wassette

MCP server · GitHub · ★ 972 · graded 2026-10-23Source linked

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

No outside reports on file

Wassette adds a security layer but isn't a guarantee; treat all WebAssembly components as potentially risky code and only run those from trusted sources with careful monitoring.

Based on public adoption and transparency signals as of Oct 23, 2026. Our opinion, not a code audit or security guarantee.

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What it can access

Local filesNo local folder access notedLOW
Command executionNo shell command runner notedLOW
Network reachConnects to outside service APINOTED
CredentialsNo API token requiredLOW
Package sourceGitHub (microsoft/wassette)PUBLIC

Inferred from this listing’s public package details and description. Check the project’s source before installing.

Install

No npm or PyPI package is listed. Install from source: github.com/microsoft/wassette ↗

All setup options ↓

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About Wassette

Wassette is a runtime that executes WebAssembly Components through MCP (Model Context Protocol). It's designed with security in mind to safely run compiled WebAssembly code that can be called by AI agents or other applications.

Who it’s for

Developers who want to run untrusted or sandboxed code safely, or teams building AI agent systems that need to execute custom logic without full system access. It's most useful when you need isolation between different code modules.

Alternatives

wasmtime: A standalone WebAssembly runtime with security focus; less MCP-integrated but widely used
WasmEdge: Another sandboxed WebAssembly runtime with cloud-native features
Direct Python/JavaScript execution: If you control the code, running it natively may be simpler but offers no sandboxing

Setup

Check these steps against the project’s own instructions before running anything.

Follow the project's README at https://github.com/microsoft/wassette (opens external site) for installation and configuration instructions specific to your environment.

Why this grade

CC — Moderate risk signals

Signal-based grade (3/7 points): well starred on GitHub, public source code. This reflects adoption and transparency, not a code review.

Popularity and upkeep

33/100

GitHub stars: 972
Listing last refreshed: 2026-10-29

These are public popularity signals, not a maintenance check. Look at the repository’s commit history and open issues.

Security reports

No reports found for this package in our research (last checked 2026-10-29).

Check a specific version →

Risks to watch for

Code execution risk: Runs compiled WebAssembly which could contain malicious logic despite sandboxing claims; review all .wasm files before loading
Sandbox escape: Security boundaries in any runtime can have flaws; WebAssembly sandboxes are still actively researched for vulnerabilities
Data access: Components can read files and environment variables that the Wassette process has permission to access
MCP protocol attacks: Malformed or malicious MCP calls could trigger unexpected behavior or information leaks
Supply chain: If components come from untrusted sources, they may contain hidden functionality that seems legitimate

How to lower the risk

Least-privilege permissions

Run Wassette with minimal file system and network access
Don't give the process admin or root permissions

Network isolation

Disable outbound network access unless absolutely needed
Use firewall rules to block unexpected connections

Monitoring

Log all component loads and MCP calls for audit trails
Watch for unusual CPU, memory, or disk activity

Red flags to watch for

Components from unknown or unverified authors
Requests to access sensitive files or environment variables
Unexpected network connection attempts

Questions

How do I install Wassette?

Wassette does not publish a standalone npm or PyPI package. Clone or follow the setup instructions in its source repository at github.com/microsoft/wassette.

Are there security reports about Wassette?

No reports found for this package in our research (last checked 2026-10-29). Wassette currently holds Grade C (Moderate risk signals) based on public adoption and transparency signals. Key risk areas to watch include code execution risk, sandbox escape, data access.

Is Wassette actively maintained?

Wassette has 972 GitHub stars. Our directory data was last refreshed on 2026-10-29. Check recent commit activity, release tags, and open issues at github.com/microsoft/wassette before pinning it in production.

What are alternatives to Wassette?

Notable alternatives to Wassette include wasmtime (A standalone WebAssembly runtime with security focus), WasmEdge (Another sandboxed WebAssembly runtime with cloud-native features), Direct Python/JavaScript execution (If you control the code, running it natively may be simpler but offers no sandboxing). You can also compare Wassette side by side with other MCP servers in the Related tools section on this page.

Maintain or use Wassette? Show its live grade in your GitHub README, docs site, or run a check from the terminal before you install.

GitHub README Markdown:

markdown

[![AgentArmorHQ Risk Grade for Wassette](https://agentarmorhq.com/api/badge/microsoft-wassette)](https://agentarmorhq.com/skills/microsoft-wassette)

HTML embed:

html

<a href="https://agentarmorhq.com/skills/microsoft-wassette"><img src="https://agentarmorhq.com/api/badge/microsoft-wassette" alt="AgentArmorHQ Risk Grade for Wassette" height="20" /></a>

Terminal check:

terminal

curl -fsSL https://agentarmorhq.com/api/cli | node --input-type=module - check "microsoft-wassette"

Share with your security lead

Need sign-off to use wassette? Copy this note for Slack, a ticket or a pull request.

### AgentArmorHQ Security Review Memo: wassette
- **Listing URL:** https://agentarmorhq.com/skills/microsoft-wassette
- **Type:** App connector
- **Risk Grade:** Grade C (Moderate risk signals)
- **Outside Security Advisories on File:** 0
- **Public Adoption:** 972 GitHub stars

#### Permission & Blast-Radius Signals
- **Local files:** No local folder access noted
- **Command execution:** No shell command runner noted
- **Network reach:** Connects to outside service API
- **Credentials:** No API token required
- **Package source:** GitHub (microsoft/wassette)

#### Recommended Hardened Setup
- **Source Repo:** https://github.com/microsoft/wassette
- **Controls:** Pin an exact version in `.mcp.json`, scope access to a single workspace folder, and use a least-privilege read-only token where supported.

_Based on public adoption and transparency signals as of Oct 23, 2026. Our opinion, not a code audit or security guarantee._

Key facts

Type: App connector
Publisher: microsoft
Source code: github.com/microsoft/wassette
Est. context load: ~850 tokens / turn (~5 tool schemas, 0.43% of 200k context)
Popularity: 972 GitHub stars
Last updated: 2026-10-29
Last graded: 2026-10-23

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