD, GraphQL, Engines, and Code Quality. Use when the user asks about Ruby on Rails development patterns, needs RSpec test suites generated, wants service objects scaffolded, is setting up GraphQL schemas, performing Rails code review, refactoring .rb files, working with domain-driven design, implementing background jobs, conducting Rails security checks, or building Rails engines. Generates RSpec tests, structures service objects, enforces TDD workflows, configures GraphQL schemas, and coordinates domain-driven design patterns. Trigger keywords: Rails, RSpec, TDD, Rails testing, Rails refactor, Rails API, Rails code review, domain driven design, service objects, GraphQL, Rails engine, Ruby, .rb, background jobs, Rails migrations, Rails security check.
development
Use when shipping a Rails engine gem — FIRST run full test suite (`bundle exec rspec`) and fix ALL failures, verify gemspec metadata and dependencies match tested Rails/Ruby versions, dry-run: `gem build *.gemspec && gem push --dry-run *.gem` and verify contents, generate CHANGELOG.md organized by category (added/changed/deprecated/removed/fixed), produce step-by-step upgrade notes with before/after code, set semantic version in `lib/[engine_name]/version.rb`, document deprecations with migration paths, load release assets conditionally and state which one informed the output. Trigger words: version bump, changelog, deprecation, gemspec, upgrade, release, publish gem, ship gem.
development
Orchestrates the full Rails TDD cycle with hard gates: test MUST exist, be run, and FAIL for the correct reason (e.g. undefined method, not syntax error) before any implementation code — propose minimal implementation and wait for user approval → verify test PASSES → run full suite with rubocop, brakeman, rspec all green → produce YARD documentation and self-reviewed PR; phases context/test design→implementation→iterate→finish. Use when practicing test-driven development, red-green-refactor, TDD workflow, writing tests before code, adding tests first, or building a Rails feature where specs must gate implementation.
development
Complete Rails project setup loop with hard gates: verify Ruby version matches .ruby-version, Bundler installed, database connection successful, all env vars loaded, and ALL external CI actions pinned to immutable commit SHAs (never mutable tags like @v4) → configure CI/CD pipeline with linting, testing, and security scanning → validate end-to-end with bundle install, db:create, db:migrate, rspec, and write SETUP_CHECKLIST.md; phases context/onboarding→CI/CD configuration→environment validation. Use when starting a new Rails project, running `rails new`, configuring a Gemfile or .ruby-version, setting up a development environment, or wiring up CI/CD for a Ruby on Rails app. Trigger: setup project, new Rails app, configure CI/CD, dev environment setup, rails new, Gemfile setup, .ruby-version, Ruby on Rails project bootstrap.