writing-skills

# Writing Skills

**REQUIRED BACKGROUND:** Read ed3d-extending-claude:writing-claude-directives for foundational guidance on token efficiency, discovery optimization, and compliance techniques. This skill focuses on TDD methodology specific to skill creation.

## Core Principle

**Writing skills IS Test-Driven Development applied to process documentation.**

Write test cases (pressure scenarios), watch them fail (baseline behavior), write the skill, watch tests pass, refactor (close loopholes).

**Iron Law:** No skill without a failing test first. Same as TDD for code.

## TDD Mapping

| TDD Concept | Skill Creation |
|-------------|----------------|
| Test case | Pressure scenario with subagent |
| Production code | SKILL.md document |
| RED | Agent violates rule without skill |
| GREEN | Agent complies with skill present |
| Refactor | Close loopholes, re-test |

## When to Create a Skill

**Create when:**
- Technique wasn't intuitively obvious
- You'd reference this across projects
- Pattern applies broadly
- Others would benefit

**Don't create for:**
- One-off solutions
- Standard practices documented elsewhere
- Project-specific conventions (use CLAUDE.md)

## Skill Types

**Technique:** Concrete method with steps (condition-based-waiting, root-cause-tracing)

**Pattern:** Mental model for problems (flatten-with-flags, test-invariants)

**Reference:** API docs, syntax guides, tool documentation

## Directory Structure

```
skills/
  skill-name/
    SKILL.md              # Main reference (required)
    supporting-file.*     # Only if needed
```

**Separate files for:** Heavy reference (100+ lines), reusable tools/scripts

**Keep inline:** Principles, code patterns (<50 lines), everything else

## SKILL.md Template

```markdown
---
name: Skill-Name-With-Hyphens
description: Use when [triggers/symptoms] - [what it does, third person]
---

# Skill Name

## Overview
Core principle in 1-2 sentences.

## When to Use
Symptoms and use cases. When NOT to use.

## Core P