Wassette MCP Server by Microsoft: Setup for Claude, Cursor and Other Apps

• Loads a new tool from a file or an online registry

  Downloads or opens a WebAssembly component and adds its functions to your assistant as new tools. The path can be a local file or an OCI registry address.

  Try: “Load the time component from oci://ghcr.io/microsoft/time-server-js:latest.”

  Write · load-component

• Removes a loaded tool

  Unloads a component by ID so its tools disappear from your assistant.

  Try: “Unload the time component.”

  Write · unload-component

• Lists the components you have loaded

  Shows which components are loaded right now.

  Try: “Which components are loaded?”

  Read · list-components

• Shows what a component is allowed to do

  Returns the permission policy of one component, covering its storage, network and environment access.

  Try: “Show the policy for the fetch component.”

  Read · get-policy

• Lets a component read or write a path

  Gives a component access to a file path, either read-only or read and write.

  Try: “Let the file-notes component read /tmp/notes.”

  Write · grant-storage-permission

• Lets a component call specific hosts

  Allows a component to make network requests to the hosts you name.

  Try: “Allow the weather component to reach api.weather.example.”

  Write · grant-network-permission

• Lets a component read named environment variables

  Allows a component to read the environment variables you name. Be careful with keys and tokens.

  Try: “Let the github component read GITHUB_TOKEN.”

  Write · grant-environment-variable-permission

• Takes back a component's access to a path

  Removes both read and write access a component had to a path.

  Try: “Revoke the file-notes component's access to /tmp/notes.”

  Write · revoke-storage-permission

• Takes back a component's access to a host

  Stops a component from making requests to a host you granted earlier.

  Try: “Revoke the weather component's network access.”

  Write · revoke-network-permission

• Takes back access to an environment variable

  Stops a component from reading an environment variable you granted earlier.

  Try: “Revoke the github component's access to GITHUB_TOKEN.”

  Write · revoke-environment-variable-permission

• Clears all permissions a component has

  Takes away every permission you granted to a component and returns it to its default state.

  Try: “Reset all permissions for the fetch component.”

  Write · reset-permission

• Lists components you can fetch and load

  Searches the list of known components, optionally by a word you give.

  Try: “Search for components that deal with time.”

  Network · search-components

Watch out for

• The assistant can load code from the internet

  The load tool fetches a component from a file or OCI registry and runs it. Load only components you trust and check the address first. github.com

• The assistant can grant permissions itself

  The grant tools give components access to paths, hosts and environment variables, so a mistaken approval widens what runs. Review each grant, especially tokens and write access. github.com

• The tool list changes as you load components

  Every loaded component adds its own tools, and their effects depend on that component. Read its policy with the policy tool before you use it. github.com

• Components run in a Wasmtime sandbox

  The project says components run in a WebAssembly sandbox with allow and deny lists for files and network. The repository warns it is early development and not production ready. github.com

• Optional HTTP mode binds to localhost

  The serve command's HTTP address defaults to 127.0.0.1:9001. Change it only if you add your own protection. github.com

Security advisories