skills/
└── topic-best-practices/
    ├── SKILL.md              # Main summary with all rules
    └── rules/
        ├── rule-name.md      # Detailed individual rules
        └── another-rule.md

---
name: topic-best-practices
description: When to use this skill.
---

# Topic Best Practices

Brief intro. Contains N rules across M categories.

## When to Apply

- Situation 1
- Situation 2

## Rules Summary

### Category (IMPACT)

#### rule-name - @rules/rule-name.md

One sentence. Code example.

---
title: Rule Title
impact: HIGH
tags: [relevant, tags]
---

# Rule Title

What to do and why.

## Why

- Benefit 1
- Benefit 2

## Pattern

\`\`\`ruby
# Bad
bad_code

# Good
good_code
\`\`\`

## Rules

1. Takeaway 1
2. Takeaway 2

# Bad: Too abstract
"Keep your code organized."

# Good: Concrete
"Place concerns in `app/models/model_name/` not `app/models/concerns/`."

\`\`\`ruby
# Shows exactly what to do
app/models/card/closeable.rb
\`\`\`

## Why

- **Testability**: Sync method can be tested without job infrastructure
- **Flexibility**: Callers choose sync or async based on context
- **Clarity**: The `_later` suffix makes async behavior explicit

# Bad
---
Here is an overview of the key points:
---

# Good
Group related rules by category. Each rule gets a one-sentence
description and a short code example.