FAQ
Questions, answered
Can't find it here? Email hello@whichbutton.xyz. Pricing questions live on the pricing page.
What is whichbutton?
A markup layer for your running site that your AI coding agent can read. Paste a URL (localhost works), circle what could be better, and type a note. Your agent connects to whichbutton over MCP, pulls the open notes with annotated screenshots, changes the code, and checks each one off.
Why not just describe the change to the agent?
Because "the button under the hero is too close to the cards" is a guess for the agent. It has to work out which button, which page, which breakpoint. A circle on a screenshot, plus the page and viewport it was drawn on, removes most of that guessing.
Which agents does it work with?
Anything that speaks MCP over HTTP. The settings page has setup for Claude Code, Cursor, and Codex. You create an API key, add the server, then tell the agent "fix the whichbutton feedback". For agents without MCP, Copy for agent puts the note and a screenshot on your clipboard to paste in.
What does the agent actually get?
For each open item: your comment, the page, the view, and where the mark sits. On public pages it also gets the element under your mark (tag, classes, text, selector) and a screenshot with the mark drawn on it. After it fixes something, the agent calls resolve_feedback with a note on what it changed, and you see that note on the item in whichbutton. If a note is unclear, the agent can ask you a question there instead of guessing.
Does it work on localhost?
You can mark up local URLs. They load directly in the review, so your dev server with hot reload works the way it normally does. Our servers can't reach your machine, so your agent gets local notes as text: your comment, the page, the view, and where the mark sits, without a screenshot or element details.
Can I review mobile and tablet layouts?
Yes. Switch between desktop, tablet, and mobile. Notes stay with the width you left them on, and the agent is told which one, so it can tell a phone note from a desktop one.
How do I get started?
Create an account, pick Monthly or Lifetime, and start a project from a URL or a design image. Then make an API key in settings and add the MCP server to your agent. The whole setup takes a few minutes.
Who can see my projects?
Only you. There are no public review links or shared pages. Your agent reads your notes with an API key you create and can revoke at any time.