Quick Start

Prerequisites

• ESP32 board (or any Arduino-compatible MCU)
• PlatformIO or Arduino IDE
• Node.js 18+
• Claude Desktop or any MCP-compatible agent (Claude Code, Gemini CLI, etc.)

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Step 1 — Choose a Transport

MCP/U supports two transports. Pick one based on your setup:

	Serial (USB)	WiFi TCP
Cable required	Yes	No
Board support	All	ESP32 / ESP8266
Setup complexity	Minimal	Needs SSID + password
Use case	Development	Deployment / wireless

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Step 2 — Flash Firmware

Clone the repo and flash the matching example:

Serial

git clone https://github.com/ThanabordeeN/mcpu
cd mcpu/firmware
pio run -t upload

Or open firmware/ in Arduino IDE and upload src/main.cpp.

The default example exposes:

• GPIO 2 — led (digital output)
• GPIO 5 — buzzer (digital output)
• GPIO 34 — sensor (ADC input)

WiFi TCP

Edit the credentials at the top of the sketch before uploading:

static const char*    WIFI_SSID     = "YOUR_SSID";
static const char*    WIFI_PASSWORD = "YOUR_PASSWORD";
static const uint16_t TCP_PORT      = 3000;

After flashing, open the Serial Monitor — the ESP32 prints its IP address on boot:

Connecting to WiFi....
IP: 192.168.1.42
TCP server listening on port 3000

Note that IP — you’ll need it in Step 4.

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Step 3 — Find your serial port

(Skip this step if you’re using WiFi TCP.)

Linux:

ls /dev/ttyUSB* /dev/ttyACM*

macOS:

ls /dev/tty.usbserial-*

Windows: Device Manager → Ports (COM & LPT)

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Step 4 — Add to your AI agent

The MCP/U client is published on npm — no local clone needed.

Claude Desktop

Serial — Linux / macOS (~/.config/claude/claude_desktop_config.json):

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": {
        "SERIAL_PORT": "/dev/ttyACM0"
      }
    }
  }
}

Serial — Windows (%APPDATA%\Claude\claude_desktop_config.json):

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": {
        "SERIAL_PORT": "COM3"
      }
    }
  }
}

WiFi TCP (replace IP with the one printed by your ESP32):

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": {
        "DEVICES": "mydevice:192.168.1.42:3000:tcp"
      }
    }
  }
}

Multiple devices (mix Serial and TCP freely):

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": {
        "DEVICES": "robot:/dev/ttyUSB0:115200,sensor:192.168.1.42:3000:tcp"
      }
    }
  }
}

---

Claude Code (CLI)

# Serial
claude mcp add mcpu -e SERIAL_PORT=/dev/ttyACM0 -- npx mcpu-client

# WiFi TCP
claude mcp add mcpu -e DEVICES=mydevice:192.168.1.42:3000:tcp -- npx mcpu-client

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Gemini CLI

Edit ~/.gemini/settings.json:

Serial:

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": { "SERIAL_PORT": "/dev/ttyACM0" }
    }
  }
}

WiFi TCP:

{
  "mcpServers": {
    "mcpu": {
      "command": "npx",
      "args": ["mcpu-client"],
      "env": { "DEVICES": "mydevice:192.168.1.42:3000:tcp" }
    }
  }
}

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OpenCode

opencode.json — Serial:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "mcpu": {
      "type": "local",
      "command": ["npx", "mcpu-client"],
      "enabled": true,
      "environment": { "SERIAL_PORT": "/dev/ttyACM0" }
    }
  }
}

WiFi TCP — replace SERIAL_PORT with DEVICES:

"environment": { "DEVICES": "mydevice:192.168.1.42:3000:tcp" }

Restart your agent. Claude can now control your MCU.

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Verify with MCP Inspector

SERIAL_PORT=/dev/ttyACM0 npx @modelcontextprotocol/inspector npx mcpu-client

Open the browser URL shown and try calling list_devices or gpio_write.

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Next Steps

• Firmware Guide — full McpIot API reference
• Client Guide — multi-device setup, TCP transport
• Protocol Spec — JSON-RPC wire format