Artifact WorkbenchStop describing the change.
Just make it.
Artifact Workbench is a macOS app for fixing an HTML page by hand. Open a file or a folder — whatever your browser opens straight from disk — click any element and adjust it: size, colour, spacing, wording. It writes back to the file in your project. No upload, no download, no copy to reconcile.
The last 10% is faster to do than to describe
A page lands on your disk nearly right — written by an AI, exported from a tool, saved from somewhere, built by React. The hero is too big, the button is the wrong blue, one line of copy is off. Describing each of those to an agent is a sentence to write, thirty seconds to five minutes of waiting, and a fresh file to read through. Several times a session.
Click, then adjust
Pick an element in the preview. Size, weight, colour, alignment, padding, radius, position — typed exactly or nudged a pixel at a time.
Drag with snapping
Move an element and it catches on the edges and centres around it, then holds there while your hand wobbles. Guides show what it lined up with.
The agent, when you need it
Structure, logic, text a script generates — the things clicking cannot reach. It runs the Claude CLI you already have, after taking a snapshot it can revert.
It edits the file you already have
Open it where it lives — one HTML file, or a folder with its CSS, scripts, images and fonts beside it — and saving writes to that file. Nothing is uploaded, nothing is downloaded, and there is no second copy to reconcile with your repository. Your next agent run picks up from what you just changed.
Works on plain HTML and on React that renders in the browser — even when every element was built by a script and has no line in the file. An edit lands as a CSS override, so it survives a re-render and needs no build step and no source map.
Free
| Price | Free. No account, no key, no limit on saves. |
| Requires | macOS 11 or later, Apple silicon. |
| Network | Editing and saving work offline. The one request it makes is looking for a new version. |
Questions
Do I need an API key or an account?
No. Direct editing is the whole product and it needs neither. The optional agent uses the Claude CLI already installed on your machine.
What does it change in my file?
Style edits become one CSS block at the end of <head>, marked so it can be found and undone. Text edits replace the wording in place, and only when it appears exactly once — otherwise it says so rather than guessing.
Can I undo?
Edits are held until you save, so nothing touches the file until you ask. ⌘Z takes back the last one. Agent runs snapshot first and can be reverted whole.
How is this different from MarkViewer?
MarkViewer reads and writes Markdown. Artifact Workbench opens HTML pages — a file or a folder, from anywhere — and lets you change them by hand. Same author, different job; both free.