applying-code-principles

# Code Principles

## Priority Order

| Priority | Principle     | When to Apply                                  |
| -------- | ------------- | ---------------------------------------------- |
| 1        | Safety First  | Security, data integrity                       |
| 2        | YAGNI         | Don't build what you don't need                |
| 3        | Occam's Razor | Simplest solution                              |
| 4        | SOLID         | For complex systems                            |
| 5        | DRY           | Eliminate duplication (not at cost of clarity) |
| 6        | Miller's Law  | Respect 7±2 cognitive limit                    |

## Quick Checks

See CLAUDE.md Development Checks section (always loaded, single source of truth).

## Thresholds

| Target        | Ideal | Max | Limit |
| ------------- | ----- | --- | ----- |
| Function args | 3     | 5   | 7     |
| Class methods | 5     | 7   | 9     |
| Conditionals  | 3     | 5   | 7     |

## Rules

| Principle | Rule                                           |
| --------- | ---------------------------------------------- |
| DRY       | Abstract on 3rd duplication (Rule of Three)    |
| SOLID     | Interface only when 2nd implementation appears |
| YAGNI     | Build only if problem exists now               |
| Readable  | New team member understands in < 1 minute      |