What is a Claude skill?

A Claude skill is a written set of instructions Claude follows so it does a task the way you want it done, every time. It has a name, a short description that tells Claude when to use it, and the steps. It is the same idea as an SOP with a different reader: an SOP is written for a person, and a skill is written for an AI.

Skills are a real feature, not a trend. Claude describes them as folders of instructions that it loads when a task calls for them, and the format follows an open standard so it is not locked to one tool. Read how Claude explains skills →

Want the full picture, with 10 real examples? Read what Claude skills are and how they differ from MCP and Projects →

The catch is that most SOPs are missing things an AI needs and a person just knows: what triggers the job, what done looks like, and which judgement calls matter. This tool finds those gaps and asks about them before it writes the skill.

From SOP to skill: a real example

This is a real run of the tool. The SOP on the left is the kind most businesses have: five short steps that only make sense to the person who does them. The tool asked two questions first, what “make sure the numbers look right” actually means and whether each invoice needs approval before it is sent. The skill on the right is what came back.

SOP: Send the monthly client invoice

1. On the last working day of the month, open Xero and go to Sales, then Invoices.
2. Check the timesheet for each active client and add the hours to a new draft invoice.
3. Make sure the numbers look right.
4. Email the invoice to the client's accounts contact using the invoice email template.
5. Mark it as sent in the client tracker spreadsheet.

---
name: monthly-client-invoice
description: Draft, check and send the monthly client invoices in Xero from timesheet hours, then log them in the client tracker. Use on the last working day of the month, or when I say "run the monthly invoices".
---
# Send the monthly client invoice

## When to use this
On the last working day of the month, for every active client.

## What you need first
- Access to Xero (Sales > Invoices)
- The timesheet for the month, with all hours entered and finalised [FILL THIS IN: where does the timesheet live?]
- The client tracker spreadsheet
- The invoice email template
- Each client's agreed rate and accounts contact email

## Steps
1. Open Xero and go to Sales, then Invoices.
2. List every active client to be invoiced this month.
3. Open the timesheet and pull the hours for each client for this billing period.
4. Create a new draft invoice in Xero for each client and enter the hours.
5. Check each draft against these three things:
   - Hours on the invoice match the hours on the timesheet
   - The rate applied matches the client's agreed rate
   - Nothing has been carried over or doubled up from last month
6. Present the finished drafts to me for approval. Show client name, hours, rate and total for each one. Wait for my go-ahead.
7. Send each approved invoice to the client's accounts contact using the invoice email template.
8. Mark each invoice as sent in the client tracker spreadsheet.
9. Tell me which invoices went out and flag any that were held back.

## How to check it worked
- Every active client has an invoice in Xero marked as sent
- Each invoice total matches the timesheet hours at the agreed rate
- The client tracker shows every invoice marked as sent for this month
- No client has been invoiced twice for the same period

## Notes
- Never send an invoice without my approval first.
- If a client's hours look unusually high or low compared to last month, flag it rather than sending.
- If the timesheet is incomplete or the agreed rate is missing for a client, stop and ask me before drafting.
- Skip any client who is inactive or on hold this month.

Notice what it added: a clear trigger, the three checks spelled out, an approval step before anything is sent, and a flag where it needed something from the owner, marked [FILL THIS IN] instead of guessed.

What makes a good skill

Whatever tool you use, a skill that works has the same five things. This tool checks for each one and asks when something is missing.

1. A clear trigger. What starts the job: a day, an event, a request. A person just knows. An AI has to be told.
2. Direct steps. Each step starts with an action. “Send the invoice”, not “Invoice sending”.
3. Edge cases. What to do when something is missing or looks wrong: stop and ask, skip it, or flag it.
4. Approval points. Anything that sends, publishes, deletes or spends money has a clear rule: wait for your go-ahead, or run on its own.
5. A way to check it worked. What should exist at the end, so you can tell the skill did its job.

Claude also needs a short description, 200 characters at most, that says what the skill does and when to use it, because that is how it decides whether to use the skill. The tool writes that for you. Then test it: run it on something real and tell Claude what it got wrong.

How to use your skill

1. Copy the skill block the tool gives you.
2. Save it in a plain text file called SKILL.md, inside a folder with the same name as your skill.
3. Zip the folder.
4. In Claude, go to Customize, then Skills. Click the plus, choose Create skill, then Upload a skill, and pick your zip file. Switch the skill on.
5. Run it once on something real, then tell Claude what it got wrong so you can tighten the skill.

Not using Claude? Paste the skill into any AI chat and say, “Follow these instructions whenever I ask for this.”

A skill is only as good as the SOP behind it

Questions, answered