brand-guidelines, has one of each kind of file a skill can carry. Select a file to read what it's for and see a minimal example.expense-reports, has one of each file that chat, Cowork, and Claude Code all load, plus the README and license the directory requires. Select a file to read what it’s for and see a minimal example.The one required file. Its frontmatter names and describes the skill, and Claude reads the description to decide when the skill applies. The body holds the instructions Claude follows once it does.
In this example, the skill applies Acme's brand guidelines and tells Claude where the supporting files are:
```markdown SKILL.md theme={null} --- name: brand-guidelines description: Apply Acme Corp brand guidelines to presentations and documents, including official colors, fonts, and logo usage. --- Use these guidelines whenever you produce a document or deck for Acme. 1. Use the colors and fonts in the sections below. 2. For wording, follow `references/voice-and-tone.md`. 3. For slides, start from `assets/slide-template.md`. 4. Before you finish, run `python3 ${CLAUDE_SKILL_DIR}/scripts/check_contrast.py` on any color pairs you chose. ```Longer background that Claude reads only when a step calls for it, so it doesn't crowd SKILL.md. Mention the file by path at the step where Claude needs it.
In this example, the file holds the writing rules the instructions point to in step 2:
```markdown references/voice-and-tone.md theme={null} # Voice and tone - Write in the second person and the present tense. - Prefer short sentences. Avoid exclamation marks. - Product names are always capitalized: Acme Cloud, Acme Sync. ```Templates, images, and data files that Claude copies or fills in rather than reads for guidance.
In this example, the asset is the slide outline that step 3 tells Claude to start from:
```markdown assets/slide-template.md theme={null} # [Deck title] ## Agenda ## [Section 1] ## [Section 2] ## Next steps ```Code that Claude runs while following the skill, for work that is more reliable as a program than as instructions. Reference it from `SKILL.md` with `${CLAUDE_SKILL_DIR}` so the path resolves wherever the skill is installed.
In this example, the script checks that a text and background color pair has enough contrast:
```python scripts/check_contrast.py theme={null} import sys def luminance(hex_color): r, g, b = (int(hex_color[i:i+2], 16) / 255 for i in (1, 3, 5)) f = lambda c: c / 12.92 if c <= 0.03928 else ((c + 0.055) / 1.055) ** 2.4 return 0.2126 * f(r) + 0.7152 * f(g) + 0.0722 * f(b) fg, bg = sys.argv[1], sys.argv[2] l1, l2 = sorted((luminance(fg), luminance(bg)), reverse=True) ratio = (l1 + 0.05) / (l2 + 0.05) print(f"{ratio:.2f}", "OK" if ratio >= 4.5 else "LOW") ```