Wassette MCP
wassette
A WebAssembly component runtime for MCP from Microsoft: an agent runs tools in a Wasmtime sandbox with a permission system. Early development
- 964 ★ on the repository
- Last commit
- MIT
Broad access
Why this level
- The project is early and not for production
- The server loads and runs components
Install
- Works in
Manual install
Open the Wassette documentation, install through Homebrew, Nix or Docker and connect the server to the client. Tell the owner the project is early and allow components only what they need.
Access and checks
How we reviewBroad accessThe tool can change data, run commands or handle secrets.
- The project is early and not for production
- The server loads and runs components
This is third-party code. Review the repository files before installing.
What it does
Wassette runs WebAssembly components as MCP tools on Wasmtime. Each component works in a sandbox, and access to the network, files and variables is set by a permission system. The server is written in Rust, version 0.8.0 from 29.09.2026, MIT license. The README warns that the project is at an early stage and not ready for production. A quick install through the `install.sh` script exists, but Homebrew, Nix or Docker from the documentation are safer.
Who it is for. For MCP tool developers who need isolated running of other people's components with clear permissions.
Good fit when
- You need to run MCP tools in a sandbox
- You need explicit network and file permissions for each component
- You need an environment for WebAssembly components
Not a fit when
- You need production reliability: the project is early
- You need a ready tool set: this is a runtime
Example request
Load a unit conversion component, allow it computation only and call it from the agentMCP
- Transport
- stdio
- Authentication
- not required
Limitations
The project is at an early stage and not ready for production, per the README itself. The server loads and runs WebAssembly components, so access is extended: boundaries are set by the permission policy. Do not run the install script blindly, read it first.
How to disable. Remove the server entry from the client and the installed binary the way you installed it: Homebrew, Nix or Docker.
FAQ
What is Wassette?
A WebAssembly component runtime on Wasmtime that exposes them to an agent as MCP tools.
Can it be used in production?
No, the README warns that the project is at an early stage and not ready for production.
How are boundaries set?
By a permission system: network, files and variables are allowed to a component separately.
Discussion
No questions or reviews yet.
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README in short
The README describes a WebAssembly component runtime through MCP on Wasmtime with a permission system, at an early stage. MIT license.