Bench

USB hardware discovery for your AI tools.

Bench is a native macOS MCP server that gives AI tools like Claude Code, Cursor, and Windsurf visibility into connected USB hardware. It identifies devices, finds serial ports, and recognizes common maker boards — so your AI assistant knows what's on your bench.

No API keys. No drivers. One command to install.

What it does

22 tools across four categories:

Discovery

Tool	Description
ping	Health check — returns server status, version, macOS version
list_usb_devices	List all connected USB devices with vendor, type, speed, serial
get_device_info	Detailed info on a specific device by serial, location ID, or name
identify_device	Smart identification of 83+ known maker/dev boards
list_serial_ports	Enumerate serial ports with USB device matching
hub_topology	USB hub tree view showing port hierarchy and connections
device_descriptors	Full USB descriptor chain — interfaces, endpoints, class codes
chip_detect	Detect exact chip type of ESP32/microcontroller via esptool

Monitoring

Tool	Description
monitor_events	Detect USB connect/disconnect events between calls
snapshot_state	Capture and diff USB device state snapshots
diagnose_device	Query system logs for USB errors on a specific device
power_info	Per-device power draw, bus budgets, charging detection

Management

Tool	Description
eject_device	Safely unmount and eject removable storage
tag_device	Persistent user-defined aliases for devices
port_reset	Reset a USB port to recover frozen devices
flash_firmware	Flash firmware via esptool/dfu-util/avrdude/UF2
hid_send	Send/receive raw HID reports

Serial Communication

Tool	Description
serial_open	Open a serial connection with configurable baud rate, data bits, parity
serial_read	Read available data from an open serial connection
serial_write	Write data or commands to an open serial connection
serial_close	Close an open serial connection
serial_monitor	Capture serial output for N seconds (boot logs, debug output)

Features

• Device classification — automatically categorizes devices as storage, input, hub, video, serial adapter, microcontroller, or debugger
• Serial port detection — maps USB devices to their /dev/cu.* serial ports (the #1 question makers ask)
• 83+ known boards — recognizes Arduino, Raspberry Pi, ESP32, Adafruit, SparkFun, Teensy, STM32, and common USB-serial chips
• Storage info — mount points, capacity, and free space for USB drives
• USB monitoring — event tracking, state snapshots, diagnostic log queries, and power analysis
• Firmware flashing — flash ESP32, STM32, Arduino AVR, and RP2040 boards directly
• HID interaction — send and receive reports from Stream Decks, macro pads, and custom HID devices
• Serial communication — open, read, write, and monitor serial ports with configurable baud rate, data bits, parity, and stop bits

Requirements

• macOS 14+ (Sonoma or later) on Apple Silicon
• An MCP-compatible AI tool (Claude Code, Cursor, Windsurf, etc.)
• For building from source: Xcode 16.3+ / Swift 6.1+

Install

Homebrew (recommended)

brew install seayniclabs/tap/bench

From source

git clone https://github.com/seayniclabs/bench.git
cd bench
swift build -c release
codesign --force --sign - --entitlements Sources/Bench/Bench.entitlements .build/release/Bench

The binary is at .build/release/Bench.

Add to Claude Code

claude mcp add bench -- $(which bench)

Or add manually to ~/.claude.json:

{
  "mcpServers": {
    "bench": {
      "command": "/path/to/bench",
      "args": []
    }
  }
}

Usage

Once connected, just talk to your AI tool:

• "What USB devices are connected?"
• "What port is my Arduino on?"
• "Identify the device on /dev/cu.usbserial-2120"
• "Eject the Samsung T7"
• "Show me all storage devices"
• "Open a serial connection to /dev/cu.usbserial-2120 at 9600 baud"
• "Monitor the serial output from my ESP32 for 10 seconds"

How it works

Bench uses Apple's IOKit framework to enumerate USB devices natively on macOS. It enriches results with serial port detection (/dev/cu.* scanning), storage info (diskutil), and a built-in database of known maker boards. It communicates with AI tools over stdio using the Model Context Protocol (JSON-RPC).

AI Tool  --stdio/JSON-RPC-->  Bench  --IOKit-->  USB Device Tree
                                     --diskutil-->  Storage Info
                                     --/dev/cu.*-->  Serial Ports
                                     --DeviceDB-->  Board Recognition

No special permissions needed. IOKit USB enumeration works without entitlements from a CLI binary.

Building

swift build             # debug build
swift build -c release  # release build
swift test              # run tests

Bench requires Swift 6.1+ and targets macOS 14+.

Using with a Gateway

If you're running multiple MCP servers, route them through a gateway like tbxark/mcp-proxy to manage all child processes from a single persistent service. The proxy handles process lifecycle, centralized config, and crash recovery — each server still gets its own SSE endpoint but you manage everything from one config file instead of scattered Claude Code entries.

For a full walkthrough of how this works in practice, see The Hidden Cost of a Loaded MCP Stack on charlieseay.com.

License

MIT

Credits

Built by Seaynic Labs.