Is the Forgecad skill free?

Yes. The skill itself is free from KoStard/forgecad-public-kit. SkillProof publishes the install command and an independent test verdict at no cost.

What is the Forgecad SkillProof Score?

9.6/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 5/5.

How do I install Forgecad?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use Forgecad with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

Forgecad

Parametric CAD in .forge.js files, with connector-based placement and forgecad CLI checks

by KoStard · KoStard/forgecad-public-kit

Works with setup

Install — copy the command Download source ↗

Test report

Verdict: Works with setup
Score: 9.6/10
Tested: Jul 21, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 20430cf

In a temp HOME I ran `npm install -g forgecad` (0.13.0) and confirmed `forgecad run` works with no login, then built the same two-part desk cable clip twice. The baseline (no skill docs) crashed on `rotate(90,0,0)`, and after fixing from the error message it ran but rendered a full ring floating off the plate edge — scene bbox 60x45x18 mm, min [-30,-30,-3], i.e. 15 mm of overhang past a 30 mm-deep plate. The skill run, after loading the prescribed core/coordinate/positioning docs, used `pointAlong` + `connector.male/female` + `matchTo` and `verify.connectorDistance`, giving bbox 60x30x15 mm, min [-30,-15,0], `✓ Verifications: 1 pass, 0 fail`, and a render showing the arch correctly seated on the plate top between both bolt holes. All 5 spot-checked doc paths returned HTTP 200; no curl|sh, base64 blobs, or injection text anywhere in the skill tree; the only real friction is the mandatory global npm CLI and the unsubstituted {{SKILL_DIR}} placeholder when installing by git clone.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 9/10
Docs & honesty 5/5

What Forgecad does

Guides authoring, editing, and debugging ForgeCAD parametric models written as .forge.js JavaScript files, routing the agent to bundled API docs for primitives, sketches, assemblies, sheet metal, SDF, export, and CLI usage. Triggers when building or modifying ForgeCAD geometry, positioning parts that must mate, structuring multi-file ForgeCAD projects, or running forgecad run/render/inspect/export. Requires the separately installed ForgeCAD CLI (npm install -g forgecad).

How to install Forgecad

rm -rf /tmp/forgecad-src ~/.claude/skills/forgecad
git clone --depth 1 https://github.com/KoStard/forgecad-public-kit.git /tmp/forgecad-src
mkdir -p ~/.claude/skills
cp -R /tmp/forgecad-src/skills/forgecad ~/.claude/skills/forgecad
sed -i '' "s|{{SKILL_DIR}}|$HOME/.claude/skills/forgecad|g" ~/.claude/skills/forgecad/SKILL.md 2>/dev/null || sed -i "s|{{SKILL_DIR}}|$HOME/.claude/skills/forgecad|g" ~/.claude/skills/forgecad/SKILL.md
# The sed line is required: SKILL.md ships with a literal {{SKILL_DIR}} placeholder in every doc path.
# Required external tool (the skill is inert without it): npm install -g forgecad
# Verified working offline with no account: forgecad run <model.forge.js>, forgecad render 3d, forgecad inspect physical gaps.
# Hosted features (forgecad login, project clone/push, studio project sync) need a ForgeCAD account.
# Vendor alternative that also installs 10 companion workflow skills into ~/.agents/skills: forgecad skill install
# (use `forgecad skill install --core-only` for just this skill; it substitutes {{SKILL_DIR}} itself).

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger Forgecad

/forgecad Parametric CAD in .forge.js files, with connector-based placement and forgecad CLI checks

It also activates on plain-language prompts like these:

Create a ForgeCAD assembly from this SVG import
Debug why this .forge.js script fails to render
Structure this ForgeCAD project into multiple files

Frequently asked questions

Is the Forgecad skill free?: Yes. The skill itself is free from KoStard/forgecad-public-kit. SkillProof publishes the install command and an independent test verdict at no cost.
Does Forgecad work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 21, 2026. Verdict: Works with setup. In a temp HOME I ran `npm install -g forgecad` (0.13.0) and confirmed `forgecad run` works with no login, then built the same two-part desk cable clip twice. The baseline (no skill docs) crashed on `rotate(90,0,0)`, and after fixing from the error message it ran but rendered a full ring floating off the plate edge — scene bbox 60x45x18 mm, min [-30,-30,-3], i.e. 15 mm of overhang past a 30 mm-deep plate. The skill run, after loading the prescribed core/coordinate/positioning docs, used `pointAlong` + `connector.male/female` + `matchTo` and `verify.connectorDistance`, giving bbox 60x30x15 mm, min [-30,-15,0], `✓ Verifications: 1 pass, 0 fail`, and a render showing the arch correctly seated on the plate top between both bolt holes. All 5 spot-checked doc paths returned HTTP 200; no curl|sh, base64 blobs, or injection text anywhere in the skill tree; the only real friction is the mandatory global npm CLI and the unsubstituted {{SKILL_DIR}} placeholder when installing by git clone.
What is the Forgecad SkillProof Score?: 9.6/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 5/5.
How do I install Forgecad?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use Forgecad with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.