Markdown

A few weeks ago my wife asked me for something and I sent her back a Markdown file. Pure muscle memory. Same energy as hitting Ctrl+Z in iMessage and expecting it to undo what I typed. Later that day: "I know you're a coder, but what the f*** is this?"

Fair question. So here's the answer.

It's formatting you type instead of click. In a normal document, you highlight a word and hit the little B button to make it bold. Markdown skips the button. You just wrap the word in symbols and the formatting happens. It stays plain text the whole time, then renders clean when something displays it.

You only need three symbols to read 90% of it:

• # at the start of a line makes a heading. (More hashes, smaller heading. # is the big title, ### is a small one.)
• ** wrapped around a word makes it bold.
• - at the start of a line makes a bullet in a list.

That's the whole starter kit. Here's what it looks like written out versus how it shows up:

# My Grocery List

Stuff I **actually** need:

- eggs
- coffee
- the good butter

Type that anywhere that speaks Markdown and you get a real heading, a bolded word, and a tidy bulleted list. No buttons touched.

You've already been reading it for months. Those AI replies that come back with neat headers, bolded key phrases, and clean lists? That's Markdown. The model isn't reaching for a formatting toolbar. It's typing these symbols, and your app is quietly turning them into the nice layout you see.

Here's the part that actually matters, though: Markdown is the native language of AI.

Think about it like this. AI reads everything as tokens, little bricks of text (and every brick costs money and room). A Word doc or a PDF is a brick wall with a bunch of invisible junk mortared in: fonts, layout codes, page settings, the works. The AI has to chew through all of that before it can even get to your actual words. Markdown is just the words, with a few plain symbols marking what's important. Nothing wasted.

So it's the cheapest, cleanest way to hand information to an agent, and it's what they hand back. Ask one to write you a file and you'll almost always get Markdown. (Oddly, Claude desktop sometimes spits out a .docx instead. Still no idea why.)

One genuinely useful tip that'll save you money and grief:

Don't feed AI a raw PDF if you can avoid it.

PDFs burn a pile of tokens just getting decoded into something the model can read. Convert it to Markdown first (you can literally ask the AI to do it) and all that effort goes into the part you actually care about, the thinking, instead of the unpacking.

Learn three symbols, #, **, and -, and you're basically fluent in the language every agent you'll ever touch already speaks.