The Complete Guide to Building Skills for Claude (Without Reading 33 Pages)

If you've ever wished Claude could remember your workflow, follow your team's style guide, or execute a multi-step process without being re-explained every time — skills are the answer.

A skill is a simple folder you upload to Claude that teaches it how to handle a specific task, consistently, across every conversation. Instead of coaching Claude from scratch each time, you teach it once and it applies that knowledge automatically whenever it's relevant.

This guide distills Anthropic's full 33-page documentation into everything that actually matters.

What Makes Skills Powerful

Skills work best when you have something repeatable: generating documents in your brand style, running sprint planning sessions, onboarding new customers, or orchestrating multi-step workflows across tools like Notion, Linear, or Figma.

They also work exceptionally well when paired with MCP (Model Context Protocol) integrations. Think of it this way:

MCP is the kitchen. Skills are the recipes.

MCP gives Claude access to your tools and data. Skills tell Claude how to use them — the right order, the right checks, the right output format. Without skills, users connect your MCP integration and stare at a blank screen. With skills, workflows activate automatically.

The Anatomy of a Skill

Every skill is a folder containing four possible elements:

your-skill-name/
├── SKILL.md        ← Required. The brain of your skill.
├── scripts/        ← Optional. Python, Bash, etc.
├── references/     ← Optional. Docs, guides, examples.
└── assets/         ← Optional. Templates, fonts, icons.

One hard rule: the main file must be named exactly SKILL.md — case-sensitive, no variations. The folder itself must use kebab-case (e.g., my-skill-name, never My Skill Name).

How Claude Decides to Use Your Skill

Claude doesn't load every skill into memory at once. It uses a smart three-level system:

Level 1 — YAML Frontmatter: Always present in Claude's system prompt. This is how Claude decides whether your skill is relevant.

Level 2 — SKILL.md body: Full instructions, loaded only when Claude determines the skill applies.

Level 3 — Linked files: Additional references loaded only as needed.

This means one thing above all else: your frontmatter description is everything. If Claude doesn't understand when to use your skill from that description, the rest doesn't matter.

Building Your First Skill

Step 1: Define your use cases first

Before writing a single line, get clear on:

What does the user want to accomplish?
What multi-step workflow does this require?
What domain knowledge or tools are involved?

A good use case looks like this:

Use Case: Sprint Planning
Trigger: User says "help me plan this sprint"
Steps: Fetch project status → Analyze capacity 
       → Suggest prioritization → Create tasks in Linear
Result: Fully planned sprint, zero manual setup

Step 2: Write the YAML frontmatter

This is the most critical part of your entire skill. The minimal required format:

---
name: your-skill-name
description: What it does. Use when user asks to [specific phrases].
---

Your description must do two things: explain what the skill does and specify when to trigger it. Include actual phrases users would say. Keep it under 1,024 characters. Never use XML < > tags.

The difference between a skill that works and one that doesn't:

# ✅ Works — specific, includes real trigger phrases
description: Analyzes Figma design files and generates developer 
handoff documentation. Use when user uploads .fig files, asks for 
"design specs", "component documentation", or "design-to-code handoff".

# ❌ Doesn't work — too vague, no triggers
description: Helps with projects.

Step 3: Write the instructions

After the frontmatter, write your instructions in plain Markdown. Structure them like this:

# Skill Name

## Instructions

### Step 1: [Action]
Specific, actionable description. Not "validate the data" — 
write "Run python scripts/validate.py --input {filename}".

## Examples
User says: "set up a new project"
1. Fetch existing projects via MCP
2. Create with provided parameters
Result: Project created with confirmation link

## Troubleshooting
Error: Connection refused
Cause: MCP server not running
Fix: Settings > Extensions > Reconnect

Keep the main SKILL.md under 5,000 words. Move detailed documentation into the references/ folder and link to it — Claude will load it only when needed.

The 3 Skill Categories (with Real Examples)

Category 1: Document & Asset Creation For generating consistent, high-quality outputs — reports, presentations, UI designs, code.

Real examples from Anthropic's library: frontend-design, docx, pptx, xlsx skills.

Embed style guides, output templates, and quality checklists. No external tools required.

Category 2: Workflow Automation For multi-step processes that need consistent methodology every time.

Real example: The skill-creator skill — walks users through building a new skill interactively.

Embed ordered steps, validation gates between stages, and iterative refinement loops.

Category 3: MCP Enhancement For turning raw tool access into reliable, guided workflows.

Real example: Sentry's sentry-code-review skill — automatically analyzes and fixes bugs in GitHub PRs using Sentry's error monitoring data via MCP.

Embed domain expertise, sequenced MCP calls, and error handling users would otherwise need to figure out themselves.

5 Patterns That Actually Work

Pattern 1: Sequential Workflow Orchestration

Best for: ordered multi-step processes where sequence matters.

Create Account → Setup Payment → Create Subscription → Send Welcome Email

Key techniques: explicit step ordering, dependencies between steps, rollback instructions for failures.

Pattern 2: Multi-MCP Coordination

Best for: workflows that span multiple services.

Figma MCP: Export assets
Drive MCP: Upload & organize
Linear MCP: Create dev tasks
Slack MCP: Post handoff summary

Key techniques: clear phase separation, explicit data passing between services, centralized error handling.

Pattern 3: Iterative Refinement

Best for: outputs that improve with review cycles.

Draft → Validate → Refine → Re-validate → Finalize

Key techniques: explicit quality criteria, validation scripts, defined stopping conditions.

Pattern 4: Context-Aware Tool Selection

Best for: same goal, different tools depending on context.

File > 10MB?        → Cloud Storage MCP
Collaborative doc?  → Notion MCP  
Code file?          → GitHub MCP

Key techniques: clear decision criteria, fallback options, transparency with the user about why a tool was chosen.

Pattern 5: Domain-Specific Intelligence

Best for: adding specialized knowledge beyond what tool access alone provides.

Financial compliance example:

Check sanctions list → Verify jurisdiction → Assess risk 
→ Process payment → Log full audit trail

Key techniques: compliance checks before action, embedded domain rules, comprehensive documentation.

How to Test Your Skill

Triggering tests — Run 10–20 queries that should activate your skill. Aim for 90% automatic activation. Also verify it doesn't trigger on unrelated topics.

Best debugging trick: Ask Claude directly — "When would you use the [skill name] skill?" It will quote the description back at you. Gaps become immediately obvious.

Functional tests — Verify outputs are correct, API calls succeed, and edge cases are handled.

Performance comparison — Measure the before and after:

Metric	Without Skill	With Skill
Messages to complete task	15	2
Failed API calls	3	0
Tokens consumed	12,000	6,000

When Things Go Wrong

Symptom	Fix
"Could not find SKILL.md" on upload	Rename exactly `SKILL.md` — case-sensitive
"Invalid frontmatter" error	Check `---` delimiters; close all quotes
Skill never loads automatically	Add real trigger phrases to description
Skill loads for unrelated queries	Add "Do NOT use for..." to description
MCP calls fail	Test MCP independently first; check tool names are case-exact
Claude ignores the instructions	Use `CRITICAL:` headers; move key steps to the top
Slow or degraded responses	Move docs to `references/`; keep `SKILL.md` under 5,000 words

Distributing Your Skill

For individual use: Zip the folder → Claude.ai → Settings → Capabilities → Skills → Upload.

For your organization: Admins can deploy skills workspace-wide with automatic updates and centralized management.

For the community: Host on GitHub. Write a README in the repo root — never inside the skill folder itself. When describing your skill externally, lead with outcomes:

✅ "Set up a complete project workspace in seconds instead of 30 minutes"
❌ "A folder containing YAML frontmatter and Markdown instructions"

Your Pre-Upload Checklist

[ ] Folder named in kebab-case
[ ] File named exactly SKILL.md
[ ] YAML wrapped in --- delimiters top and bottom
[ ] name field: kebab-case, no spaces, no capitals
[ ] description explains what AND when
[ ] No XML < > tags anywhere in the file
[ ] Instructions are specific, not vague
[ ] Error handling included
[ ] Tested on direct AND paraphrased trigger phrases
[ ] Confirmed no false triggers on unrelated queries

Build Your First Skill in 15 Minutes

The fastest path from zero to working skill:

Open Claude.ai and say: "Use the skill-creator skill to help me build a skill for [your use case]"
Describe your top 2–3 workflows
Let skill-creator generate your SKILL.md with proper frontmatter
Upload and run trigger tests
Iterate based on what fires and what doesn't

Most people have a working skill within 15–30 minutes following this path.

The Bottom Line

Skills are reusable expertise. You encode your workflow preferences, domain knowledge, and best practices into Claude once — and every conversation benefits from it automatically.

The investment is small: a well-written SKILL.md. The return is significant: consistent outputs, less re-explaining, fewer corrections, and an AI assistant that actually works the way you work.

Start with one use case. One workflow. Ship it, test it, improve it.

Based on Anthropic's "The Complete Guide to Building Skills for Claude" (2026)

Write your own skill

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The Complete Guide to Building Skills for Claude (Without Reading 33 Pages)