# justdraw.fyi

> A vector editor in the browser that an AI agent can actually drive. Every drawing is a URL. There is no account and nothing to install. The editor, the command line, and an AI agent all send the same JSON commands, so an agent's edit is a real edit — undoable, autosaved, and visible live to whoever is watching the tab.

## What makes it different

- **An agent draws objects, not pixels.** It places a rectangle with a centre, a radius, a fill — an object you can afterwards select, move, recolour and delete. It does not generate an image of a drawing.
- **One protocol, four seats.** The keyboard, the toolbar, the `jd` CLI and an AI agent all emit the same command (`element.draw`, `group.create`, `arrange.align`, …). There is exactly one implementation of what each command means, so the machine interface cannot drift from the product.
- **The browser is the engine.** The server relays; the open tab does the geometry. Drawing commands therefore need the project open in a browser, and reading commands do not.
- **Every project teaches itself.** `GET /p/<uuid>.md` returns a briefing generated from the live project: what is currently drawn, the whole command surface, and `curl` examples with that project's id already substituted in.
- **No login.** The UUID is the capability: whoever holds the link can edit that drawing, and nobody else can find it.

## How an agent uses it

1. Create a project: `POST https://app.justdraw.fyi/api/v1/projects` → `{"uuid": "...", "url": "/p/..."}`
2. Read the briefing: `GET https://app.justdraw.fyi/p/<uuid>.md`
3. Send commands: `POST https://app.justdraw.fyi/api/v1/agent` with `{"cmd": "element.draw", "project": "<uuid>", "args": {...}}`

The `Origin` header is required on every POST or the request is rejected with 403. Drawing commands return 409 unless the project is open in a browser.

## Docs

- [Tool: Outline View](https://www.justdraw.fyi/posts/tool-outline-view/): When the fills are lying to you about what the geometry is really doing.
- [Tool: The Parametric Shapes](https://www.justdraw.fyi/posts/tool-the-parametric-shapes/): Star, polygon, spiral, grid, flare — and why a triangle is not a polygon with three sides.
- [Tool: Layers and Groups](https://www.justdraw.fyi/posts/tool-layers-and-groups/): A group should move like one thing. An AI agent taught me we had got this wrong.
- [Tool: Artboards](https://www.justdraw.fyi/posts/tool-artboards/): A page is a printing constraint. An artboard is a page you chose.
- [Tool: The Two Erasers](https://www.justdraw.fyi/posts/tool-the-two-erasers/): One erases shapes. One erases paths. They look identical and they are not.
- [Tool: Knife and Scissors](https://www.justdraw.fyi/posts/tool-knife-and-scissors/): Two ways to cut. One splits at a point; the other slices through everything in its path.
- [Tool: Width](https://www.justdraw.fyi/posts/tool-width/): A line of constant thickness is a machine's idea of a line.
- [Tool: Reshape](https://www.justdraw.fyi/posts/tool-reshape/): A curve that is wrong in the middle is not a curve that is wrong at a point.
- [Tool: Curvature and Smooth](https://www.justdraw.fyi/posts/tool-curvature-and-smooth/): Say where the curve should pass. Let the handles work themselves out.
- [Tool: The Pen](https://www.justdraw.fyi/posts/tool-the-pen/): The hardest tool in the toolbar, and the one that makes it a vector editor at all.
- [Tool: Shape Builder](https://www.justdraw.fyi/posts/tool-shape-builder/): Drawing an outline requires you to know the answer before you start. Carving lets you find it.
- [Introducing the Agent API](https://www.justdraw.fyi/posts/introducing-the-agent-api/): Paste a project link at an AI and it can draw. Not generate a picture — draw.
- [Introducing jd, the Command Line](https://www.justdraw.fyi/posts/introducing-the-command-line/): A vector editor you can pipe into. Every command prints the id of the thing it made.
- [Introducing the Editor](https://www.justdraw.fyi/posts/introducing-the-editor/): What does a tool with no account cost you in capability? Nothing, and here is the tool.
- [Introducing justdraw.fyi](https://www.justdraw.fyi/posts/introducing-justdraw-fyi/): How much ceremony should it take to draw a box and an arrow?
- [Hello, world](https://www.justdraw.fyi/posts/hello-world/): The very first post on justdraw.fyi.

## Full text

- [llms-full.txt](https://www.justdraw.fyi/llms-full.txt): every post above, inlined, for answering from a single fetch.