Introduction
Two weeks ago we explained what Claude Agent Skills are: reusable instruction packs that turn Claude into a specialist for your business. Today we go hands-on — and you don’t need to write a single line of code.
If you have one repeatable workflow — following up on unpaid invoices, drafting quotes, writing product descriptions in your brand voice — you can package it as a Skill in about 25 minutes. Once installed, Claude loads those instructions automatically whenever the task comes up. Here is the full loop: plan, write, package, install, test.
What You’ll Need
- A claude.ai account (Pro, Max, Team, or Enterprise) or Claude Code on your computer.
- Code execution enabled on claude.ai (in Settings) — custom Skills on the web require it.
- One repeatable task you do at least weekly. The more boring and consistent, the better.
- Any plain-text editor: Notepad, TextEdit, VS Code.
Step 1: Pick One Repeatable Task
The most common beginner mistake is building a Skill that does everything. Don’t. Anthropic’s best practices say it plainly: keep it focused. One workflow, one Skill. Good first candidates: “draft polite payment-reminder emails for overdue invoices,” “turn rough meeting notes into a client-ready summary,” “write product descriptions in our brand voice.” If you can’t describe the task in one sentence, narrow it down. Skills compose — Claude can use several together automatically — so small, focused Skills beat one giant one.
Step 2: Create the Folder and Write the Frontmatter
Every Skill is a folder containing SKILL.md. Create one named with lowercase letters, numbers, and hyphens — e.g. invoice-follow-up — and put SKILL.md inside it. The file must start with YAML frontmatter holding two required fields:
--- name: invoice-follow-up description: Drafts polite payment-reminder emails for overdue invoices in our company tone. Use when the user mentions overdue invoices, payment reminders, or chasing late payments. ---
Rules from Anthropic’s docs: name is max 64 characters, lowercase/numbers/hyphens only, no “anthropic” or “claude”, no XML tags. description is non-empty, max 1,024 characters, no XML tags — and must say both what the Skill does and when Claude should use it. This one line is what Claude reads at startup to decide whether to trigger your Skill, so make it specific.
Step 3: Write the Instruction Body
Below the frontmatter, write plain-Markdown instructions — the onboarding doc you’d hand a sharp new employee. A structure that works:
- Context — who the company is, who the audience is, what “good” looks like.
- Workflow — numbered steps, in order.
- Rules — hard constraints: tone, length, things to never do.
- Examples — one example input and output, so Claude sees what success looks like.
Sample body for the invoice Skill:
## Workflow 1. Ask which invoices are overdue and how many days late, unless already provided. 2. Draft one email per invoice: subject, greeting, invoice number, amount, due date. Keep each under 120 words. ## Rules - Tone: friendly but firm. Never threatening. - Always use the customer's first name. Never invent an invoice number or amount. ## Example output Subject: Quick nudge: invoice #1042 (due Oct 10) Hi Maria, a friendly reminder that invoice #1042 for $850 was due Oct 10...
Start simple: basic Markdown first, scripts and code only later — if ever.
Step 4 (Optional): Add a Reference File
If the Skill needs background material that only matters sometimes — a price list, a brand-voice guide — don’t cram it into SKILL.md. Save it as REFERENCE.md in the same folder and mention it in SKILL.md. Thanks to progressive disclosure, Claude only opens that file when needed, so extra files cost nothing until used. Skip this step for your first Skill if you don’t need it.
Step 5: Package It as a Zip
Beginners stumble here most: the folder must be inside the zip — the files must not sit at the zip’s root. Correct: invoice-follow-up.zip → invoice-follow-up/ → SKILL.md. Compress the folder itself (right-click it), and double-check by opening the zip before uploading.
Step 6: Upload and Activate
Three installation paths — they don’t sync, so install separately wherever you want the Skill:
- claude.ai (easiest): Settings → Features → upload your zip. Custom Skills here are per-user: each teammate uploads separately.
- Claude Code: unzip into
~/.claude/skills/(personal) or the project’s.claude/skills/(shared with the team). Discovered automatically, no upload step. - Claude API: upload via the Skills API (
/v1/skills). Workspace-wide, but sandboxed with no network access — needs a developer.
Safety note, worth repeating from Anthropic: install Skills only from sources you trust, and audit every file first. A Skill gives Claude new capabilities through instructions and code — treat it like installing software.
Step 7: Test, Read the Misses, Iterate
Try several realistic prompts that should trigger the Skill — including casual phrasings a teammate would type, like “chase up the late invoices.” If Claude fires it on the wrong tasks, your description is too broad; if it never fires, it’s too narrow or missing trigger phrases. Fix the description first — the cheapest change, solving most misses — then adjust the body. Test after each change; when it fires reliably several times in a row, hand it to the team.
Shortcut: Record a Skill Instead of Writing One
claude.ai also offers “record a skill”: record your screen while you do the task once (up to about 10 minutes), and Claude studies the recording and proposes a Skill for review. Saved Skills appear under Customize → Skills and work exactly like hand-written ones — the fastest on-ramp for non-technical owners.
Pro Tips
- Specific beats clever in descriptions. “Use when the user mentions overdue invoices” fires; “use for financial communications” misfires.
- Examples beat adjectives. One example output teaches tone faster than a paragraph describing it.
Frequently Asked Questions
Do I need to code to create a Claude Skill?
No. A basic Skill is a folder with a Markdown file — the same writing you’d do for an SOP. Scripts are optional extras for advanced users.
How much does it cost?
Skills are free to create. On claude.ai you need a paid plan (Pro, Max, Team, or Enterprise) with code execution enabled; in Claude Code, custom Skills work with your existing subscription.
Will my Skill work everywhere I use Claude?
No — custom Skills don’t sync across surfaces. Install separately on claude.ai, Claude Code, or the API, wherever you want it.
Can my whole team use the Skill I built?
On claude.ai, Skills are per-user — each teammate uploads the zip. In Claude Code, share via the project’s .claude/skills/ folder. Via the API, uploaded Skills are workspace-wide.
Is it safe to install Skills made by others?
Only from sources you trust. Anthropic advises auditing every file, because a malicious Skill can direct Claude in ways its description doesn’t mention.
Conclusion
Your first Skill won’t be perfect, and it doesn’t need to be. Pick one boring, repeatable task, write a focused SKILL.md, zip it correctly, upload it, and iterate on the description until it fires reliably. That loop — describe, test, adjust — is the whole craft. Once you’ve done it once, turning your company SOPs into a library of Skills is just repetition. Start today.
