dart-python

DART Python: dartpy bindings, nanobind, wheels, and API patterns.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/dartsim/dart/dart-python
Any agent
npx skills add dartsim/dart --skill dart-python
Clone the repo
git clone --depth 1 https://github.com/dartsim/dart

Made for: Claude Code, Codex.

Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 455 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00020 $0.00455
Opus 5 $0.00010 $0.00228
Sonnet 5 $0.00004 $0.00091
Haiku 4.5 $0.00002 $0.00046

Measured today against content hash 99cd959d24cc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dart-python scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/dart-python/SKILL.md · 67 lines

What it actually says

DART Python Bindings (dartpy)

Load this skill when working with Python bindings or dartpy.

When a binding exposes or changes model/scene loading, dynamics, collision/contact/constraints, simulation stepping, GUI/rendering output, or a visual example, also load dart-verify-sim. Pair a focused Python text/behavior oracle with an assessed, claim-tied headless capture; document a visual exception when rendering is unavailable or not applicable.

Quick Start

import dartpy as dart

world = dart.World()
skel = dart.io.read_skeleton("dart://sample/urdf/KR5/KR5 sixx R650.urdf")
world.add_skeleton(skel)

for _ in range(100):
    world.step()

Full Documentation

For complete Python bindings guide: docs/onboarding/python-bindings.md

For module-specific details: python/AGENTS.md

Quick Commands

pixi run build-py-dev    # Build for development
pixi run test-py         # Run Python tests
pixi run generate-stubs  # Generate type stubs

Wheel Building

pixi run -e py314-wheel wheel-build
pixi run -e py314-wheel wheel-repair  # Linux only
pixi run -e py314-wheel wheel-test

Key Patterns

  • snake_case preferred (camelCase emits DeprecationWarning)
  • NumPy arrays auto-convert to Eigen types
  • GUI requires DART_BUILD_GUI=ON

Key Files

  • Package config: pyproject.toml
  • Build system: python/dartpy/CMakeLists.txt
  • Type stubs: python/stubs/dartpy/
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. today First seen · 67 lines · 20 tokens per session scan A 99cd959d24cc

Subscribe to this mod's changes

dart-python is a skill published in the GitHub repository dartsim/dart (1,199 stars, last pushed today), licensed BSD-2-Clause. It adds 20 tokens to every session and 455 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-01.

Related

Other skills, from other repositories

cad

Create, modify, inspect, and validate STEP-first parametric CAD parts and assemblies. Use for natural-language CAD specs, reference images, 2D technical drawings, STEP/STP generation or direct inspection, Python CAD source, source-level joints, selector references, geometry facts, measurements, mating deltas…

earthtojake/text-to-cad · 79 tokens

implicit-cad

Create, edit, render, and snapshot browser-native implicit CAD .implicit.js and .implicit.mjs files using GLSL signed-distance fields, shader primitives, smooth booleans, TPMS fields, and direct CAD Viewer raymarch rendering. Experimental.

earthtojake/text-to-cad · 56 tokens

urdf

URDF robot description authoring and validation. Use when creating, editing, inspecting, validating, or debugging .urdf files, robot links, joints, limits, inertials, visual/collision geometry, mesh references, frame conventions, or robot-description artifacts. Use the SRDF skill for MoveIt2 semantic groups and…

earthtojake/text-to-cad · 106 tokens

dfam-check

Measure mesh files against Design for Additive Manufacturing (DfAM) rules and report printability findings per process (FDM, SLS, SLA/DLP, metal PBF, MJF). Use when the user asks whether a part is printable, wants overhang/wall-thickness/support analysis of an .stl, .obj, .ply, or .3mf mesh, wants a build-orientation…

earthtojake/text-to-cad · 111 tokens

gcode

Generate, inspect, dry-run, and statically validate plain FDM .gcode from 3D mesh files by orchestrating real slicer CLIs. Use when Codex needs to slice .stl, .obj, unsliced .3mf, .ply, .glb, or .gltf into printer-profiled G-code, discover local slicer backends, inspect whether a mesh is slice-ready, or validate…

earthtojake/text-to-cad · 102 tokens

step-parts

Find, evaluate, and download common purchasable CAD parts from step.parts, including named off-the-shelf actuators, servos, motors, electronics boards, connectors, screws, bolts, nuts, washers, bearings, standoffs, and other catalog components. Use when Codex needs to search the hosted step.parts catalog before…

earthtojake/text-to-cad · 119 tokens