How do I install Sketch/design — System Design Interview Board?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does Sketch/design — System Design Interview Board need an API key?

The publisher lists these environment variables: SYSDESIGN_PORT.

What transport does Sketch/design — System Design Interview Board use?

Sketch/design — System Design Interview Board runs locally over stdio.

When was Sketch/design — System Design Interview Board last checked?

Last checked 2026-11-10. Hand-drawn whiteboard for system design mock interviews; your AI watches, asks and gives feedback.

Sketch/design — System Design Interview Boar MCP server

Power your agent

Add this server

The publisher's own command. Not a PlugMCP endpoint.

Add to Cursor Add to VS Code Run on PlugMCP

Host a copy with our keys and logs.

Local command

npx -y [email protected]

Credentials from the publisher

SYSDESIGN_PORT — Local port for the whiteboard page (http://localhost:<port>). Defaults to 4321.

Claude Code has no install link for a local command. Copy the command below and run it in a terminal.

shClaude Code

1SYSDESIGN_PORT=<value> claude mcp add io.github.tghattas-sysdesign-board -- npx -y sysdesign-board@0.1.2

Run in a terminal.

jsonClaude Desktop

1{2  "mcpServers": {3    "io.github.tghattas-sysdesign-board": {4      "command": "npx",5      "args": [6        "-y",7        "[email protected]"8      ],9      "env": {10        "SYSDESIGN_PORT": "<value>"11      }12    }13  }14}

claude_desktop_config.json

Local · npmPublisher installStep-by-step: add this in Claude

Remote URL or a command on your machine? How the two installs differ

Run on PlugMCP

Host a copy with our keys and logs.

A new server you create. It is not this listing's official endpoint. Use the publisher install when you want their URL and their credentials.

Launch

Server facts

Local

Transport: stdio
Version: 0.1.2
API key

Tools

No tool list yet. Remote servers get one after the first health check.

FAQ

Questions

sketch/design — the system design interview board

A hand-drawn whiteboard for system design mock interviews, plus an MCP server that turns Claude or ChatGPT into your interviewer. It sees your board, listens to you, talks back, pins questions on your components, and ends with scored feedback.

A mock interview in progress: a URL shortener diagram, an interviewer question pinned on Redis, and the voice/text chat

Pencil-style canvas: a paper or chalkboard theme, with shapes that look drawn by hand (rough.js + perfect-freehand)
27 system design components: load balancer, API gateway, CDN, cache, SQL and NoSQL databases, object store, queue, Kafka-style stream, pub/sub, workers, serverless functions, auth, monitoring, ML and more
Arrows that stay attached to components, with labels, curved or elbow routes, and dashed lines for async flows. Hover a component and drag its blue dot to connect it.
Interview panel: the problem, a timer, a phase tracker, chat, voice in (speech-to-text) and voice out (the interviewer's replies are read aloud)
The interviewer can read your diagram as structured data, look at a picture of it, pin comments on components, highlight things, sketch reference designs, and grade you at the end
Runs entirely on your machine. The AI runs in your own Claude or ChatGPT app, on your existing subscription, with no API keys.

Install

Requires Node.js 18+.

Your AI app	How to connect	Billed to
Claude Desktop	Double-click `sysdesign-board-x.y.z.mcpb` from Releases, or run `npx -y sysdesign-board install`	Claude Pro / Max
Claude Code	`claude mcp add sysdesign-board -- npx -y sysdesign-board`	Claude Pro / Max
Codex CLI	Add it to `~/.codex/config.toml` (below)	ChatGPT Plus / Pro
ChatGPT (desktop / web)	Developer Mode connector through a tunnel (below)	ChatGPT Plus / Pro
Cursor, Windsurf, VS Code, others	The standard MCP JSON (below)	Your plan there

The .mcpb one-click file is Claude Desktop only. Every other app runs the same npm package.

Claude Desktop

Option A: one-click. Download the .mcpb file from Releases and double-click it. Claude Desktop shows an install dialog.

Option B: command line. First quit Claude Desktop completely (macOS: ⌘Q; Windows: tray icon → Quit). Claude rewrites its config file from memory when it quits, which would drop the new entry. Then run:

npx -y sysdesign-board install

Reopen Claude Desktop.

Option C: edit the config yourself (again, with Claude Desktop quit). The file is at:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux (unofficial builds): ~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "sysdesign-board": { "command": "npx", "args": ["-y", "sysdesign-board"] }
  }
}

On Windows, use "command": "cmd", "args": ["/c", "npx", "-y", "sysdesign-board"]. If Claude can't find npx (common with nvm, Volta or asdf), use the absolute path from which npx (macOS/Linux) or where npx (Windows).

Claude Code

Either add the server directly:

claude mcp add sysdesign-board -- npx -y sysdesign-board

Or install the plugin, which also adds an interview skill, from this repo's marketplace. Run these inside Claude Code:

/plugin marketplace add tGhattas/sysdesign-board
/plugin install sysdesign-board@sysdesign-board

Codex CLI

Add this to ~/.codex/config.toml (Windows: %USERPROFILE%\.codex\config.toml):

[mcp_servers.sysdesign-board]
command = "npx"
args = ["-y", "sysdesign-board"]
tool_timeout_sec = 120

ChatGPT app

ChatGPT connects to MCP servers over public HTTPS, so you run the board locally and expose only its /mcp endpoint through a tunnel. The board itself, its API and its WebSocket refuse any request that doesn't come from localhost.

Start the board, and keep this running:
```
npx -y sysdesign-board serve
```
In another terminal, open a tunnel (here with cloudflared):
```
cloudflared tunnel --url http://localhost:4321
```
Get your private connector token:
```
npx -y sysdesign-board token
```
In ChatGPT, go to Settings → Apps & Connectors → Advanced, enable Developer Mode, then Create a connector with the URL https://<your-tunnel>.trycloudflare.com/mcp?token=<token> and no authentication.

Treat that URL like a password. To change the token, delete ~/.sysdesign-board/token, or set SYSDESIGN_TOKEN yourself.

Any other MCP client

{ "command": "npx", "args": ["-y", "sysdesign-board"] }

Use it

Start a new chat and say:

Start a system design interview with me on my sketch board.

Or use the interview prompt from your app's prompt or slash menu. The board opens at http://localhost:4321.

Draw your design. Talk with the 🎤 mic (your message is sent when you pause) or type in the panel.
The interviewer keeps listening between replies. It is woken by what you say, and when you stop drawing for a few seconds.
Click I'm done when you're finished to get a feedback card with scores.

The board also works without any AI: run npx -y sysdesign-board serve and open http://localhost:4321.

Tools the interviewer gets

Tool	What it does
`start_interview`	Sets the problem, level and duration, opens the board, and speaks the opening line
`wait_for_candidate`	Waits for your speech or messages, or for board changes once you stop drawing
`say`	Sends a chat message, read aloud
`get_board`	Structured diagram: components, connections (with labels; dashed means async), zones, notes, and what changed
`get_board_image`	A PNG of the whole board (for handwriting and sketches)
`annotate` / `clear_annotations`	Pin or remove "INTERVIEWER" comment bubbles on components
`highlight`	Makes components glow, optionally zooming to them
`draw_on_board`	Adds components, connections, notes and zones in the same sketchy style
`set_phase`	Requirements → Estimation → API & Data → High-level → Deep dive → Wrap-up
`end_interview`	Feedback card with 1–5 scores, strengths and improvements
`get_transcript`, `open_board`	Housekeeping

Voice

Speech-to-text uses the browser's Web Speech API. Use Chrome, Edge or Safari; Firefox doesn't support it.
Text-to-speech uses your system voices. Toggle it with "Voice replies" in the panel. The mic pauses while the interviewer speaks, so it doesn't transcribe itself.
The native voice modes inside the ChatGPT and Claude apps can't be piped into another page. Those voice models are only available through paid APIs.

Keyboard

V select · H hand / hold Space · R rect · D diamond · O ellipse · A arrow · L line · P pen · T text · N sticky note · F zone · E eraser · K laser · C components · I interview panel · Q tool lock · G grid snap · ⌘/Ctrl Z undo · ⌘/Ctrl D duplicate · ⇧1 fit · ? all shortcuts

Privacy Policy

The full policy is in PRIVACY.md. In short:

What it handles: your board, the interview chat and voice transcripts, your settings, and a local access token.
Where it's stored: only on your machine, in the browser's local storage for the board page and in ~/.sysdesign-board/. The author runs no server, and there are no accounts, analytics or telemetry.
What leaves your computer:
- When the AI interviewer calls a tool, the AI app you connected receives the board description, a picture of the board, your messages and your transcripts, under that provider's privacy policy.
- The mic uses your browser's speech recognition. Chrome sends the audio to Google; Safari uses Apple's speech service.
- npx downloads the package from npm.
- With the optional tunnel, /mcp requests pass through the tunnel provider.
Security:
- The board, its API and its WebSocket only answer localhost requests from localhost pages. Other websites and tunnels are refused, which also blocks DNS-rebinding attacks.
- The HTTP endpoint (/mcp) always requires the token.
Sharing and retention: nothing is sold or shared. Data stays until you clear the board or delete ~/.sysdesign-board/.
Contact: open an issue.

Troubleshooting

The server doesn't appear in Claude Desktop. Claude was probably running when the config was edited and saved over it. Quit it fully, run npx -y sysdesign-board install, then reopen.
"npx: command not found" in Claude's logs. Use an absolute path to npx (see Option C), or run npx -y sysdesign-board install, which writes absolute paths for you.
Port 4321 is taken. Set SYSDESIGN_PORT (or --port=5000). In the .mcpb extension it's a setting.
The mic does nothing. Open the board in Chrome, Edge or Safari and allow microphone access.
Several apps connected at once? That's fine. The first one hosts the board and the others share it.

CLI

sysdesign-board            MCP server over stdio (what AI apps launch)
sysdesign-board serve      Board + HTTP MCP endpoint only
sysdesign-board install    Add to Claude Desktop (quit it first)  [--npx | --local]
sysdesign-board token      Print the HTTP MCP token / URL

Development

git clone <this repo> && cd sysdesign-board
npm install
npm run dev

npm run dev starts the hub on :4321 with reload, and Vite on :5173. Other scripts:

Command	What it does
`npm run build`	Builds the board UI and bundles the server into one file
`npm run build:mcpb`	Packs `build/sysdesign-board-<version>.mcpb`
`npm run typecheck`	Type-checks the web and server code
`node scripts/mcp-smoke.mjs`	Drives every MCP tool against a running board
`npm run lock:plugin`	Refreshes the Claude plugin's `package-lock.json` (run after the new version is on npm)

Releasing a new version:

Run npm version <x.y.z> --no-git-tag-version. This also updates server.json and the plugin's version and pinned dependency.
Run npm publish.
Run npm run lock:plugin. The lockfile needs the published package's checksum, so this comes after publishing.
Commit, then tag and push.
Make a GitHub release with npm run build:mcpb.
Run mcp-publisher publish for the MCP Registry.

The code lives in three folders:

web/: the board (React UI plus the canvas engine in web/src/engine.ts; renderer and component glyphs in web/src/render/)
server/: the hub (HTTP, WebSocket and persistence), the MCP tools and the CLI
shared/: the data model, component catalog and geometry

License

MIT

Add this server

Host a copy with our keys and logs.

Server facts

Tools

Questions

How do I install Sketch/design — System Design Interview Board?

Does Sketch/design — System Design Interview Board need an API key?

What transport does Sketch/design — System Design Interview Board use?

When was Sketch/design — System Design Interview Board last checked?

Documentation

sketch/design — the system design interview board

Install

Claude Desktop

Claude Code

Codex CLI

ChatGPT app

Any other MCP client

Use it

Tools the interviewer gets

Voice

Keyboard

Privacy Policy

Troubleshooting

CLI

Development

License