What is mcp-firewall?
mcp-firewall is a MCP server by behrensd that deterministic security proxy for MCP that intercepts tool calls, enforces YAML policies, scans for secret leakage and logs everything. It is listed under Security and has 5 GitHub stars.
| Type | Mcp server |
|---|---|
| Author | behrensd |
| Repository | behrensd/mcp-firewall |
| Popularity | 5 GitHub stars |
| Category | Security |
| Security | Low risk (96/100) |
| Rank | #2,243 of 4,418 MCP servers; #111 in Security |
| License | Apache-2.0 |
| Last commit | 2026-09-19 |
| Runs | Locally |
| Language | TypeScript |
| Platforms | macOS, Windows, Linux |
Is mcp-firewall safe to install?
mcp-firewall 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 mcp-firewall?
- 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/behrensd/mcp-firewall
- 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 mcp-firewall -- <command from README> claude mcp add --transport http mcp-firewall <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 mcp-firewall for you:
Add the "mcp-firewall" MCP server from https://github.com/behrensd/mcp-firewall 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.