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writing-skills Checked

Use when creating new skills, editing existing skills, or verifying skills work before deployment
✍️ Writing skills By obra Version v1.0.0 Added 2026-09-07 Updated 2026-09-07 Source ↗
8.4Overall rating
2Views
6Downloads
282.5kStars

Installation

🤖 Install via AI

Copy the prompt below and send it to your AI assistant (e.g. Claude Code) — it will follow the instructions and install automatically.

Install the "writing-skills" skill by following the instructions at https://skill123.me/install/writing-skills.
⌨️ Command line install

Run in your terminal — downloads and installs to ~/.claude/skills/.

curl -fsSL https://skill123.me/install/writing-skills.sh | bash
📦 Download ZIP

Download the zip and extract it into your skills directory (e.g. ~/.claude/skills/), then restart your session.

⬇ Download v1.0.0 · 40 KB
📊 Static rating
8.4/10
Trigger
7.0
Structure
7.3
Workflow
8.8
Content
9.0
Engineering
8.0
Security
10.0

Six-dimension rubric with reviewer rationale.

View scorecard ↓
🛡 Dynamic test
—

Not live-tested yet — this skill is rated on static analysis only.

About this skill

Use when creating new skills, editing existing skills, or verifying skills work before deployment

Writing Skills

Documentation

Use when creating new skills, editing existing skills, or verifying skills work before deployment

Writing Skills

Overview

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

**Personal skills live in your runtime's skills directory** (~/.claude/skills/ on Claude Code) — see codex-tools.md (../using-superpowers/references/codex-tools.md) or gemini-tools.md (../using-superpowers/references/gemini-tools.md) for the path on those runtimes. Codex, Copilot CLI, and Gemini CLI all also recognize ~/.agents/skills/ as a cross-runtime alias.

You write test cases (pressure scenarios with subagents), watch them fail (baseline behavior), write the skill (documentation), watch tests pass (agents comply), and refactor (close loopholes).

**Core principle:** If you didn't watch an agent fail without the skill, you don't know if the skill teaches the right thing.

**REQUIRED BACKGROUND:** You MUST understand superpowers:test-driven-development before using this skill. That skill defines the fundamental RED-GREEN-REFACTOR cycle. This skill adapts TDD to documentation.

**Official guidance:** For Anthropic's official skill authoring best practices, see anthropic-best-practices.md. This document provides additional patterns and guidelines that complement the TDD-focused approach in this skill.

What is a Skill?

A **skill** is a reference guide for proven techniques, patterns, or tools. Skills help future agents find and apply effective approaches.

**Skills are:** Reusable techniques, patterns, tools, reference guides

**Skills are NOT:** Narratives about how you solved a problem once

TDD Mapping for Skills

| TDD Concept | Skill Creation |

|-------------|----------------|

| **Test case** | Pressure scenario with subagent |

| **Production code** | Skill document (SKILL.md) |

| **Test fails (RED)** | Agent violates rule without skill (baseline) |

| **Test passes (GREEN)** | Agent complies with skill present |

| **Refactor** | Close loopholes while maintaining compliance |

| **Write test first** | Run baseline scenario BEFORE writing skill |

| **Watch it fail** | Document exact rationalizations agent uses |

| **Minimal code** | Write skill addressing those specific violations |

| **Watch it pass** | Verify agent now complies |

| **Refactor cycle** | Find new rationalizations → plug → re-verify |

The entire skill creation process follows RED-GREEN-REFACTOR.

When to Create a Skill

**Create when:**

  • Technique wasn't intuitively obvious to you
  • You'd reference this again across projects
  • Pattern applies broadly (not project-specific)
  • Others would benefit

**Don't create for:**

  • One-off solutions
  • Standard practices well-documented elsewhere
  • Project-specific conventions (put in your instructions file)
  • Mechanical constraints (if it's enforceable with regex/validation, automate it—save documentation for judgment calls)

Skill Types

View full documentation

### Technique

Concrete method with steps to follow (condition-based-waiting, root-cause-tracing)

### Pattern

Way of thinking about problems (flatten-with-flags, test-invariants)

### Reference

API docs, syntax guides, tool documentation (office docs)

Directory Structure


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

**Flat namespace** - all skills in one searchable namespace

**Separate files for:**

1. **Heavy reference** (100+ lines) - API docs, comprehensive syntax

2. **Reusable tools** - Scripts, utilities, templates

**Keep inline:**

  • Principles and concepts
  • Code patterns (< 50 lines)
  • Everything else

SKILL.md Structure

**Frontmatter (YAML):**

  • Two required fields: name and description (see agentskills.io/specification for all supported fields)
  • Max 1024 characters total
  • name: Use letters, numbers, and hyphens only (no parentheses, special chars)
  • description: Third-person, describes ONLY when to use (NOT what it does)
  • Start with "Use when..." to focus on triggering conditions
  • Include specific symptoms, situations, and contexts
  • **NEVER summarize the skill's process or workflow** (see SDO section for why)
  • Keep under 500 characters if possible

---
name: Skill-Name-With-Hyphens
description: Use when [specific triggering conditions and symptoms]
---

# Skill Name

## Overview
What is this? Core principle in 1-2 sentences.

## When to Use
[Small inline flowchart IF decision non-obvious]

Bullet list with SYMPTOMS and use cases
When NOT to use

## Core Pattern (for techniques/patterns)
Before/after code comparison

## Quick Reference
Table or bullets for scanning common operations

## Implementation
Inline code for simple patterns
Link to file for heavy reference or reusable tools

## Common Mistakes
What goes wrong + fixes

## Real-World Impact (optional)
Concrete results

Skill Discovery Optimization (SDO)

**Critical for discovery:** Future agents need to FIND your skill

### 1. Rich Description Field

**Purpose:** Your agent reads the description to decide which skills to load for a given task. Make it answer: "Should I read this skill right now?"

**Format:** Start with "Use when..." to focus on triggering conditions

**CRITICAL: Description = When to Use, NOT What the Skill Does**

The description should ONLY describe triggering conditions. Do NOT summarize the skill's process or workflow in the description.

**Why this matters:** Testing revealed that when a description summarizes the skill's workflow, an agent may follow the description instead of reading the full skill content. A description saying "code review between tasks" caused an agent to do ONE review, even though the skill's flowchart clearly showed TWO reviews (spec compliance then code quality).

When the description was changed to just "Use when executing implementation plans with independent tasks" (no workflow summary), the agent correctly read the flowchart and followed the two-stage review process.

**The trap:** Descriptions that summarize workflow create a shortcut agents will take. The skill body becomes documentation agents skip.


# ❌ BAD: Summarizes workflow - agents may follow this instead of reading skill
description: Use when executing plans - dispatches subagent per task with code review between tasks

# ❌ BAD: Too much process detail
description: Use for TDD - write test first, watch it fail, write minimal code, refactor

# ✅ GOOD: Just triggering conditions, no workflow summary
description: Use when executing implementation plans with independent tasks in the current session

# ✅ GOOD: Triggering conditions only
description: Use when implementing any feature or bugfix, before writing implementation code

**Content:**

  • Use concrete triggers, symptoms, and situations that signal this skill applies
  • Describe the *problem* (race conditions, inconsistent behavior) not *language-specific symptoms* (setTimeout, sleep)
  • Keep triggers technology-agnostic unless the skill itself is technology-specific
  • If skill is technology-specific, make that explicit in the trigger
  • Write in third person (injected into system prompt)
  • **NEVER summarize the skill's process or workflow**

# ❌ BAD: Too abstract, vague, doesn't include when to use
description: For async testing

# ❌ BAD: First person
description: I can help you with async tests when they're flaky

# ❌ BAD: Mentions technology but skill isn't specific to it
description: Use when tests use setTimeout/sleep and are flaky

# ✅ GOOD: Starts with "Use when", describes problem, no workflow
description: Use when tests have race conditions, timing dependencies, or pass/fail inconsistently

# ✅ GOOD: Technology-specific skill with explicit trigger
description: Use when using React Router and handling authentication redirects

### 2. Keyword Coverage

Use words an agent would search for:

  • Error messages: "Hook timed out", "ENOTEMPTY", "race condition"
  • Symptoms: "flaky", "hanging", "zombie", "pollution"
  • Synonyms: "timeout/hang/freeze", "cleanup/te

Score breakdown

Trigger
7.0
Use-when description with create/edit/verify triggers; brief, no When-Not and modest keyword breadth.
Structure
7.3
679-line SKILL.md with supporting docs and a js tool at root level instead of references/ and scripts/ folders.
Workflow
8.8
Excellent task design: baseline testing, rationalization tables, micro-test wording protocol, per-type test matrix and mandatory deployment checklist.
Content
9.0
Precise imperative writing with bad/good contrasts and concrete command examples.
Engineering
8.0
Valid frontmatter and executable render-graphs.js; the ../using-superpowers reference path does not exist in this package.
Security
10.0
render-graphs.js only shells out to local graphviz dot; no network, no secrets, no injection.
Mature TDD-for-skills authoring guide with strong RED-GREEN-REFACTOR methodology, checklists and testing-by-type matrix; structure is flat (root-level docs and tool) and references a sibling skill path that breaks in standalone packaging.