Every morning used to start the same way. Open Jira. Scan email. Dig through yesterday’s meeting notes for anything I missed. Copy tasks into my journal. Check which newsletters came in overnight. Piece together what my day actually looks like.

Over an hour. Every single morning. And the kicker? I was doing the exact same sequence every day — just explaining it to AI from scratch each time.

So I built a custom AI skill called “Prep My Day.” Wrote the instructions once, and now Claude handles all ten steps in about five minutes. Journal set up, tasks synced, newsletters summarized, meeting action items pulled in. The whole routine, done before I’ve had my coffee.

A custom AI skill is just that: you teach AI how to do something once, and it runs the same way every time. No more re-explaining yourself every morning because your brain hasn’t booted up yet.

Let me show you how to build your first one.

What is a custom AI skill?

Easiest way to think about it: a recipe card for AI.

When you cook from memory, you wing it. Sometimes it’s perfect; sometimes you forget the garlic. But when you write the recipe down — ingredients, steps, plating — you get the same dish every time.

A custom AI skill works the same way. It’s a saved set of instructions that tells AI what to do, what inputs it needs, and what the output should look like. Write it once. Run it whenever you want.

This is different from a normal prompt. A prompt is a one-off request — “Summarize my meeting notes.” You’ll get a summary, sure. But it’ll look different every time. Different format, different detail, different structure.

A skill is the whole workflow:

Take my meeting notes. Extract action items with owners and deadlines. Flag decisions that were made. List open questions. Format everything as a checklist I can paste into my project management tool.

Same structured output every time, no matter which meeting you feed it.

How to pick the right task

Not every task should be a skill. The best candidates are tasks you do regularly (weekly at minimum), that follow roughly the same steps each time, and where you want consistent output — not a creative surprise.

If you’re not sure where to start, these are the kinds of tasks that work well:

Summarize meeting notes into action items. You sit in meetings, you need action items afterward, and the format never changes.
Turn raw notes into a polished document. Messy bullets in, clean draft out.
Write a weekly status report. Same bones, different updates.
Draft a project brief from a client intake form. The client changes; the transformation doesn’t.
Prep your day. Pull tasks, updates, and priorities into one view each morning.
Respond to common customer questions with the same tone and depth every time.
Generate a content brief from a keyword — same research process, same output format, different topic.

If a task checks those boxes, it’s a good candidate.

Step 1: Map out your task

Before you write anything, document what you actually do when you perform the task by hand. Most people skip this. It’s the most important part.

Here’s how I mapped my morning routine before building Prep My Day:

Open yesterday’s journal entry
Copy it into a new file for today
Delete the completed tasks
Check Jira for new or updated tickets
Add new tasks to my journal
Scan newsletters for anything worth reading
Review recent notes and clippings
Check for action items from yesterday’s meetings

Then I broke it down one level further:

Inputs: Yesterday’s journal, my Jira board, newsletter inbox, meeting notes
Steps: Copy, clean, sync, scan, compile
Output: One journal entry for today with every task, update, and action item in one place

That’s your blueprint. Write down your inputs, your steps, your expected output. Be specific — “check email” isn’t a step. “Scan inbox for flagged messages and extract action items” is.

Step 2: Write your skill instructions

Now turn that blueprint into something AI can follow. You’re writing a file called SKILL.md — plain text with step-by-step directions. No code. No special syntax. Just clear instructions.

Here’s a simplified version of my Prep My Day skill:

# Prep My Day

You prepare the user's daily journal entry. This is a quick, automated task.

## Step 1: Find the most recent journal entry
1. Look for all files in the daily journal folder.
2. Find the most recent entry by date.
3. Read that file.

## Step 2: Create today's entry
1. Copy the contents of the most recent entry.
2. Remove all completed tasks.
3. Keep all incomplete tasks.
4. Reset the habits checklist (uncheck everything).
5. Clear the reflections section.
6. Save as today's date.

## Step 3: Sync tasks
1. Pull current tasks from the project management tool.
2. Add any new tasks that aren't already in the journal.

## Step 4: Summary
Tell the user their day is prepped. Show:
- How many tasks carried forward
- How many completed tasks removed
- How many new tasks synced

Plain language, no jargon. Numbered steps so AI knows the order. And a specific output section so you know exactly what you’ll get back.

Here’s the thing — you don’t even have to write this yourself. Take the blueprint you made in Step 1 and paste it into Claude with something like “My goal is to turn this into a SKILL.md file with step-by-step instructions.” It’ll give you a solid first draft. Then you just read through it, adjust anything that doesn’t match how you actually do the task, and move on to testing.

Your first skill doesn’t need to be ten steps. Start with the core workflow. You’ll add detail later once you see where AI needs more guidance.

Step 3: Test and refine

Run your skill three times with different inputs. Each time, watch for missing steps (did AI skip something you do by hand?), wrong formatting (is the output structured the way you need it?), or vagueness where you need specifics.

When I first ran Prep My Day, it had a subtle problem. Completed parent tasks were getting deleted — great. But their incomplete sub-tasks vanished with them. My “follow up with client” task just disappeared because it was nested under a completed parent.

The fix was one line: “When removing a completed task that has incomplete sub-tasks beneath it, keep those sub-tasks and promote them one level.”

That’s how skills get better. You don’t try to predict every edge case upfront. You run the skill, watch what happens, and tighten the instructions. Most fixes are a sentence or two.

After three runs, your skill should produce consistent output. If it doesn’t, the answer is almost always clearer instructions, not more complicated ones.

Step 4: Save your skill in Claude

Once your skill works, save it so you can use it anytime. Claude supports custom skills in both the desktop app (Cowork) and the web version at claude.ai. The format is the same for both.

First, package the skill:

Create a folder named after your skill (e.g., prep-my-day)
Put your SKILL.md file inside it
Zip the folder

Then upload it:

Open Settings > Customize > Skills
Click the ”+” button, then “Create skill”
Select “Upload a skill”
Upload your ZIP file

Your skill shows up in your list, and Claude uses it automatically whenever you ask it to do that task. You can toggle it on or off whenever you want.

Anthropic has a full walkthrough here: Use Skills in Claude.

Three skills you can build today

You don’t need to start with something as involved as my morning routine. Here are three skills you can have running in 30 minutes or less.

Weekly report summarizer

Takes your raw weekly notes and turns them into a clean status report.

# Weekly Report

Take the user's raw notes and create a weekly status report with these sections:

1. Key accomplishments (bullet points, past tense)
2. In progress (what's actively being worked on)
3. Blockers (anything stalled and why)
4. Next week's priorities (top 3)

Keep each bullet to one sentence. Use plain language, no jargon.

Customer email responder

Drafts a response to customer emails in your company’s voice.

# Customer Email Response

Read the customer's email and draft a response that:

1. Acknowledges their specific question or issue
2. Provides a clear, direct answer
3. Includes next steps if applicable
4. Closes with an offer to help further

Tone: friendly and professional. Use "we" not "I."
Keep the response under 150 words.

Content brief generator

Takes a keyword and produces a structured brief for a blog post.

# Content Brief

Given a topic keyword, create a content brief with:

1. Recommended title (under 60 characters)
2. Target audience (one sentence)
3. Search intent (what the reader wants to learn)
4. Recommended outline (5-8 sections with one-sentence descriptions)
5. Key points to cover (bullet list)
6. Suggested word count

Focus on what would help the reader, not what would impress search engines.

FAQ

Do I need to know how to code? Not even a little. Skills are written in plain English. If you can write a checklist, you can write a skill.

How detailed should my skill be? As detailed as the task requires. Prep My Day is long because the routine has a lot of steps. A simple email responder might be ten lines. Start short, add detail wherever you find gaps.

Can I share skills with my team? Yes. On Claude’s Team and Enterprise plans, you can share skills with specific people or your whole organization. Updates distribute automatically, so everyone stays on the same version.

What if my skill doesn’t work right the first time? Expected. Run it a few times, spot what’s off, and add a line or two of more specific instructions. Skills get sharper every time you use them.

How to Build a Custom AI Skill for Your Business