Спеціально для каналу Сашко пише код
Chapter 02 · Reference implementation

Claude Skills.
The gold standard.

Folders containing a SKILL.md file — YAML frontmatter with metadata, and a Markdown body with actual instructions.

The frontmatter

Two required fields. Both strict.

🏷️

name

Limited to 64 characters, lowercase with hyphens. It cannot contain "anthropic" or "claude".

📝

description

Capped at 1,024 characters. Should describe both what the skill does and when to use it, written in third person.

---
name: react-component-review
description: Reviews React components for prop typing, naming, and
  styling conventions. Use when creating or editing files under
  src/components, or when the user mentions React, JSX, or TSX.
---

# When reviewing React components, verify typed props, named exports, and Tailwind-only styling...
The breakthrough

Progressive disclosure — three levels of loading.

Three loading tiers keep the context window clean: metadata is always present, the body loads only when the skill triggers, and bundled files are read on demand.

Level 1
Metadata (name + description)
Loaded at startup — so Claude knows the skill exists.
~100 tokens / skill
Level 2
SKILL.md body
Loaded only when the skill triggers based on the conversation.
under 5K tokens
Level 3
Bundled files & scripts
Only pulled in if Claude explicitly reads them on demand.
effectively unlimited
Three surfaces

Skills work across the Claude ecosystem.

🌐

Claude.ai (web)

Supports ZIP uploads in Settings — for Pro, Max, Team, and Enterprise plans.

💻

Claude Code (CLI)

Uses filesystem-based skills in ~/.claude/skills/ (personal) or .claude/skills/ (project).

🔌

Claude API

Requires three beta headers and does not sync across surfaces.

Beyond programming

Skills ship for document creation too.

Anthropic ships several built-in skills for handling Office documents — source-available in the anthropics/skills GitHub repo.

📄

docx · Word

Generate a formatted meeting-notes document from a chat transcript, or rewrite a contract template with clause substitutions.

📊

xlsx · Excel with charts

Turn a CSV of sales data into a workbook with pivot tables and a monthly-revenue chart ready to share with stakeholders.

🎞️

pptx · PowerPoint

Draft a pitch deck with branded title slide, section headers, and speaker notes — directly from a product one-pager.

📕

pdf · generate & extract

Extract tabular data from an invoice PDF, fill a tax form with user-provided values, or merge multiple reports into one file.

🧪

skill-creator · meta-skill

Scaffolds a new skill: asks you for a name and description, produces a valid SKILL.md, and lints the frontmatter.