---

name: newton description: "Use Newton physics engine APIs for robotics simulation, solvers, contacts, asset import/export, sensors, viewers, examples, and repository maintenance." disable-model-invocation: true metadata: disco-role: operating license: Apache 2.0

Newton repo skill

Use this skill when a task involves Newton, newton-physics, the Python newton package, Warp-backed physics simulation, robotics/contact/deformable solver workflows, URDF/MJCF/USD import, Newton examples, or Newton repository maintenance.

Start here

1. Confirm install/backend state with scripts/check_newton_env.py.
2. For a tiny public simulation check, run scripts/newton_smoke.py --device cpu --steps 2.
3. Route to the focused sub-skill below.
4. If the user is editing Newton source, also read references/development-maintenance.md.
5. If behavior depends on version-sensitive details, read references/repo-provenance.md.

Installation and backends

Read references/install-and-backends.md before installing optional extras or diagnosing CUDA/RTX/Torch/USD/MuJoCo issues. Base Newton requires warp-lang; optional workflows use extras such as newton[sim], newton[importers], newton[examples], newton[onnx], newton[rtx], newton[torch-cu12], newton[torch-cu13], and newton[notebook].

Use CPU for first smoke checks unless the user specifically asks for CUDA, RTX, or Torch behavior. A CPU pass does not prove GPU performance.

Sub-skill routing

Task	Read
Build a model, add bodies/shapes/joints, allocate states/controls/contacts, replicate worlds, or write a minimal simulation loop	sub-skills/modeling-simulation/SKILL.md
Choose/configure solvers, CollisionPipeline, MuJoCo contacts, SDF/hydroelastic contacts, contact material tuning, or deterministic/GPU solver behavior	sub-skills/solvers-contacts/SKILL.md
Import URDF/MJCF/USD assets, diagnose optional importer deps, schema resolvers, mesh/remesh/heightfield utilities, or USD/File export artifacts	sub-skills/asset-import-export/SKILL.md
Use actuators, controllers, IK, ArticulationView, robot target layouts, sites for robotics control, or ONNX/Torch policy dependencies	sub-skills/robotics-control/SKILL.md
Use sensors, viewer backends, recording/replay, example CLI/browser, --viewer, --device, --test, headless visualization, or benchmark flags	sub-skills/sensors-visualization/SKILL.md
Diagnose cross-cutting install/import/backend or skill-staleness issues	references/troubleshooting.md, references/repo-provenance.md
Edit Newton source, tests, docs, examples, public API, or changelog	references/development-maintenance.md

Safe public commands

From this generated skill directory:

python scripts/check_newton_env.py --show-optional
python scripts/newton_smoke.py --device cpu --steps 2
python scripts/list_newton_examples.py --limit 20

Against an installed Newton environment, common package commands are:

python -m newton.examples --list
python -m newton.examples basic_pendulum --viewer null --device cpu --test

Use the user's Python environment for these commands. Do not assume this generated skill's construction environment is available.

Operating rules

• Use public imports: import newton, import warp as wp, and public submodules such as newton.solvers, newton.sensors, newton.viewer, newton.utils, newton.ik, and newton.actuators.
• Do not import from newton._src in user-facing code, docs, examples, or generated answers.
• Set newton.use_coord_layout_targets = True before constructing new robotics models that write position targets.
• Treat MuJoCo, USD/importers, RTX, ONNX, Torch, notebooks, and viewer stacks as optional extras; check dependencies before running examples.
• Prefer tiny CPU smokes before long examples, GPU runs, downloads, or visualization.
• Never hide network, credential, external-service, or broad dependency installation behind a helper script.

Staleness and provenance

references/repo-provenance.md records the source commit, package version, evidence paths, and verification summary used to create this skill. Refresh this skill when Newton's public APIs, docs, examples, dependency extras, or solver/importer behavior change.