Robot Motion

Use this skill after a robot URDF exists and the task needs local motion behavior: IK, path planning, MoveIt configuration, websocket motion-server debugging, or ROS dependency setup. Any valid repo-local .urdf can be used when gen_motion() names links, joints, frames, and end effectors that exist in that file.

Workflow

1. Start from an existing valid .urdf.
2. Generate motion artifacts from a Python source with zero-arg gen_motion() using scripts/gen_motion_artifacts/cli.py.
3. Verify the local motion environment with scripts/check-motion-server.sh when it may already exist; run scripts/setup.sh only when dependencies are missing or stale.
4. Run the websocket motion server with scripts/run-motion-server.sh.
5. Test protocol, artifact generation, and provider logic before handing off motion behavior.
6. For CAD Explorer handoff of motion-enabled .urdf entries, defer to the CAD skill and keep motion-specific metadata here.

CAD Explorer Handoff

Read .agents/skills/cad/SKILL.md, then only load its references/rendering-and-explorer.md when a task needs an Explorer URL. If unavailable, use cad-skill. Do not duplicate Explorer startup or URL syntax in this skill. Link the repo-local .urdf when motion artifacts or URDF targets were generated or changed, or when the user asks for browser review. Keep motion-specific Explorer metadata and motion-server behavior here.

Commands

Run from the robot project repository root. If the current working directory is somewhere else, set ROBOT_MOTION_REPO_ROOT to the robot project root.

python .agents/skills/robot-motion/scripts/gen_motion_artifacts/cli.py <robot-urdf-source.py> --summary

.agents/skills/robot-motion/scripts/setup.sh
.agents/skills/robot-motion/scripts/check-motion-server.sh
.agents/skills/robot-motion/scripts/run-motion-server.sh

The runtime is host-agnostic but Conda/RoboStack/Jazzy-based. The setup script creates or updates the dedicated conda environment from environment.yml, installs server/ in editable mode, and runs motion_server --check. Use any conda-compatible installation available through ROBOT_MOTION_CONDA_EXE, CONDA_EXE, PATH, or a common Miniforge/Miniconda/Anaconda install root. Do not install ROS or MoveIt packages into the repo CAD .venv, system Python, or system package managers.

Use ROBOT_MOTION_REPO_ROOT, ROBOT_MOTION_CONDA_ENV_NAME, ROBOT_MOTION_CONDA_EXE, ROBOT_MOTION_HOST, or ROBOT_MOTION_PORT only when a task needs non-default repository root, environment, conda executable, host, or port settings.

Motion Artifacts

Use references/motion-artifacts.md when creating or editing gen_motion() envelopes, motion-owned sidecars, generated file expectations, or solve-vs-plan command choices.

Motion Server

The browser talks to motion_server over a direct local websocket, defaulting to ws://127.0.0.1:8765/ws. Vite does not start or supervise the server.

The server package lives in server/. It validates requested URDF files against repo-local robot-motion explorer metadata and robot-motion/motion_server.json, loads MoveIt sidecars from robot-motion/, and dispatches urdf.solvePose / urdf.planToPose to providers.

Troubleshooting

If check-motion-server.sh cannot find conda, locate an existing */bin/conda and rerun with ROBOT_MOTION_CONDA_EXE=/path/to/conda. Do not run setup merely because conda discovery failed.

In sandboxed agent environments, binding or connecting to the local websocket may fail with PermissionError on 127.0.0.1:<port>. Rerun the server or smoke-test command with the environment's approved out-of-sandbox/local-network mechanism; change ROBOT_MOTION_PORT only when the port is actually occupied.

Tests

Run focused tests after changes:

PYTHONPATH=.agents/skills/robot-motion/server ./.venv/bin/python -m unittest discover .agents/skills/robot-motion/server/tests
PYTHONPATH=.agents/skills/robot-motion/scripts ./.venv/bin/python -m unittest discover .agents/skills/robot-motion/scripts/gen_motion_artifacts/tests

MoveIt adapter tests should stay isolated so they pass without a sourced ROS shell unless a test explicitly requires ROS.

References

• Motion artifact specs: references/motion-artifacts.md