Whimsical

Whimsical MCP Server

The official Whimsical MCP server. Ask Claude, ChatGPT, Cursor or any MCP client for a flowchart, mind map, sequence diagram, wireframe or architecture diagram, and it builds an editable Whimsical board in your workspace. You get a real file your team can open, edit and comment on, not a static image. The server can also search, read, edit and comment on the boards and docs you already have.

• Endpoint: https://mcp.whimsical.com/mcp (hosted by Whimsical, Streamable HTTP, nothing to install)
• Authentication: OAuth 2.1 with PKCE. There's no API key to manage.
• Plan: every tool works on the free plan, which includes up to 50 board objects a month. Paid plans have no object limit.
• Clients: Claude, Claude Code, ChatGPT, Cursor, VS Code with GitHub Copilot, Grok, Codex, and any client that supports remote MCP servers.

Quick start

In Claude Code:

claude mcp add --transport http whimsical https://mcp.whimsical.com/mcp

In other clients that support remote MCP servers, add a server with this URL and sign in to Whimsical when prompted:

https://mcp.whimsical.com/mcp

Then try: *"Create a flowchart in Whimsical of our user signup flow."* Setup steps for each client are below.

What you can build

Each example below is a prompt you can try. The agent creates the file in your Whimsical workspace and replies with a link. Clients that support it also show a preview in the chat.

Flowcharts

Create a flowchart in Whimsical of a user login: login page, validate credentials, go to the dashboard if they're valid, show an error and retry if they're not.

You get an auto-laid-out flowchart with decision nodes, labeled connectors and a clean top-to-bottom layout. Ask for left-to-right and the agent re-runs the layout.

Sequence diagrams

Make a sequence diagram in Whimsical of the OAuth authorization code flow between the browser, our web app, the authorization server and our API.

The agent creates a sequence diagram with one lifeline per actor and the messages between them in order.

Architecture diagrams

Create a technical diagram in Whimsical of our system: a React frontend calls an API gateway, which routes to auth, billing and notification services, each with its own database.

The agent lays out the components on a board with service boundaries and connectors showing how requests and data move between them.

Mind maps

Create a mind map in Whimsical to brainstorm features for a mobile app, with branches for onboarding, core features, monetization and growth.

You get a mind map with the central topic and its branches, laid out horizontally. Ask for a vertical layout to get a top-down tree.

Wireframes

Create a wireframe in Whimsical for a settings page with sidebar navigation, a profile section with an avatar and form fields, and a danger zone at the bottom.

The agent builds the screen from wireframe elements (containers, inputs, buttons, icons) with a flexbox layout, so follow-ups like "make the primary button full width" keep everything aligned.

Sticky notes

Create sticky notes in Whimsical for a retro on our last sprint, grouped into what went well, what didn't, and ideas to try next.

You get sticky notes on a board, grouped into the clusters you asked for and laid out automatically, ready for your team to add to and vote on.

Docs and tables

Write up the technical spec for the new API as a Whimsical doc, with a table comparing the three options we discussed.

Docs support headings, lists, links, code blocks and tables. Tables can also go on a board.

Work with what's already in your workspace

Search my Whimsical workspace for anything about "API design" and summarize what you find.

Add a rate limiting step to the API flow diagram, then leave a comment asking the team to review it.

The agent can search your workspace, read boards and docs (including a PNG snapshot of a board), edit existing diagrams, move files between folders, and read, write and resolve comment threads.

Tools

See the tool reference for details and more example prompts.

Setup

Claude

Whimsical is a verified connector in Claude's connector directory. Open the Whimsical connector, click Connect and sign in to Whimsical.

Claude Code

claude mcp add --transport http whimsical https://mcp.whimsical.com/mcp

Run /mcp in Claude Code to sign in.

ChatGPT

Use the Whimsical app for ChatGPT:

1. In ChatGPT, open Settings → Plugins.
2. Search for Whimsical, or use the link above.
3. Click Connect and complete the authorization.

Then type @Whimsical in any chat. See the ChatGPT guide for more.

Cursor

Or install the Whimsical plugin from Cursor's plugin directory, or add it by hand: open Cursor → Settings → Cursor Settings → Tools & MCP, add a new MCP server, and save this configuration:

{

"mcpServers": { "whimsical": { "url": "https://mcp.whimsical.com/mcp" } } }

See Cursor's MCP documentation for more.

VS Code (GitHub Copilot)

1. Press ⌘ Shift P (or Ctrl Shift P) and run MCP: Add Server.
2. Select HTTP.
3. Paste https://mcp.whimsical.com/mcp and press Enter.
4. When prompted for a server ID, enter whimsical.
5. Choose whether to add the server globally or only for the current workspace.

Grok

1. Go to grok.com/connectors.
2. Click New Connector, then select Custom.
3. Enter https://mcp.whimsical.com/mcp and sign in to Whimsical.

See the Grok guide for more.

Other clients

Any client that supports remote MCP servers over Streamable HTTP can connect with this configuration:

{

"mcpServers": { "whimsical": { "url": "https://mcp.whimsical.com/mcp" } } }

Authentication

The server uses OAuth 2.1 with PKCE. The first time you connect, your client opens a browser window where you sign in to Whimsical and approve access to your workspace. The agent then works in Whimsical as you, using the access you approved.

Remote and desktop MCP

This repository covers the remote MCP server, which Whimsical hosts and recommends for most people. Whimsical also offers a desktop MCP server that runs inside the Whimsical desktop app and works on the file you have open. To set it up, contact support.

FAQ

Is this the official Whimsical MCP server? Yes. Whimsical builds, hosts and maintains it, and it's listed in the official MCP Registry as com.whimsical/mcp. Community-built Whimsical MCP servers also exist; this is the one maintained by Whimsical.

Do I need to install or run anything? No. The server runs at https://mcp.whimsical.com/mcp. You add the URL to your client and sign in.

Do I need an API key? No. Sign-in uses OAuth, so there are no keys to create, store or rotate.

Does it make images or editable diagrams? Editable diagrams. Everything the agent creates is a normal Whimsical file in your workspace that you and your team can open, change and comment on. The fetch tool can also return a PNG snapshot of a board.

Can it read and update diagrams I already have? Yes. It can search your workspace, read boards and docs, edit them, re-run the layout and work with comments.

Troubleshooting

• Sign-in doesn't open or fails. Run /mcp in Claude Code, or use your client's reconnect action, to sign in again. The browser redirects back to your client once you've signed in to Whimsical.
• Tools don't appear after install. Run /reload-plugins in Claude Code, or restart your editor in other clients.
• `401` or "Missing Bearer token". Your session has expired. Sign in again via /mcp or your client's reconnect action.
• No Whimsical account. Create one for free at https://whimsical.com. The server signs you in to your existing workspace.

Links

• Overview: https://whimsical.com/mcp
• Setup guide: https://whimsical.com/learn/integrations/mcp
• Tool reference: https://whimsical.com/learn/ai/mcp-tools
• Support: help@whimsical.com
• Privacy policy: https://whimsical.com/terms/privacy