Mcp-NixosSAFE
MCP-NixOS - Model Context Protocol Server for NixOS resources
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
[](https://mcptoplist.com/server/glama%2Futensils%2Fmcp-nixos)
[](https://github.com/utensils/mcp-nixos/actions/workflows/ci.yml) [](https://codecov.io/gh/utensils/mcp-nixos) [](https://pypi.org/project/mcp-nixos/) [](https://flakehub.com/flake/utensils/mcp-nixos) [](https://www.python.org/downloads/) [](https://claude.ai)
Quick Start
🚨 No Nix/NixOS Required! Works on any system - Windows, macOS, Linux. You're just querying APIs.
Option 1: uvx (Recommended)
[](https://cursor.com/install-mcp?name=nixos&config=eyJjb21tYW5kIjoidXZ4IG1jcC1uaXhvcyJ9)
{
"mcpServers": {
"nixos": {
"command": "uvx",
"args": ["mcp-nixos"]
}
}
}Option 2: Nix
[](https://cursor.com/install-mcp?name=nixos&config=eyJjb21tYW5kIjoibml4IHJ1biBnaXRodWI6dXRlbnNpbHMvbWNwLW5peG9zIC0tIn0%3D)
{
"mcpServers": {
"nixos": {
"command": "nix",
"args": ["run", "github:utensils/mcp-nixos", "--"]
}
}
}Opti
a134bac4ede4OBSERVED · 2026-09-27Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.
claude mcp add mcp-nixos-website -- npx -y [email protected]
{
"mcpServers": {
"mcp-nixos-website": {
"command": "npx",
"args": [
"-y",
"[email protected]"
]
}
}
}Exposed tools (1)
1 read · 0 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
nix_versions | read | Get package version history from NixHub.io. |
Trust audit
SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | WARN |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | PASS |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- none-observed
- Network
- declared (6 observation(s))
- Shell
- none-observed
- Dependencies
- not all pinned
- Secrets in source
- none-found
Findings (13)
help = "start the MCP server over HTTP (http://127.0.0.1:8000/mcp)";
.envrc
.pre-commit-config.yaml
.release-please-manifest.json
CLAUDE.md
result = await nix_fn(action="info", query="../../etc/passwd", source="nix-dev")
# HTTP (default endpoint: http://127.0.0.1:8000/mcp)
# Run an HTTP MCP server at http://127.0.0.1:8000/mcp
- `MCP_NIXOS_TRANSPORT=http` enables HTTP mode (default endpoint: `http://127.0.0.1:8000/mcp`)
# Start with defaults: http://127.0.0.1:8000/mcp
@mariozechner/pi-ai, @mariozechner/pi-coding-agent, @types/node, typescript
@types/node, vitepress, vue, vue-tsc
- **Survive non-UTF-8 `.env` in CWD** (#144, #145): `mcp_nixos/__init__.py` now defaults `FASTMCP_ENV_FILE` to `os.devnull` via `os.environ.setdefault`, before any submodule imports fastmcp. mcp-nixos
Gates applied: no_behavioural_pass.
a134bac4ede4full audit observations/trust-audit/mcp-server/utensils__mcp-nixos.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-09-27 | a134bac4ede4 | SAFE | B | 89 | first audit |
Questions
What is the Mcp-Nixos MCP server?
MCP-NixOS - Model Context Protocol Server for NixOS resources
What tools does Mcp-Nixos expose?
1 in total: 1 read-only, 0 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is Mcp-Nixos safe to connect to an agent?
The audit found nothing in the source that contradicts what it says it does, and graded it B (89/100). Grade A is held back for packages that have also passed a sandboxed behavioural run, which is why a clean server reads B.
What credentials does Mcp-Nixos need?
No credential environment variables were found in its source, so it appears to need none.
How current is this page?
The grade is for one exact copy of the source (a134bac4ede4), read on 2026-09-27. The repository is watched and re-audited when it changes.