# MCPixels

> A 1024×1024 pixel-art canvas that a person and an AI agent edit together, live, in the
> same browser tab. The editor hands an agent six WebMCP site tools — registered by the
> page itself via `document.modelContext.registerTool` — so the agent is a participant
> rather than a pixel pipe. No backend, no account, no API keys.

Coordinates are centred: x and y run -512..511, y downward. The tools are `draw_pixel_art`
(the only one you send pixel data to), `read_canvas`, `selection`, `edit`, `view` and
`export_pixel_art`. Pixel data travels as rows of one-character palette entries, not as
per-pixel coordinates — a 32×32 sprite costs about 400 tokens that way instead of 22,500.
Rows can also be run-length encoded (`format: "rle"`), which puts a 200×200 scene in one
call at about 1,500 characters and lets a read of that size come back exact.

There is nothing to call over HTTP: the tools only exist inside a loaded page, in a
browser that supports WebMCP (the ChatGPT desktop app's browser, or Chrome 149+ with
`chrome://flags/#enable-webmcp-testing`).

## Docs

- [Homepage as markdown](https://mcpixels.app/index.md): what the site is, in prose.
- [Skill: drawing on MCPixels](https://mcpixels.app/.well-known/agent-skills/drawing-on-mcpixels/SKILL.md): the wire format, the ops string, mirroring, reading before redrawing, and working alongside the person.
- [auth.md](https://mcpixels.app/auth.md): there is no authentication; here is why.

## Machine-readable discovery

- [MCP server card](https://mcpixels.app/.well-known/mcp/server-card.json): SEP-1649 card for the in-page WebMCP server.
- [API catalog](https://mcpixels.app/.well-known/api-catalog): RFC 9727 linkset.
- [ARD capability manifest](https://mcpixels.app/.well-known/ai-catalog.json): agentic resource discovery entries.
- [Agent skills index](https://mcpixels.app/.well-known/agent-skills/index.json): skills with SHA-256 digests.

## Source

- [github.com/filip-papic-bs/MCPixels](https://github.com/filip-papic-bs/MCPixels): the whole editor, AGPL-3.0-or-later. Built for the [WebMCP Challenge](https://webmcp.devpost.com/).