What Are Skills? An Engineer's Guide to Teaching Claude Your Office Procedures
Every office has a fixed way of doing things: how a report looks, what you check in a calculation, how a quote is written. A skill lets you write that down once, so Claude follows your procedure every time without you explaining it again.
01What a skill is, in one sentence
A skill is a folder with an instruction file called SKILL.md. At the top of the file there is a name and a short description, followed by the instructions: what to do, in what order, and in what format.
You can add more files to the folder: a Word template, a logo, a checklist, a data table or a small script. Claude only uses them when the task calls for it.
Skills follow an open standard (Agent Skills, at agentskills.io). So the same folder can work in other tools that support the standard, not just in Claude.
02Picture a binder of procedures on the shelf
A new engineer does not memorize every office procedure. They glance at the binder spines on the shelf and pull out the right one only when they need it: "Daily site report procedure", "Calculation review checklist". Skills work exactly like that: Claude sees the titles of all the binders and opens only the one that fits the task.
03How Claude loads a skill, step by step
- 1Sees only titlesClaude knows the name and short description of every installed skill
- 2Spots a matchYou asked for a daily report? It sees the daily report skill fits
- 3Reads SKILL.mdOnly now does it load the full instructions
- 4Opens extra filesA template, logo or script is opened only if needed
- 5Follows the procedureThe output comes out in your format and order
04Skill, prompt or connector: what is the difference?
Prompt
A one-off instruction typed in the chat. Fine for a single question, but you have to write it again every time.
Skill
Fixed know-how and procedure: the "how to". Saved once, and Claude uses it on its own when it is relevant.
Connector
Access to an app or data: Gmail, Google Drive, a calendar. It gives Claude a key to the cabinet, not a recipe.
Plugin
A package that bundles several skills with connectors and commands, for example a complete kit for one line of work.
05What is ready-made, and what you need to start
Built-in Anthropic skills
Create and edit Word, Excel, PowerPoint and PDF files. Claude uses them automatically when you ask for a file.
Custom skills
Skills you create or upload yourself, based on your own office procedures.
Requirement: code execution
Skills need the "Code execution and file creation" option to be turned on in settings.
Where it works
On the Claude website and apps, in Claude Code, in Cowork and through the API. Availability depends on your plan and organization settings.
06Example: a company report with logo and fixed structure
07Example: checking a calculation note against our checklist
08What a simple SKILL.md looks like (plain lines)
- 1
name: daily-site-report
A short name in lowercase letters with hyphens.
- 2
description: Produces a daily report from a site engineer's notes
One sentence explaining when to use the skill. This is what Claude reads to decide whether to pull it.
- 3
Instructions: 1. Sort the notes into sections: weather, manpower, work, deviations, open issues
Simple lines in plain language, like a procedure written for a new employee.
- 4
2. Write each deviation with location, description and who is responsible
Precise instructions give consistent results.
- 5
3. At the end add a task table for tomorrow and use the file template.docx
A reference to another file in the same folder.
09Recommendations: which skill fits which use
| Common use | Recommended skill | Why |
|---|---|---|
| Creating Word, Excel, PowerPoint, PDF files | Built-in (from Anthropic) | Already there, works automatically when you ask for a file |
| Office report with logo and fixed structure | Custom: "office report" | Every report looks the same, no re-explaining |
| Reviewing a calculation note | Custom: "calculation review" + checklist | No item gets forgotten, results in a clear table |
| Quotes and offers | Custom: "quote format" | Line items, payment terms and exclusions always in the same order |
| Daily site report | Custom: "daily report" | Turns messy notes into a tidy report in a minute |
| Brand language and design | Custom: "brand style" | Consistent colors, fonts and tone in every document |
| Coordination meeting minutes | Custom: "meeting minutes" | Decisions, owners and due dates in a fixed format |
10How to create a skill in 5 minutes
- 1
Make sure code execution is on
In Claude's settings, under Capabilities, turn on "Code execution and file creation". In an organization, an admin may need to allow it.
- 2
Give Claude a good example
Upload a report you like and write: "Create a skill that produces reports in exactly this format".
- 3
Review what it made
Read the instructions. Fix anything inaccurate and add what only you know (for example "always state the standard number").
- 4
Save and enable it
Save the skill, or upload it as a ZIP file under Customize, then Skills. That is also where you turn each skill on or off.
- 5
Test it on a real task
Ask for a normal task and check the result. Not right? Adjust the instructions and try again.
11Do and don't
Do
- Install skills only from sources you trust
- Keep instructions short and focused, one skill per task
- Write a clear description that says when to use it
- Test on a few real cases before sharing with the team
Don't
- Install an unknown skill from the internet without reading it: it can contain scripts
- Put passwords or sensitive data inside a skill
- Write a "book" dozens of pages long in a single file
- Trust the output without your own engineering check
12FAQ
Do I need to know how to code to create a skill?
No. SKILL.md is a text file with instructions in plain language. The easiest way is to ask Claude to create one from your example, then fix it.
Which plans include skills?
According to the Claude Help Center, skills are currently available on the Free plan and on paid plans (Pro, Max, Team, Enterprise), as long as code execution is turned on. In organizations, the admin decides what is allowed.
If I install many skills, will Claude get confused?
Usually not. At first Claude only sees each skill's name and description, and opens the full content only when needed. That is why the description should be clear and not overlap with another skill.
Do skills only work in Claude?
Skills are built on the open Agent Skills standard, and other tools have adopted it, for example OpenAI's Codex. Still, check each tool on its own.
What is the difference between a skill and a connector?
A skill teaches Claude how to do something (a recipe). A connector gives it access to where the information lives, like Gmail or Google Drive. You often use both together.
Can a skill be harmful?
A skill can include scripts and instructions, so one from an untrusted source could leak data or take unwanted actions. Install only from known sources and read the files before enabling them.