DP100 MCP Server

This repository contains a local stdio MCP server for the ALIENTEK / 正点原子 DP100 digital power supply. It exposes DP100 status and output-control operations as MCP tools so an AI agent can safely read telemetry and control bench power during hardware bring-up.

This README is written primarily for AI agents. Follow it as the source of truth when installing this MCP server on a Linux host.

What this MCP does

The server talks to the DP100 over USB HID and registers the following MCP tools:

Tool	Purpose
dp100_get_device_info	Read DP100 model, hardware/app/bootloader versions, serial metadata.
dp100_get_status	Read live telemetry: input voltage, output voltage/current, temperature, output state.
dp100_get_active_settings	Read active preset/setpoint: voltage, current, OVP, OCP.
dp100_get_system_info	Read system settings such as backlight and over-temperature threshold.
dp100_set_output	Set output enable state plus voltage/current/OVP/OCP in mV/mA.
dp100_output_on	Convenience tool: enable output with explicit target voltage/current.
dp100_output_off	Convenience tool: disable output while preserving the current setpoint.

Safety behavior in the server:

• Uses a process-wide lock so concurrent MCP calls do not interleave HID transactions.
• Rejects negative voltage/current/protection values.
• Reads the device-reported max output voltage before applying a setpoint and rejects requests above that limit.
• dp100_output_off turns output off without changing to an arbitrary high setpoint.

Supported environment

Known working environment:

• Linux host
• Python 3.10+
• DP100 connected over USB HID
• USB VID/PID: 2e3c:af01
• Python dependencies:
  • mcp
  • hidapi
  • crcmod

The device may appear as /dev/hidrawN. Do not hard-code /dev/hidraw4; the number can change across machines and reconnects. The server opens the device by VID/PID.

Install from GitHub

Use these commands on the machine that has the DP100 physically connected:

cd ~/dev
git clone https://github.com/lymzzyh/dp100-mcp.git
cd dp100-mcp
python3 -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt

If pip install hidapi fails, install the system HID/libusb development packages first, then retry:

sudo apt-get update
sudo apt-get install -y python3-venv python3-dev build-essential pkg-config libhidapi-dev libusb-1.0-0-dev
. .venv/bin/activate
pip install -r requirements.txt

Linux USB permission setup

If the AI agent is not running as root, install a udev rule so the agent user can open the DP100 HID device.

Create /etc/udev/rules.d/99-atk-dp100.rules:

sudo tee /etc/udev/rules.d/99-atk-dp100.rules >/dev/null <<'EOF'
SUBSYSTEM=="hidraw", ATTRS{idVendor}=="2e3c", ATTRS{idProduct}=="af01", MODE="0660", GROUP="plugdev", TAG+="uaccess"
EOF
sudo udevadm control --reload-rules
sudo udevadm trigger
sudo usermod -aG plugdev "$USER"

Then unplug/replug the DP100. If the user was just added to plugdev, log out and log back in, or restart the agent service/session.

Verify the device exists:

lsusb | grep -i '2e3c:af01' || true
ls -l /dev/hidraw*

Configure an AI agent MCP client

This server uses stdio transport. Configure the MCP client to run the repository-local Python interpreter and dp100_mcp.py.

Hermes Agent example

Add this to ~/.hermes/config.yaml:

mcp_servers:
  dp100:
    command: /home/YOUR_USER/dev/dp100-mcp/.venv/bin/python
    args:
      - /home/YOUR_USER/dev/dp100-mcp/dp100_mcp.py
    timeout: 30
    connect_timeout: 15

Replace /home/YOUR_USER/dev/dp100-mcp with the actual clone path.

Restart Hermes Agent after editing the config. Hermes should then expose tools with names similar to:

• mcp_dp100_dp100_get_status
• mcp_dp100_dp100_output_on
• mcp_dp100_dp100_output_off

Tool prefixes vary by client. The underlying MCP tool names are the names listed in What this MCP does.

Generic MCP stdio config shape

For other MCP clients, use equivalent stdio configuration:

{
  "mcpServers": {
    "dp100": {
      "command": "/home/YOUR_USER/dev/dp100-mcp/.venv/bin/python",
      "args": ["/home/YOUR_USER/dev/dp100-mcp/dp100_mcp.py"]
    }
  }
}

Manual verification for AI agents

Before relying on the MCP tools, verify the server can start and talk to the hardware.

1. Syntax/import check

cd ~/dev/dp100-mcp
. .venv/bin/activate
python -m py_compile dp100_mcp.py
python - <<'PY'
import dp100_mcp
print('import-ok')
PY

2. List MCP tools with mcporter

If Node.js is available, use mcporter:

cd ~/dev/dp100-mcp
npx -y mcporter list \
  --stdio "$PWD/.venv/bin/python $PWD/dp100_mcp.py" \
  --name dp100 \
  --schema

Expected result: the listed tools should include dp100_get_status, dp100_output_on, and dp100_output_off.

3. Read status

cd ~/dev/dp100-mcp
npx -y mcporter call \
  --stdio "$PWD/.venv/bin/python $PWD/dp100_mcp.py" \
  dp100_get_status \
  --output json

Expected result: JSON containing fields such as vin_mv, vout_mv, iout_ma, output_enabled, vin_v, vout_v, and iout_a.

4. Safe output control smoke test

Only run this if a safe load or no sensitive target is connected. Example: enable 1.0 V / 0.1 A with conservative OVP/OCP, then turn off:

cd ~/dev/dp100-mcp
npx -y mcporter call \
  --stdio "$PWD/.venv/bin/python $PWD/dp100_mcp.py" \
  dp100_output_on \
  voltage_mv:1000 current_ma:100 ovp_mv:5000 ocp_ma:500 \
  --output json

npx -y mcporter call \
  --stdio "$PWD/.venv/bin/python $PWD/dp100_mcp.py" \
  dp100_output_off \
  --output json

Operational guidance for AI agents

When using this MCP to control real hardware:

1. Always read dp100_get_status and dp100_get_active_settings before changing output.
2. Prefer dp100_output_off for emergency stop / power-down.
3. When enabling output, set explicit voltage_mv, current_ma, ovp_mv, and ocp_ma suitable for the attached target.
4. Use millivolts and milliamps. Do not pass volts/amps as floats.
5. Do not repeatedly toggle output in a tight loop; hardware targets may need discharge and boot timing margins.
6. If the device disappears, replug the DP100 and re-check udev permissions.
7. If multiple agents may access the same physical DP100, run only one MCP server instance or enforce external coordination.

Troubleshooting

hid.HIDException or permission denied

Likely cause: the user cannot open /dev/hidrawN.

Fix:

• Install the udev rule from Linux USB permission setup.
• Replug the DP100.
• Ensure the agent process is running under a user in the plugdev group or a desktop session with uaccess permissions.

No such device / device not found

Check:

lsusb | grep -i '2e3c:af01'

If not present, reconnect the DP100 USB cable and verify the cable supports data.

MCP tools do not appear in the AI client

Check:

• The MCP config path is correct.
• The command points to .venv/bin/python inside this repo.
• The args path points to dp100_mcp.py.
• The agent/client was restarted after config changes.
• python -m py_compile dp100_mcp.py passes.

Tool call hangs or fails intermittently

The DP100 HID protocol is synchronous. Avoid concurrent calls from multiple processes. This server serializes calls within one process, but it cannot protect against another independent process opening the same HID device.

Development notes

Run basic local checks:

cd ~/dev/dp100-mcp
. .venv/bin/activate
python -m py_compile dp100_mcp.py

The server entry point is:

python dp100_mcp.py

It runs an MCP stdio server and should normally be launched by an MCP client, not by a human terminal session.