What is cad-modeling-fusion?

A workflow for turning natural-language 3D modeling requests into parametric CAD specifications and scripts for Autodesk Fusion, FreeCAD, or OpenSCAD.

Use it to create, modify, validate, and export CAD models for formats such as STEP, STL, OBJ, and F3D, including models intended for 3D printing.

It helps translate a shape or manufacturing request into a checked model plan and code without manually building every step in a CAD tool.

cad-modeling-fusion — Skill for Claude Code and Codex by Foster1202

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.

Any agent

npx skills add Foster1202/cad-modeling-fusion-skill --skill cad-modeling-fusion-skill

Clone the repo

git clone --depth 1 https://github.com/Foster1202/cad-modeling-fusion-skill

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill/github.svg)](https://agentmods.dev/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill)

Your own site

<a href="https://agentmods.dev/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill"><img src="https://agentmods.dev/badge/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill"><img src="https://agentmods.dev/badge/skills/foster1202/cad-modeling-fusion-skill/cad-modeling-fusion-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,110 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original 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.

Model	Per session	Once invoked
Fable 5.1	$0.00066	$0.01110
Opus 5.5	$0.00026	$0.00444
Sonnet 5.5	$0.00013	$0.00222
Haiku 4.5	$0.00007	$0.00111

Measured 2mo ago against content hash 26f6cb52fc58, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cad-modeling-fusion 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 2mo ago.

The scan reads SKILL.md. This mod also ships 2 executable files (assets/templates/freecad_script_template.py, assets/templates/fusion_script_template.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CAD Modeling Fusion Skill

Use this skill when a user wants a parametric CAD model, a validated CAD model specification, generated Autodesk Fusion Python code, fallback FreeCAD/OpenSCAD code, or export guidance for STEP/STL/OBJ/F3D workflows.

Do not use this skill for pure mesh sculpting, animation, rendering-only scenes, destructive edits to user CAD files, or executing untrusted generated code without explicit confirmation.

Workflow

Parse the request into a ModelSpec JSON object.
Ask clarifying questions only when critical dimensions, units, or manufacturing requirements are missing and cannot be inferred.
Validate the spec with scripts/validate_spec.py or cad_skill.validators.
Choose a backend: fusion first, freecad when Fusion is unavailable, and openscad for simple CSG previews.
Generate code with scripts/generate_model.py.
Save generated files under outputs/<model_name>/.
If execution is requested, run the script in the CAD tool or use the optional Computer Use plan from cad_skill.computer_use_adapter.
Report files created, assumptions, validation issues, run instructions, and known limitations.

Safety

Prefer official scripting APIs over GUI automation.
Never overwrite, delete, or move user files unless explicitly requested.
Keep generated scripts in a dedicated output directory.
Validate units, dimensions, wall thickness, backend feature support, and export requests before generation.
Treat Computer Use as optional and platform-specific.

Scripts

Generate code: python scripts/generate_model.py --spec assets/examples/mounting_bracket/example.spec.json --backend fusion --out outputs/mounting_bracket
Generate all examples: python scripts/generate_all_examples.py --backend all --overwrite
Validate only: python scripts/validate_spec.py assets/examples/phone_stand/example.spec.json --strict
Preview plan: python scripts/render_preview.py --spec assets/examples/simple_gear/example.spec.json --backend openscad
Fusion run plan: python scripts/run_fusion_script.py outputs/mounting_bracket/mounting_bracket_fusion.py

Read the full file on GitHub · 65 lines

Files

What ships with it

60 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2mo ago First seen · 65 lines · 66 tokens per session scan A 26f6cb52fc58

Subscribe to this mod's changes

cad-modeling-fusion is a skill published in the GitHub repository Foster1202/cad-modeling-fusion-skill (2 stars, last pushed 3mo ago), licensed MIT. It adds 66 tokens to every session and 1,110 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-31.

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