MCP WASM
A proof-of-concept implementation of a Model Context Protocol (MCP) server that runs in WebAssembly (WASM) within a web browser. This project demonstrates the integration of MCP tools and resources in a browser environment.
What is MCP WASM?
MCP WASM is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to proof-of-concept implementation of a model context protocol (mcp) server that runs in webassembly (wasm) within a web browser. this project demonstrates the integration of mcp tools and resources in a...
A proof-of-concept implementation of a Model Context Protocol (MCP) server that runs in WebAssembly (WASM) within a web browser. This project demonstrates the integration of MCP tools and resources in a browser environment.
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- A proof-of-concept implementation of a Model Context Protoco
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx mcp-wasmConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use MCP WASM
MCP WASM is a proof-of-concept TypeScript project that demonstrates running a full Model Context Protocol server inside WebAssembly within a web browser. It implements a calculator tool for arithmetic operations and an in-browser key-value storage resource, showing that MCP tool registration and resource templates can work entirely in a browser WASM context without any external server process or backend infrastructure.
Prerequisites
- A modern web browser with WebAssembly support (Chrome 90+, Firefox 89+, Safari 15+)
- Node.js 18 or higher for building the project
- npm for dependency management
- Basic familiarity with the MCP protocol and WebAssembly concepts
Clone the mcp-wasm repository
Clone the beekmarks/mcp-wasm repository from GitHub to get the full source code for this browser-embedded MCP server.
git clone https://github.com/beekmarks/mcp-wasm.git
cd mcp-wasmInstall project dependencies
Install all npm dependencies required to build and run the project, including the MCP SDK and WebAssembly build tooling.
npm installBuild the WebAssembly bundle
Compile the TypeScript server implementation into a WASM-compatible bundle that will run inside the browser.
npm run buildStart the development server
Launch the local HTTP development server that serves both the WASM bundle and the browser-based interface for interacting with the MCP tools.
npm run devOpen the browser interface and test tools
Open your browser to the local server address shown in terminal output. Use the calculator UI to perform arithmetic and the storage UI to set and retrieve key-value pairs within the current browser session.
MCP WASM Examples
Client configuration
As a browser-embedded server this project is primarily accessed via its web UI, but if connecting from a supported MCP client use the following configuration pattern.
{
"mcpServers": {
"mcp-wasm": {
"command": "npx",
"args": ["mcp-wasm"],
"env": {}
}
}
}Prompts to try
Example interactions with the WASM-hosted MCP calculator tool and key-value storage resource.
- "Calculate 256 divided by 16 using the calculator tool"
- "What is 99 plus 1?"
- "Store 'blue' under the key 'theme' in the browser storage"
- "Retrieve the value stored at key 'theme'"
- "Multiply 12 by 12 and tell me the result"Troubleshooting MCP WASM
WASM fails to initialize with a TypeError in the browser console
WebAssembly requires the page to be served over HTTP, not opened as a local file. Always use npm run dev to serve via the development server rather than opening index.html directly in the browser.
Build command fails with compilation errors
Ensure Node.js 18 or higher is installed (node --version) and run npm install before npm run build. If TypeScript errors persist, check that the tsconfig.json targets a WebAssembly-compatible module format.
Storage values do not persist after page refresh
This is by design — the storage is in-memory for the duration of the browser session. The project is a proof-of-concept; production use would require integrating IndexedDB or localStorage for durable persistence.
Frequently Asked Questions about MCP WASM
What is MCP WASM?
MCP WASM is a Model Context Protocol (MCP) server that proof-of-concept implementation of a model context protocol (mcp) server that runs in webassembly (wasm) within a web browser. this project demonstrates the integration of mcp tools and resources in a browser environment. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install MCP WASM?
Follow the installation instructions on the MCP WASM GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with MCP WASM?
MCP WASM works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is MCP WASM free to use?
Yes, MCP WASM is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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