Markdown

MD file (.md)

In one sentenceA simple way to format plain text with symbols: # for headings, ** for bold, - for bullets. It is the native language of AI.

What it means

Markdown files end in .md and are plain text, so any app can open them, but the symbols turn into formatting when displayed: # Heading, **bold**, *italic*, - bullet, [link](url).

AI models read and write Markdown fluently. It is why ChatGPT and Claude answers have headings and bullets, why AI agents keep their instructions in files like README.md, CLAUDE.md or AGENTS.md, and why note apps like Obsidian and the llms.txt standard use it.

How to use it

• Give AI your documents as Markdown when you can. It is cleaner than PDF or Word and uses fewer tokens.
• Keep a Markdown "context file" about your business that you can paste into any AI or drop into any project.
• Pasting AI output into LinkedIn? LinkedIn does not render Markdown, so the ** symbols show up. Convert it first.

Related terms

Obsidian llms.txt PDF Context Engineering