What is assay?
assay is a MCP server by Rul1an that fail-closed policy-as-code proxy for MCP that denies risky tool calls, produces offline-verifiable evidence bundles and enforces egress via eBPF and Landlock. It is listed under Security and has 13 GitHub stars.
| Type | Mcp server |
|---|---|
| Author | Rul1an |
| Repository | Rul1an/assay |
| Popularity | 13 GitHub stars |
| Category | Security |
| Security | Low risk (96/100) |
| Rank | #1,572 of 4,418 MCP servers; #79 in Security |
| License | MIT |
| Last commit | 2026-10-17 |
| Stars this week | +1 |
| Runs | Locally |
| Language | Rust |
| Platforms | macOS, Windows, Linux |
Is assay safe to install?
assay scores 96/100 on the MCPMods security check: Low risk. No checks raised a concern. It passed 5 of 6 checks.
MCP server results come from listing signals: who publishes it, where your data goes and what it can do. The code itself is not scanned yet.
| Check | Result |
|---|---|
| Community-built server | Note |
| Runs on your machine only | Pass |
| No credentials mentioned | Pass |
| Read-only by description | Pass |
| No code execution | Pass |
| Source on GitHub | Pass |
How do I install assay?
- Find the launch command. The README says how the server starts (npx, uvx, docker or a remote URL) and which API keys it needs.
https://github.com/Rul1an/assay
- Add it to Claude Code. Replace the part after -- with the command from the README. Remote servers use --transport http with a URL.
claude mcp add assay -- <command from README> claude mcp add --transport http assay <server-url>
- Check it connected. This lists your MCP servers and their status.
claude mcp list
Or ask Claude to set it up
Paste this into Claude Code and it installs assay for you:
Add the "assay" MCP server from https://github.com/Rul1an/assay to Claude Code. Read its README for the launch command and any API keys I need, run claude mcp add, then check that it connects.