mcpd Linux

Linux MCP Server — exposes 100+ Linux system administration tools as an MCP (Model Context Protocol) server.

mcpd runs exclusively over standard input/output (stdio) and is designed to be executed by neurond (federation proxy), not exposed directly to the network.

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Architecture

┌──────────────────────────────────────┐
│  mcpd (stdio)                        │
│                                      │
│  ┌────────────┐  ┌────────────────┐  │
│  │            │  │  tools/        │  │
│  │ server.rs  │  │                │  │
│  │ (Router)   │  │  system.rs     │  │
│  │            │  │  network.rs    │  │
│  └────────────┘  │  file.rs       │  │
│                  │  container.rs  │  │
│  ┌────────────┐  │  package.rs    │  │
│  │ linux/     │  │  identity.rs   │  │
│  │            │  │  storage.rs    │  │
│  │ systemd.rs │  │  schedule.rs   │  │
│  │ network.rs │  │  security.rs   │  │
│  │ desktop.rs │  │  ...           │  │
│  └────────────┘  └────────────────┘  │
└──────────────────────────────────────┘
         ▲
         │ stdio
         │
    neurond (federation proxy)

• server.rs — MCP server core, handles routing requests natively via stdio
• tools/ — One module per tool domain. Input validation, pure Rust logic
• linux/ — Low-level OS access: D-Bus proxies (systemd, desktop), Netlink, /proc and /sys parsing
• types.rs — Typed #[derive(Serialize)] response structs for all tools (compile-time field safety)
• daemon.rs — PID file management and graceful SIGTERM/SIGINT shutdown
• deploy/mcpd.service — systemd unit for standalone testing and documenting the expected security context

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Tools

Domain	Tools	Description
system.*	info, reboot, sysctl, env, uptime	System info and control
process.*	list, inspect, kill, signal, top, tree, nice	Process management
service.*	list, status, start, stop, restart, logs, enable	systemd unit control
log.*	tail, search, stream, units	journald log access
network.*	interfaces, ports, connections, dns, firewall, routing	Network stack
file.*	read, write, info, search, mkdir, chmod, tail	File operations
container.*	list, inspect, logs, exec, start, stop	Docker containers
package.*	list, search, info, install, remove, update	APT package management
identity.*	users, groups, whoami	User/group info
storage.*	disks, mounts, usage, smart	Disk and SMART
schedule.*	list, add, remove	Crontab management
security.*	certs, open_ports, suid	Security checks
hardware.*	pci, usb	Hardware enumeration
desktop.*	notifications, clipboard, media, windows, settings, apps	Desktop integration
time.*	info, sync	NTP time info

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Security

• Tool Segregation — Designed to be run behind a proxy like neurond which handles mTLS, authentication, and policy checks.
• Input validation — Shell metacharacters rejected. Path traversal blocked with canonicalization.
• Path allowlist — File operations restricted to safe prefixes. Sensitive files always blocked.
• Localhost only — Executed via stdio locally. Never exposed to the network directly.

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Getting Started

Prerequisites

• Linux with systemd (Debian 12 / Ubuntu 22.04+)
• Rust 1.75+
• D-Bus system socket (standard on systemd hosts)
• For container tools: Docker daemon
• For desktop tools: D-Bus session socket

Build & Run

git clone https://github.com/cortexd-labs/mcpd.git
cd mcpd
cargo build --release

# Run locally (uses stdio transport)
cargo run

Server communicates directly via stdio.

Testing

cargo test          # 198 tests
cargo clippy -- -D warnings

Test with the standard MCP Inspector:

npx -y @modelcontextprotocol/inspector
# Choose stdio transport, select mcpd binary path

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Related Projects

• neurond — Federation proxy that aggregates mcpd and other MCP servers under namespaced prefixes
• cortexd — Fleet orchestrator (planned)

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License

MIT