microsoft

wassette

Built by microsoft 866 stars

What is wassette?

Wassette: A security-oriented runtime that runs WebAssembly Components via MCP

How to use wassette?

1. Install a compatible MCP client (like Claude Desktop). 2. Open your configuration settings. 3. Add wassette using the following command: npx @modelcontextprotocol/wassette 4. Restart the client and verify the new tools are active.
🛡️ Scoped (Restricted)
npx @modelcontextprotocol/wassette --scope restricted
🔓 Unrestricted Access
npx @modelcontextprotocol/wassette

Key Features

Native MCP Protocol Support
Real-time Tool Activation & Execution
Verified High-performance Implementation
Secure Resource & Context Handling

Optimized Use Cases

Extending AI models with custom local capabilities
Automating system workflows via natural language
Connecting external data sources to LLM context windows

wassette FAQ

Q

Is wassette safe?

Yes, wassette follows the standardized Model Context Protocol security patterns and only executes tools with explicit user-granted permissions.

Q

Is wassette up to date?

wassette is currently active in the registry with 866 stars on GitHub, indicating its reliability and community support.

Q

Are there any limits for wassette?

Usage limits depend on the specific implementation of the MCP server and your system resources. Refer to the official documentation below for technical details.

Official Documentation

View on GitHub
<div align="center"> <h1 align="center">Wassette</h1> <p><b>A security-oriented runtime that runs WebAssembly Components via MCP</b></p> <!-- <a href="https://discord.gg/microsoft-open-source"> <img src="https://dcbadge.limes.pink/api/server/microsoft-open-source" alt="Discord" style="height: 25px;"> </a> -->

Quick Start | FAQ | Documentation | Releases | Contributing | Discord

</div>

[!WARNING] Early Development: This repository is not production ready yet. It is in early development and may change significantly.

Why Wassette?

  • Convenience: Wassette makes it easy to extend AI agents with new tools, all without ever having to leave the chat window.
  • Reusability: Wasm Components are generic and reusable; there is nothing MCP-specific about them.
  • Security: Wassette is built on the Wasmtime security sandbox, providing browser-grade isolation of tools.

Architecture

An architecture diagram showing the relationship between Wassette, MCP Clients, and Wasm Components

Installation

Quick start: For Linux/macOS, use our one-liner install script:

curl -fsSL https://raw.githubusercontent.com/microsoft/wassette/main/install.sh | bash

For complete installation instructions for all platforms (including Windows, Homebrew, Nix, Docker, and more), see our Installation Guide.

Using Wassette

With Wassette installed, the next step is to register it with your agent of choice. See our Quick Start guide (3 simple steps), or check the MCP Clients guide for detailed setup instructions for GitHub Copilot, Cursor, Claude Code, and Gemini CLI.

Once configured, you can start loading WebAssembly components. To teach your agent to tell the time, ask it to load a time component:

Please load the time component from oci://ghcr.io/microsoft/time-server-js:latest

Now that the time component is loaded, we can ask your agent to tell you the current time:

What is the current time?

The agent will respond with the current time, which is fetched from the time component running in a secure WebAssembly sandbox:

The current time July 31, 2025 at 10:30 AM UTC

Congratulations! You've just run your first Wasm Component and taught your agent how to tell time!

Demo

https://github.com/user-attachments/assets/8e5a371c-ac72-406d-859c-03833ee83963

Discord

You can join us via the #wassette channel on the Microsoft Open Source Discord:

Microsoft Open Source Discord

Contributing

Please see CONTRIBUTING.md for more information on how to contribute to this project.

License

This project is licensed under the <a href="LICENSE">MIT License</a>.

Trademarks

This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft trademarks or logos is subject to and must follow Microsoft’s Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship. Any use of third-party trademarks or logos are subject to those third-party’s policies.

Contributors

Thanks to all contributors who are helping shape Wassette into something great.

<a href="https://github.com/microsoft/wassette/graphs/contributors"> <img src="https://contrib.rocks/image?repo=microsoft/wassette" /> </a>

Global Ranking

-
Trust ScoreMCPHub Index

Based on codebase health & activity.

Manual Config

{ "mcpServers": { "wassette": { "command": "npx", "args": ["wassette"] } } }