sketch/design — System Design Interview Board

Name: sketch/design — System Design Interview Board
Author: tGhattas

by tGhattasversion 0.1.2i★ –iRuns on your computer

Registry nameio.github.tGhattas/sysdesign-board

Install

Overview

Description from the maker (original English)

Hand-drawn whiteboard for system design mock interviews; your AI watches, asks and gives feedback.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Design, images & audio

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: SYSDESIGN_PORT

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "sysdesign-board": {
      "command": "npx",
      "args": [
        "-y",
        "sysdesign-board"
      ],
      "env": {
        "SYSDESIGN_PORT": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add sysdesign-board --env SYSDESIGN_PORT=your-value -- npx -y sysdesign-board

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "sysdesign-board": {
      "command": "npx",
      "args": [
        "-y",
        "sysdesign-board"
      ],
      "env": {
        "SYSDESIGN_PORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "sysdesign-board": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "sysdesign-board"
      ],
      "env": {
        "SYSDESIGN_PORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

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

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account tGhattas, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Design, images & audioi

More stars than 0% of the other 2192 servers in this category
Published to the registry more recently than 66% of the other 2192 servers in this category
Basic checks equal to or better than 100% of the other 2192 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is sketch/design — System Design Interview Board safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.2) reached the registry 16 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Figma Context MCP, Claude Real Video, Figma MCP Server

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Figma Context MCP

by GLips

Give your coding agent access to your Figma data. Implement designs in any framework in one-shot.

Runs on your computer★ 16,165MITUpdated 5 months ago

Install

Claude Real Video

by HUANGCHIHHUNGLeo

Let any LLM watch a video locally — and search everything it has ever watched.

Runs on your computer★ 2,284MITUpdated 2 months ago

Install

Figma MCP Server

by figma

Figma’s official server gives AI your design data so it can turn designs into code or describe them accurately. Connects to Figma’s cloud.

Runs in the cloud★ 2,152Updated 13 months ago

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

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.

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:// .trycloudflare.com/mcp?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- .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 --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

sketch/design — System Design Interview Board

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Design, images & audioi

Common questions

Alternatives

Figma Context MCP

Claude Real Video

Figma MCP Server

README from the maker

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