Every pro Claude user splits each task into three parts using the 10-80-10 rule.

The first 10 percent is yours. The idea, the context, the examples, and what done looks like. The things only you can supply.

The middle 80 percent is Claude's. Drafting, organizing, calculating, building, all of it, while you stay out of the way.

The last 10 percent is yours again, and it is two jobs. Job one is fixing the output in front of you. Job two is deciding where that fix should live so you never make it again.

In this post, I will teach you this simple workflow that creates a compounding return of better outputs with fewer edits needed.

Not using the rule has costs

The opposite of the rule has a shape too. Zero setup, a one-line prompt, and whatever comes back gets published or forwarded unread. Call it 0-100-0.

Researchers spent the last year measuring what it costs.

Two hours per instance. A BetterUp Labs and Stanford study in Harvard Business Review found 40 percent of desk workers in the United States received low-effort AI “workslop” in the past month, and each piece took its recipient nearly two hours to untangle. The same study put the bill at 9 million dollars a year for a 10,000-person company.

The sender pays too. In that study, 42 percent of workslop recipients said they now trust the sender or publisher less.

Nobody is checking. A University of Melbourne and KPMG survey of more than 48,000 workers across 47 countries found 66 percent of employees who use AI have relied on its output without evaluating it.

Notice what those studies all say. Not a single one of them describes a failure of the AI. Every one is due to the user failing to be part of the front 10% and/or the back 10%.

Part One: Your First 10 Percent

A Brief, Not a Prompt

A prompt asks for a thing. A brief hands over a job. Five parts, and you can type all five in about ninety seconds.

1. The job in one sentence. Name the deliverable and name the reader in the same breath.

Write a 400-word email to a customer who asked for a refund in month two.

2. The raw material. Paste the thread, the transcript, last quarter’s version, the actual numbers. You can attach up to 20 files to a single chat, at up to 500MB each, so there is no reason to make Claude guess at facts sitting on your desktop.

3. The standard. Show one example of good instead of describing good. Paste something you liked and say what you liked about it.

Describing your standard is slow and inexact. “Professional but approachable” could mean forty different things. One pasted example settles it in a single paste, and it carries the details you would never think to write down.

4. The shape. Word count, number of sections, format, and how it ends.

Three sections, 600 words total, no headings, ends with one question.

If you leave the shape open, Claude picks one, and it tends to pick long and heavily formatted.

5. The don’ts. The two or three things you fixed last time.

Do not open with a summary. Do not use headings.

The Same Job, Briefed Two Ways

Here is a real task. A bookkeeping firm sends a monthly note to restaurant owners about their numbers, and the person in charge asks Claude to create it.

❌ The 0-percent version.

Write our monthly client email about their numbers.

What comes back is competent but useless AI slop.

✅ The 10-percent version.

Write the monthly numbers email to one client, Maria, who owns two taco shops and reads this on her phone between shifts. She has no finance background.

Her numbers are attached. Last month’s email is pasted below, and I want the same voice, especially the way it explains the food cost line in plain words.

350 words, four short paragraphs, no headings, plain text for email. Ends with one specific question about a decision she has to make.

Do not open with a summary. Never say headwinds or challenges, say it went up or down and say why. If you need a number I did not give you, write [NEED INPUT] instead of estimating.

Same job. The second one took ninety seconds longer to write and it comes back close enough to send.

The Other Half of the First 10: Where You Start the Job

Before you type a word, you must make a decision most people never notice they are making. Where on Claude does this chat need to happen?

The three choices of where to start your chat.

A plain new chat. Right for one-off work and for anything you are unlikely to repeat. Everything Claude needs has to come from your brief, because nothing else is feeding it.

A chat inside a project. Right for work that belongs to something ongoing. The project already carries the facts and the standing rules, so today’s brief only has to carry today’s material. This is where your brief gets to be two lines and an attachment.

A chat that starts with a skill. If a skill exists for the job, then hit the forward slash ( / ) to make sure it fires with your first message brief.

Starting in the wrong place is the most common invisible mistake in this entire post, because nothing warns you.

Expert Tips

Make Claude write the brief with you. When you are not sure you covered everything, add one line and send.

Before you start, ask me the questions you need answered to do this well, and then create a professional brief that explains what I want you to create.

One extra round trip, and it catches the gap you did not know you had. This is the single easiest upgrade in the post, and it works on any task big enough to matter.

Raise the effort when the job is hard. Click the model name next to the send button and choose an effort level. The options run Low, Medium, High, Extra high, and Max, though which ones you see depends on the model you are using, and one of them is marked as the default. Raise it to Max for anything with a lot of moving parts, or where being wrong is expensive.

Name the destination, not just the format. “This is going in a Substack post” or “this goes in a plain text email” prevents a whole category of correction, because it tells Claude which formatting will survive where you are pasting it.

Give it permission to push back. Add one line to briefs where you are not certain your own plan is right.

If you think the approach I described is wrong, say so before you start.

Part Two: Your Last 10 Percent

This is where the compounding lives, and it has two halves.

The second part of this post is for paid subscribers only. Upgrade now so that you can implement the 10-80-10 rule on your Claude before the end of the day.

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