nano-mcp-termux

Zero-dependency, single-file MCP server for AI agents, natively running on Termux (Android), Raspberry Pi, and Linux.

🚀 Quick Start

Local (Termux / Linux)

cd /path/to/nano-mcp-termux
python3 nano_mcp_termux.py

Docker

docker build -t nano-mcp-termux .
docker run -i --rm nano-mcp-termux

Health check (one-shot, no MCP handshake)

python3 nano_mcp_termux.py --health

Related MCP server: Python MCP Toolkit Server

🛠️ Features

• ✅ Zero-dependency: No external packages required

• ✅ Single-file: All logic in one Python script

• ✅ Cross-platform: Works in Termux (Android), on Raspberry Pi, Linux, and inside Docker

• ✅ Container-ready: Dockerfile at repo root for Glama introspection

• ✅ Standard stdio framing: Newline-delimited JSON-RPC (official MCP transport)

• ✅ Version negotiation: Echoes client protocolVersion (2024-11-05 / 2025-06-18 / 2025-11-25), falls back to highest supported

• ✅ Graceful degradation: device_status never fails; unavailable inputs are marked, not crashed

• ✅ [lifecycle] No orphaned processes: every command runs in its own process group; timeouts kill the whole tree (SIGTERM → SIGKILL), never just the shell

• ✅ [lifecycle] Self-terminating: parent-process watchdog + stdin-EOF detection + optional idle timeout, so a dead client never leaves a zombie server behind

• ✅ [lifecycle] Phantom Process Killer aware: reports Android 12+ child-count risk with concrete mitigations

• ✅ [paths] Android/Termux path adapter: resolves /sdcard ↔ /storage/emulated/0 ↔ $HOME/storage/shared, detects noexec mounts, case-insensitive filesystems, and shell-quoting hazards

🧩 Tools Overview

🔗 Protocol Surface

🔄 Why 1.1.0: the orphan-process bug

Version 1.0.0 ran commands with subprocess.run(..., timeout=...). On timeout, Python terminates only the direct child — the sh -c wrapper. Anything the shell had already spawned is reparented to init and survives forever. On Android that is the exact leak class that trips the Phantom Process Killer and can get the whole app group killed.

1.1.0 fixes this at the root: commands are spawned with start_new_session=True and torn down with os.killpg(pgid, SIGTERM) → SIGKILL, so the entire process tree dies together.

The repository ships a reproducible A/B regression test for it:

python3 test_lifecycle_orphan.py
# current  nano_mcp_termux.py           leaked_grandchildren=0
# legacy   nano_mcp_termux_v10_backup.py leaked_grandchildren=1   <- the bug
# PASS: current server leaves 0 orphaned grandchildren after timeout

✅ Tests

python3 test_client.py            # 32 protocol / tool / lifecycle assertions
python3 test_lifecycle_orphan.py  # orphan-leak A/B regression (1.0.0 vs 1.1.0)

⚙️ Environment variables

🔗 Links

• Original repository: Lmeng486/nano-mcp-termux

• Verification report: awesome-termux-mcp

• Measured overhead report (this server as subject under test, all numbers from a real device): MCP on Mobile: Measured Overhead Report

This server is designed to pass Glama introspection checks and serve as a lightweight MCP implementation for mobile and edge devices.