Pymcuprog

MCP server wrapping pymcuprog so AI tools (Claude Code, Claude Desktop, etc.) can program Microchip AVR microcontrollers via natural language.

Supports USB HID debuggers (nEDBG, PICkit 4, Atmel-ICE, MPLAB Snap, …) and serial UART UPDI adapters.

Installation

No installation needed if you use uvx — it runs the server directly from PyPI on demand (see .mcp.json examples below).

To install as a persistent tool:

uv tool install pymcuprog-mcp

Or with pip:

pip install pymcuprog-mcp

From source:

git clone https://github.com/lucasgerads/pymcuprog-mcp
cd pymcuprog-mcp
pip install -e .

Configuration

The server is configured via environment variables. The two most important ones are PYMCUPROG_DEVICE (target MCU name, e.g. atmega4808) and PYMCUPROG_TOOL (debugger type, e.g. nedbg).

Variable	Description	Default
PYMCUPROG_DEVICE	Target device name (e.g. atmega4808, attiny416)	—
PYMCUPROG_TOOL	Debugger type (nedbg, pickit4, atmelice, snap, …)	any connected
PYMCUPROG_SERIALNUMBER	USB serial number substring (to pick a specific tool)	—
PYMCUPROG_SERIALPORT	Serial port for UART UPDI mode (e.g. /dev/ttyUSB0, COM3)	—
PYMCUPROG_BAUDRATE	Baud rate for serial UPDI mode	115200
PYMCUPROG_PROJECT_DIR	Default project directory for the build_and_flash tool	—

Setting PYMCUPROG_SERIALPORT switches the server into serial UPDI mode (uses a plain USB-serial adapter instead of a Microchip debugger).

.mcp.json examples

All examples use uvx, which downloads and runs the server directly from PyPI with no prior installation step.

USB HID debugger (nEDBG / Curiosity Nano)

{
  "mcpServers": {
    "pymcuprog": {
      "command": "uvx",
      "args": ["pymcuprog-mcp"],
      "env": {
        "PYMCUPROG_DEVICE": "atmega4808",
        "PYMCUPROG_TOOL": "nedbg"
      }
    }
  }
}

PICkit 4 or MPLAB Snap

{
  "mcpServers": {
    "pymcuprog": {
      "command": "uvx",
      "args": ["pymcuprog-mcp"],
      "env": {
        "PYMCUPROG_DEVICE": "attiny416",
        "PYMCUPROG_TOOL": "pickit4"
      }
    }
  }
}

Serial UART UPDI (cheap USB-serial adapter)

{
  "mcpServers": {
    "pymcuprog": {
      "command": "uvx",
      "args": ["pymcuprog-mcp"],
      "env": {
        "PYMCUPROG_DEVICE": "avr128da48",
        "PYMCUPROG_SERIALPORT": "/dev/ttyUSB0",
        "PYMCUPROG_BAUDRATE": "115200"
      }
    }
  }
}

Multiple tools on the same machine (select by serial number)

{
  "mcpServers": {
    "pymcuprog-board-a": {
      "command": "uvx",
      "args": ["pymcuprog-mcp"],
      "env": {
        "PYMCUPROG_DEVICE": "atmega4808",
        "PYMCUPROG_TOOL": "nedbg",
        "PYMCUPROG_SERIALNUMBER": "MCHP0001"
      }
    },
    "pymcuprog-board-b": {
      "command": "uvx",
      "args": ["pymcuprog-mcp"],
      "env": {
        "PYMCUPROG_DEVICE": "atmega4808",
        "PYMCUPROG_TOOL": "nedbg",
        "PYMCUPROG_SERIALNUMBER": "MCHP0002"
      }
    }
  }
}

Claude Code (via CLI)

claude mcp add pymcuprog -e PYMCUPROG_DEVICE=atmega4808 -e PYMCUPROG_TOOL=nedbg -- uvx pymcuprog-mcp

Available tools

Tool	Description
list_supported_devices	All device names pymcuprog knows (no hardware needed)
list_connected_tools	USB HID debuggers currently attached
ping	Read device ID bytes to verify connectivity
erase	Chip erase or erase a specific memory area
flash	Erase + write + verify + release in one call (recommended)
build_and_flash	Run make in a project directory, then flash the resulting .hex
write_hex	Program a .hex file with manual control over erase/verify steps
verify_hex	Compare target memory to a .hex file
read_memory	Read raw bytes from flash, EEPROM, fuses, etc.
write_memory	Write raw hex bytes to fuses, EEPROM, user_row, etc.
hold_in_reset	Hold target in reset
release_from_reset	Release target from reset
disconnect	Close the persistent debugger session
read_target_voltage	Measure target VCC
read_supply_voltage	Read debugger supply setpoint
set_supply_voltage	Set debugger supply voltage output
read_tool_info	Read debugger firmware/hardware info

Typical workflow: ping → flash or ping → build_and_flash

All programming tools accept optional device, tool, serialport, etc. parameters to override the environment variables on a per-call basis.