Private beta · waitlist open
Save what strikes you. Say why. Your agents follow it.
craftrules captures the web pages whose design you love, keeps the reason behind each detail, and turns your reasons into rules that Claude Code, Cursor and Codex read before they design.
One email when a place opens. No newsletter.
Why it struck you
- 1DoThe price comes before the plan name: you compare numbers first.
- 2DoOne serif, for headings only. The interface stays sans.
- 3AvoidThree equal cards with icons say nothing about the product.
Measured on the live page
- Headings
- Serif 600 · 56/60
- Body text
- Sans 400 · 17/28
- Colours
- #FAF7F0#1F1E1B#D9502B
- Body contrast
- 14.8 : 1
References die where you save them
A bookmark, a screenshot, a link in a chat. Months later nobody remembers what was good about it, and your coding agent never saw it.
- 01
A screenshot without its reason
Was it the layout, the button or the type? The moment that made you save it is gone.
- 02
An agent without your taste
Ask for a landing page and you get the average of the web, the same gradient and the same three cards.
- 03
A rule nobody can check
"Make it feel premium" cannot be verified. A measured font size and a note on a real page can.
How it works
- 1
Save a page
Paste a link. craftrules captures it on desktop and phone and measures the fonts, colours, contrast and corner radii it really uses. Every capture keeps its date, so you see how a design changes.
- 2
Mark why
Draw a box around each detail that strikes you and write one line, something to do or something to avoid. A page holds as many reasons as you have.
- 3
Turn reasons into rules
Group your marks into rules such as "show the price before the plan name". Each rule cites its evidence, and nothing becomes a rule until you approve it.
Every claim says where it comes from
Three kinds of knowledge, never mixed, so you and your agents know what to trust.
Measured
Read from the live page, with the date, the address and the method. Never guessed.
Body 17/28 px · contrast 14.8 : 1
Your taste
A judgement with its author and date, drawn on the exact region it is about.
Do · the price before the plan name
Documented
A cited source, such as a usability study or a design guideline.
Source · a study on pricing tables
Your agents read it before they design
craftrules is an MCP server. Connect it once and your coding agent searches your library, reads the approved rules with their evidence and looks at the regions you marked, instead of guessing.
Works with any MCP client, such as Claude Code, Cursor and Codex. There is a JSON API too.
Design the pricing page of my app
craftrules · search_library("pricing")
Rule · your taste · approved
Show the price before the plan name.
Evidence: 4 marked regions on 3 sites, measured
Applying 3 rules from your library…
Questions
What is craftrules?
craftrules is a private library of design references for people who build products with AI coding agents. You save web pages that strike you, mark the reason on each detail, and turn those reasons into rules your agents read through MCP.
How is it different from Mobbin, Pinterest or a moodboard?
Galleries show screens other people picked. craftrules keeps your own picks with the reason for each detail, measures the live page instead of keeping only a picture, keeps every capture with its date, and hands the result to your agents as explicit rules.
Which coding agents does it work with?
Any client that speaks the Model Context Protocol (MCP), such as Claude Code, Cursor and Codex. There is also a plain JSON API with personal tokens.
What does "measured" mean?
When you save a page, a browser opens it and reads what it really uses, font families, sizes and weights, text and background colours, contrast and corner radii. Each value keeps its date, its address and the method that read it.
Are my references private?
Yes. Your library is private and nothing you save is published. Agents reach it only with a personal token that you create and can revoke at any time.
How much will it cost, and when does it open?
There is no price yet. People on the waitlist hear it first, before anything is charged. The library is in private use today, and the list tells us who to open it to next.
Hear when a place opens
Leave your email and we write once, when craftrules opens to new people. No newsletter, and you can ask to be removed at any time.