BCR 7-DOF arm — device market

Install

Three ways to run this device. Each one serves its fake backend: no instrument, no simulator install and no upstream checkout.

OpenAI4S (one command)

shell

openai4s lab add robots/blackcoffeerobotics__bcr_arm

Installs the device into the OpenAI4S Lab on its fake backend and starts it. First time? See setup below.

Or, in the workbench, open the Lab tab → Market → Install.

Standalone MHS endpoint

shell

git clone --depth 1 https://github.com/PKU-YuanGroup/OpenMHS.git && cd OpenMHS
PYTHONPATH=MHS/sdk/src python3 -m mhs serve robots/blackcoffeerobotics__bcr_arm --port 7400
# in a second terminal, from the same directory:
PYTHONPATH=MHS/sdk/src python3 -m mhs describe --endpoint http://127.0.0.1:7400

Serves the device as an MHS endpoint on port 7400 from an OpenMHS clone (Python 3.10 or later, standard library only); describe prints what it offers.

Any MCP host (Claude Desktop, Cursor, …)

mcp configuration

{
  "mcpServers": {
    "bcr-arm": {
      "command": "python3",
      "args": [
        "-m",
        "mhs",
        "serve",
        "robots/blackcoffeerobotics__bcr_arm",
        "--mcp"
      ],
      "env": {
        "PYTHONPATH": "/path/to/OpenMHS/MHS/sdk/src"
      }
    }
  }
}

Add this server to the host's MCP configuration and replace /path/to/OpenMHS with the path of your OpenMHS clone. The host starts the server and talks to it on stdin and stdout.

What it does

Measures

joint_positions
joint_velocities
read_joint_state

Adjusts

Nothing declared.

Actions

follow_arm_trajectory: Send FollowJointTrajectory points; return the controller error_code/error_string
activate_trajectory_controller: The declared re-enable after a safety reset: switch joint_trajectory_controller on again through /controller_manager/switch_controller (STRICT), so the trajectory the e-stop dropped is not resumed. On activation the controller holds the state it starts from: the last command-interface values when set_last_command_interface_value_as_state_on_activation (true by default) applies and every state interface has a command interface, else the measured joints. With this deployment's position-only command interface (position and velocity states) that is the measured position; a configuration that also commanded velocity would hold the last position command, which can differ from the measured position

Names as the driver declares them. Units, limits and the safety declaration are in the package's REFERENCE.md.

First-time setup

The OpenAI4S workbench with the OpenMHS lab, from a source checkout:

shell

# OpenAI4S workbench with the OpenMHS lab (source checkout)
git clone --recursive https://github.com/PKU-YuanGroup/OpenAI4S.git
cd OpenAI4S && ./setup.sh && source .venv/bin/activate
openai4s lab add robots/blackcoffeerobotics__bcr_arm
openai4s serve        # open the Lab tab

The standalone endpoint and the MCP server need only an OpenMHS clone and Python 3.10 or later. More in the market's getting-started guide and on the OpenAI4S host page.

Source and evidence

Upstream: blackcoffeerobotics/bcr_arm
Pinned commit: 9bd3d60b306b
Licence: Apache-2.0
Stars: 88
Evidence: contract_checked on the fake backend
Backends: fake

The driver package MHS/drivers/robots/blackcoffeerobotics__bcr_arm wraps the upstream code at the pinned commit. Its REFERENCE.md documents the full contract: every value, action, unit, limit and the safety declaration.