Table of Contents
What this lesson is about
This lesson introduces two ways to extend what Claude can do: plugins, which add new tools and capabilities, and skills, which give Claude detailed instructions for specific tasks you repeat regularly. Skills in particular require no coding at all — they are plain text files — making them the most accessible power feature in the entire Claude ecosystem for non-technical users.
Apps on your phone and recipe cards in a kitchen
Two analogies help here, because plugins and skills are genuinely different things.
Plugins are like apps on your phone. Your phone came with a set of built-in features — calls, messages, a camera. But you can visit the app store and install new apps that add capabilities your phone did not originally have. A ride-hailing app adds the ability to book transport. A banking app adds the ability to manage your accounts. Each app is a self-contained bundle that extends what your device can do.
Plugins work the same way for Claude. Claude arrives with a set of built-in capabilities. A plugin is an installable bundle that adds new ones — the ability to search the web, connect to a calendar, pull data from a project management system, or interact with a piece of software Claude could not reach before.
Skills are like detailed recipe cards given to a chef. Imagine you run a catering business and you have a head chef. The chef is talented and can cook many things. But you have a signature dish — a specific prawn curry made exactly the way your grandmother made it, with precise quantities, a specific sequence of steps, and particular finishing instructions. You do not teach the chef a new cooking technique. You hand them a detailed recipe card that tells them exactly how to make this one dish to your standard.
A skill is that recipe card. It is a text file — specifically a file named SKILL.md — that you place in your project folder. When Claude encounters it, it reads the instructions inside and follows them precisely for that task. No new tools, no new capabilities — just very specific, repeatable guidance for something you do regularly.
Plugins vs skills — a quick comparison
| Plugins | Skills | |
|---|---|---|
| What they add | New tools and capabilities | Detailed instructions for a specific task |
| Format | Installable bundle (like an app) | A markdown text file (SKILL.md) |
| Requires coding? | No — installed from a marketplace | No — written in plain English |
| Who writes them? | Developers publish them; you install | You write them yourself |
| Best for | Connecting Claude to external systems | Standardising how Claude handles a repeated task |
| Example | A Google Calendar plugin that lets Claude read your schedule | A skill that formats every meeting note in your house style |
| Lives in | Your Claude settings | Your project folder |
Plugins — adding new capabilities
How to find and install a plugin
The plugin marketplace is a directory of pre-built plugins that you can browse and install without any technical knowledge. Think of it as the app store for Claude.
To find and install a plugin:
- Open Claude — either claude.ai or your Claude desktop application
- Navigate to Settings (usually a gear icon or your profile menu)
- Select Plugins or Integrations from the settings menu
- Browse or search for the capability you need — for example, “calendar”, “Slack”, or “web search”
- Click Install on the plugin you want
- Follow any authorisation steps — some plugins need permission to access an external service on your behalf (for example, a Google Calendar plugin will ask you to sign in with your Google account)
- Once installed, the plugin’s tools are available in your Claude sessions automatically
When a plugin is active, Claude gains access to new tools — specific actions it can take using that plugin. A calendar plugin might give Claude a read_calendar tool and a create_event tool. You do not need to know the tool names; Claude knows what is available and will use the right tool when the task calls for it.
What plugins are best used for
Plugins are most valuable when you want Claude to interact with systems that live outside your computer — your calendar, your email, your project management tool, your CRM. Without a plugin, Claude can only work with what you paste into the conversation. With a plugin, Claude can go and fetch information, or take action, on your behalf.
Skills — giving Claude precise instructions for repeated tasks
What a SKILL.md file looks like
A SKILL.md file is a markdown text file — the same format as the lesson you are reading right now. It contains instructions written in plain English. When Claude reads it, it treats those instructions as the authoritative guide for how to handle a particular type of task.
Here is a simple, realistic example — a skill for summarising supplier emails:
# Skill: Summarise Supplier Email
## Purpose
Summarise incoming supplier emails for a commercial manager.
The summary must be brief, professional, and action-oriented.
## When to use this skill
Use this skill whenever the user pastes a supplier email and asks for a summary.
## Output format
Produce a summary using this exact structure:
**Supplier:** [Supplier name if stated]
**Subject:** [One sentence describing the topic]
**Key points:** [2–4 bullet points covering the main content]
**Action required:** [What the reader needs to do, if anything. If nothing, write "None."]
**Deadline:** [Any dates mentioned. If none, write "Not specified."]
## Tone
Professional. Plain English. No filler phrases.
Maximum 150 words total.
## Example output
**Supplier:** Packaging Solutions (Pty) Ltd
**Subject:** Price increase effective 1 July
**Key points:**
- 8% price increase across all corrugated carton lines
- Driven by paper pulp cost increases
- New pricing schedule attached
**Action required:** Review attached pricing schedule and confirm acceptance by 15 June.
**Deadline:** 15 June for confirmation; 1 July for price change effective date.
That is the entire file. No code. No technical syntax. Just clear, specific instructions that Claude will follow every time it encounters a task that matches this skill.
How to invoke a skill in a Claude session
To use a skill, you first need to place the SKILL.md file in the relevant project folder — the same folder that contains the files you are working on, or your Obsidian vault’s skills directory if you have one set up.
When Claude Code is running in that folder, it reads the skill files automatically. You can also invoke a skill explicitly by referencing it:
/skill summarise-supplier-email
Or simply describe the task and Claude will identify the matching skill:
Summarise this supplier email using the supplier email skill.
If you are using Cowork, skills in your project folder are discovered automatically — you do not need to invoke them manually.
Writing your own skill — a complete example
How to identify which tasks deserve a skill
The best skills are built around tasks you perform every week. The simplest way to find them is to look for anything you explain to Claude the same way more than twice. If you have pasted the same set of instructions into three different Claude conversations, that instruction set belongs in a skill file.
Common candidates for non-technical business owners:
- Formatting meeting notes into a consistent structure
- Summarising reports in your preferred style
- Reviewing documents against a standard checklist
- Writing emails in your house tone
- Preparing weekly status updates from a set of inputs
Once you have identified the task, write the skill the same way you would explain it to a new employee on their first day: what the task is, what good output looks like, what format to use, and any rules to follow.
A complete skill: formatting meeting notes
Here is a full SKILL.md file for formatting meeting notes. You could create this file right now, save it in your project folder, and start using it today.
# Skill: Format Meeting Notes
## Purpose
Take raw, unstructured meeting notes and reformat them into a clean,
professional record that can be shared with attendees and filed.
## When to use this skill
Use this skill when the user pastes rough meeting notes and asks for them
to be formatted, cleaned up, or turned into a proper record.
## Output format
Produce a formatted meeting record using this exact structure:
---
**Meeting:** [Title or topic of the meeting]
**Date:** [Date of the meeting — DD Month YYYY format]
**Attendees:** [List of names and roles, comma-separated]
**Facilitated by:** [Name of the meeting chair or organiser, if mentioned]
---
### Context
[One or two sentences describing the purpose of the meeting.]
### Decisions made
[Numbered list of decisions reached during the meeting.
If no decisions were made, write "No formal decisions recorded."]
### Action items
| # | Action | Owner | Due date |
|---|---|---|---|
| 1 | [Action description] | [Name] | [Date or "Not specified"] |
### Discussion notes
[A clean, third-person summary of the main discussion points.
Remove filler, repetition, and irrelevant tangents.
Keep it factual and professional. Maximum 200 words.]
### Next meeting
[Date and purpose of the next meeting, if mentioned.
If not mentioned, write "Not scheduled."]
---
## Tone and style rules
- Write in South African English (colour, organised, prioritise)
- Third person throughout — never "I" or "we"
- Past tense for what was discussed; future tense for action items
- No bullet points in the Discussion notes section — use prose
- Do not add information that was not in the original notes
- If something is unclear in the raw notes, mark it with [clarify] rather than guessing
## What to do if the raw notes are very sparse
If the notes contain less than three sentences, tell the user:
"These notes are too brief to format into a full record.
Please add: decisions made, action items and owners, and a brief summary of the discussion."
Save this file as SKILL.md inside a folder named meeting-notes (or add it to your skills library in your Obsidian vault). From that point forward, any time you paste rough notes into a Claude session in that folder, Claude will produce a perfectly formatted meeting record — every time, in the same structure, to the same standard.
How plugins and skills work together in Cowork mode
Cowork — Anthropic’s desktop tool for non-developers — is where plugins and skills combine most naturally. When you open a project in Cowork:
- Plugins that you have installed in your Claude settings are active and available — Claude can reach your calendar, your email, your project tools
- Skills in your project folder are discovered automatically — Claude reads them on startup and knows how to handle the tasks they describe
- You can invoke either without switching tools, opening settings, or typing long instruction sets — just describe what you want
A practical example of the two working together: you ask Claude in Cowork to “prepare a formatted meeting record for tomorrow’s budget review.” Claude uses the calendar plugin to fetch the meeting details, pulls in any relevant files from the project folder, then uses your meeting notes skill to format the output to your exact standard. Two capabilities, one natural language request.
| What happened | How it worked |
|---|---|
| Claude found tomorrow’s meeting | Calendar plugin — connected to your Google Calendar |
| Claude pulled the relevant files | Cowork’s file access — reading from your project folder |
| Claude formatted the output correctly | Meeting notes skill — instructions in your SKILL.md file |
This is the practical value of the Roof layer: individual components that each do one thing well, combining into workflows that feel seamless.
Practical Exercise
a. Think of one task you explain to Claude repeatedly — something you have typed similar instructions for more than twice. Write the task name at the top of a blank document, then write 4–6 sentences describing exactly what good output looks like: the format, the tone, the length, and any rules to follow. This is the raw material for your first skill.
b. Using the meeting notes skill in this lesson as a template, turn your description into a properly structured SKILL.md file. Include at minimum: a Purpose section, a When to use this skill section, an Output format section, and a Tone and style rules section. Save it as SKILL.md in a relevant folder on your computer.
c. Open a Claude Code session in that folder and paste in a real example of the task — rough material that the skill should process. Ask Claude: “Use the skill in this folder to handle this.” Review the output against your instructions. If something is not right, update the skill file and try again. Iteration is how skills improve — most good skills go through two or three refinements before they are reliable.
Common problems and how to fix them
Claude is not finding the skill file
Claude reads SKILL.md files from the folder it is currently working in. If Claude is not picking up your skill, check two things: first, that the file is actually named SKILL.md (capital letters, .md extension); second, that Claude Code is running in the correct folder. You can confirm the active folder by typing pwd in the terminal — pwd stands for print working directory, which shows you exactly where you are in your file system.
The skill is being found but Claude is not following it precisely
This is an instructions problem. Skills work best when they are specific and unambiguous. Read through your skill file and look for anything that could be interpreted in more than one way. Add examples — an “Example output” section in your skill is one of the most effective ways to anchor Claude’s behaviour. If Claude is still drifting, ask it: “Here is my skill file and here is what you produced — what part of the instructions led to this result, and how should I rewrite them to get this instead?”
A plugin is installed but Claude does not seem to be using it
Plugins need to be active in your current session. Check your settings to confirm the plugin is enabled and not just installed. Some plugins also require a specific trigger — for example, a calendar plugin might only activate when you explicitly mention your calendar. Check the plugin’s documentation in the marketplace for any activation requirements.
Two skills are conflicting with each other
If you have multiple skill files in the same folder covering overlapping tasks, Claude may blend them in unexpected ways. The fix is to keep each skill narrowly scoped — one task per file — and make the “When to use this skill” section as specific as possible. If you genuinely need two related skills, put them in separate subfolders and invoke them explicitly rather than relying on automatic discovery.
The plugin asks for permissions every time
Most plugins store their authorisation once you grant it. If yours is asking for permission repeatedly, it may be a session or browser cache issue. Try signing out and back in, or reinstalling the plugin. If the problem persists, check the plugin’s support page in the marketplace.
What you have learned in this lesson
- Plugins are installable bundles that add new tools and capabilities to Claude — like apps on a phone — and are best used to connect Claude to external systems like calendars, email, and project tools
- Skills are plain-text markdown files (
SKILL.md) that give Claude detailed, repeatable instructions for a specific task — like a recipe card handed to a chef - The key difference: plugins expand what Claude can do; skills define how Claude should do something you already ask for regularly
- Installing a plugin requires no technical knowledge — it is a browse, click, and authorise process from the marketplace
- Invoking a skill can be done explicitly with a command or implicitly by describing the task
- A
SKILL.mdfile is written in plain English using sections: Purpose, When to use, Output format, and Tone rules - The best skills are built around tasks you explain to Claude the same way more than twice — look for your most repeated instructions
- In Cowork mode, plugins and skills combine automatically — Claude can pull live data through a plugin and format it using your skill in a single request
- Skills require no coding whatsoever — they are the most accessible power feature for non-technical users in the entire Claude ecosystem