An open convention · v0.1

A tiny Markdown file that makes any AI shopping agent instantly know who you are.

Your sizes. Your style. What you already own and love. What to never recommend. Paste it into Claude, ChatGPT, or any agent that reads text — and skip the 15-question warmup every single time.

Your file. Your data. Your move.

Build mine View the spec on GitHub

homer.buyer.md

---
buyer_md_version: 0.1
updated: 2026-05-17
handle: Homer
region: Athens, GA
---

# About me

Serial founder, boater, Vizsla owner. Based in
Athens, GA, but most of what I buy gets used on
or near the water.

# Style

Mostly earthtone. Workwear-adjacent silhouettes
over preppy. Natural fibers when possible.

# Don't show me

- Fast fashion
- Anything from a cruise ship gift shop
- White pants

A trimmed example. See full ones →

Why this exists

Every time you ask an AI to help you shop, you spend the first ten messages explaining yourself. Your size. Your budget. The brands you like. The brands you've sworn off. The fact that you live somewhere humid and won't wear wool in July.

Then the conversation ends and that context dies with it. Next time, you start over.

buyer.md is one file you write once, paste anywhere, and never explain again.

It's not an app. It's not a service. It's not a startup. It's a convention — a small agreement about what a shopper-preferences file looks like so that any agent, on any platform, can read yours in seconds and act on it.

How to use it

1.

Write one.

Use the builder to draft yours through a short questionnaire, or hand-edit the template directly.
2.

Save it somewhere you can find it.

A note, a file, a Claude Project, a GitHub gist — whatever works.
3.

Paste it.

When you start a shopping conversation with an AI agent, paste your buyer.md at the top. Or upload it as a file. The agent reads it like any other context.
4.

Update it when you change.

New size, new taste, new boat? Edit the file. It's just Markdown.

What it looks like in practice

Without buyer.md

You: Find me a rain jacket.

Agent: Sure! Here are 10 options. What's your size? Budget? Style preference? Do you want waterproof or water-resistant? Are you using it for hiking, commuting, or fishing? Do you prefer hooded or hoodless?…

With buyer.md

You: Find me a rain jacket.

Agent: Based on your buyer.md — boater on the Georgia coast, size L, prefers natural fibers, owns a Grundens you like — here are three jackets worth looking at. The Helly Hansen is the closest match to what you already own; the Filson is a step up in materials at 2x the price; the Patagonia Torrentshell is the budget pick that still meets your sustainability lean. None have visible logos.

That's the whole game.

What goes in a buyer.md

Frontmatter — version, last-updated, handle, region, sizes, budget bands.
About me — a paragraph or two on who you are and how you use what you buy.
Sizes — across categories, with brand overrides where they matter.
Style — palette, themes, materials, fit, vibe. What you're drawn to.
Don't show me — anti-preferences. Often higher-signal than preferences.
Use contexts — boat, office, travel, gym. Each a short paragraph.
Things I own and love / didn't work — optional, very high-signal.
Notes to the agent — confirmation thresholds, autonomy, how to talk to you.

Every section is optional. The shortest useful buyer.md is about 20 lines. The longest is about 200.

What it's not

Not a wallet. No card numbers, no account numbers, no passwords. Ever.
Not a history database. It's a brief, not a ledger.
Not a contract with merchants. The file describes you to your agent. Your agent decides what (if anything) to share with sellers.
Not a standard yet. It's a convention. If it catches on, maybe it becomes one.

Privacy

A buyer.md is as private as you choose to keep it. If you paste it into a hosted AI, that AI sees it. If you put it in a public gist, the world sees it. Treat it like a personal note you'd hand to a personal shopper — useful to share with someone you trust, not something to leave on a bus.

Never put in a buyer.md:

· Payment info, account numbers, passwords, API keys
· Government ID numbers, full home address
· Anything you wouldn't paste into a chat window

This site never stores your file. The builder calls an LLM to draft your text and hands it back to you. Nothing is saved server-side. There are no accounts, no analytics, no third-party scripts.