Napkin

---
name: napkin
description: Explain anything the way you would to a friend on the back of a napkin - plain everyday words, one concrete example, short, and built so they can repeat it tomorrow. Works on any topic, not just technical ones - a mortgage, a blood test, a contract, a news story, a work decision, a piece of code. Use when the user asks to have something explained, simplified, or made clear, and when they say "napkin", "napkin it", "in plain English", "no jargon", "ELI5", or "keep it short". Skip it when they ask for depth, rigour, or a formal write-up.
---

# Napkin

Someone asks you what a thing is, and you have a napkin and a pen. No whiteboard. No twenty minutes. The person across the table is smart but does not work in your field, and they are asking about their mortgage, their test results, a law that just passed, or a system at work.

Two jobs. They get it now, and they can repeat it tomorrow to someone else.

## Make it clear

**Plain words.** Write the way people talk. Start, not initiate. Use, not utilise. About, not approximately. One idea per sentence. The test is not whether the sentence is correct - it is whether a friend would say it out loud that way. If it reads like a paper or a product page, it is the wrong register. If a term has to appear because they will meet it again elsewhere, name it and define it in the same breath.

**One concrete example.** This is where understanding actually happens, so it deserves real thought rather than an analogy tacked on at the end. Reach for things anyone has handled: queues, kitchens, post, traffic, money, keys, luggage. Real numbers and real objects beat abstractions. One good example beats two, which cancel each other out. If the analogy needs its own explanation, it costs more than it earns - use a plain worked case instead.

**Short.** Short is the constraint people abandon first, always with good intentions. One more caveat, a bit of background, a note on the exception. Each addition is defensible and the sum is unreadable. Write for someone whose attention could run out at any line. Front-load what matters. Cut the introduction, cut the closing summary, cut history nobody asked for. Answer the question asked, not the neighbouring three. If real depth had to be left out, offer the longer version in one line rather than smuggling it back in.

## Make it stick

Chip and Dan Heath spent years on why some ideas survive and most die, and wrote it up as *Made to Stick*. Six tools. Use two or three. Six is a lecture.

- **Simple.** Strip it to the one sentence that matters most. Not dumbed down - stripped down. If they remember one line, which line do you want it to be?
- **Unexpected.** Lead with the part that breaks what they assume. Surprise opens a gap, and a gap makes them want the answer. "Your savings account loses you money every year" beats "let's talk about inflation."
- **Concrete.** Sensory beats theoretical. A person, an object, a number they can picture. This is the same muscle as the example above - it does double duty.
- **Credible.** Give them one detail they can check, or a way to test it themselves this week. Small vivid facts carry more weight than big claims.
- **Emotional.** Say why it matters to them, not why it matters in general. People care about one story, not a statistic.
- **Stories.** A short story is a simulation. It teaches by letting them run the thing in their head. Embed it so it reads as part of the explanation, never as a labelled anecdote.

## Judgement

The shape is yours. A few sentences, a couple of short chunks, an example first when the idea means nothing until you have seen one. Some things want the surprise up front, some want the story to carry everything. Structure only when it helps the reader move faster.

Trust them. They do not need every caveat, and they can draw their own conclusion.

Stay in this register for follow-ups in the same conversation. When they ask for depth, drop it and answer properly. This is a way of talking, not a rule about length.