> Source scope: this repository contains the reusable CAD runtime, CLI, MCP tools and headless renderer. Hosted product UI and commercial manufacturing services are maintained separately. Build the reusable tools with `npm run build`; use `npm run dev` for the standalone renderer. # kernelCAD - CAD runtime for agents **kernelCAD** turns mechanical intent into editable `.kcad.ts` source, deterministic review evidence, and exportable manufacturing artifacts. The core loop is source-first: design brief -> editable `.kcad.ts` -> evaluated model -> deterministic validation -> guided revision -> export package. kernelCAD is not trying to be a browser clone of Fusion, Onshape, or SolidWorks. Replicad/OpenCASCADE are the kernel layer. kernelCAD is the agent-first workflow layer above the kernel: deterministic CAD source, feature history, diagnostics, validation, variants, and human review. ## Install ### Already in ChatGPT and Claude: no install kernelCAD runs as a connected app in **ChatGPT** (Apps SDK, with the Studio viewer and paint review inside the chat) and in **Claude / claude.ai** (custom connector). Add it from the chat settings and sign in: - ChatGPT: [connect guide](https://app.kernelcad.com/connect?client=chatgpt) or [ChatGPT → Settings → Connectors](https://chatgpt.com/#settings/Connectors) - Claude: [connect guide](https://app.kernelcad.com/connect?client=claude) or [claude.ai → Settings → Connectors](https://claude.ai/settings/connectors), URL `https://mcp.kernelcad.com/mcp` **One account everywhere.** The coding-agent plugins below use the same hosted server (`https://mcp.kernelcad.com/mcp`) and the same kernelCAD sign-in. A model saved from Claude Code, Codex, Cursor, Gemini or Grok opens at the same Studio share link (`/p/`) you see in ChatGPT or Claude. Sign in with the same account in each client. Ask your agent: **“look at kernelcad.com and install the mcp”**. [Agent-readable installation instructions](https://kernelcad.com/llms.txt) cover hosted setup, local CLI setup, and connection verification. ### Local CLI: one line For Node.js users (Node.js 22.12 or newer): ```bash npm install --global kernelcad ``` For a self-contained install that includes Node.js, Linux and macOS users can run: ```bash curl -fsSL https://kernelcad.com/install.sh | sh ``` On Windows PowerShell, run: ```powershell irm https://kernelcad.com/install.ps1 | iex ``` The direct installers download a platform archive, verify its SHA-256 checksum, and install it under the user's home directory. Pin a release with `KERNELCAD_VERSION=vX.Y.Z` on Linux/macOS or `$env:KERNELCAD_VERSION='vX.Y.Z'` in PowerShell. Builds are available for Linux x64/ARM64, macOS Intel/Apple Silicon, and Windows x64. Direct installs do not require a separately installed Node.js. ### Coding agents: one command One command connects your agent to the hosted kernelCAD MCP server (`https://mcp.kernelcad.com/mcp`) and adds the kernelCAD skills. Nothing runs locally and no OpenCASCADE install is needed. Anonymous use works; sign in through your client's OAuth prompt for account features. | Agent | One-liner | |---|---| | Claude Code | `claude plugin install kernelcad --marketplace w1ne/kernelCAD-web` | | Codex | `codex plugin marketplace add w1ne/kernelCAD-web && codex plugin add kernelcad@kernelcad` | | Cursor | [Add kernelCAD MCP to Cursor](cursor://anysphere.cursor-deeplink/mcp/install?name=kernelcad&config=eyJ1cmwiOiJodHRwczovL21jcC5rZXJuZWxjYWQuY29tL21jcCJ9) (MCP only) | | Gemini CLI | `gemini extensions install https://github.com/w1ne/kernelCAD-web --consent --auto-update` | | Grok Build | `grok plugin marketplace add w1ne/kernelCAD-web && grok plugin install kernelcad --trust` | | VS Code / Copilot | `code --add-mcp '{"name":"kernelcad","type":"http","url":"https://mcp.kernelcad.com/mcp"}'` | | Skills only (any agent) | `npx skills add w1ne/kernelCAD-web` | Inside Claude Code you can also type `/plugin marketplace add w1ne/kernelCAD-web` then `/plugin install kernelcad@kernelcad`. Restart the app after installing. Claude Desktop, ChatGPT, Windsurf, Cline, Zed, Continue, update, uninstall and the Cursor skills install are in [docs/usage/agent-plugin-install.md](docs/usage/agent-plugin-install.md). ## Showcase Each model below started from the plain-language prompt shown. An AI agent wrote it through kernelCAD's own authoring loop (CLI / MCP): it wrote `.kcad.ts` source, ran `evaluate`, rendered the seven-view inspection sheet, read the renders, fixed what was wrong, and repeated. None of these is a one-shot generation. Each folder in [`showcase/`](showcase/) holds the parametric source, the turntable GIF (`kernelcad animate --turntable`, publish look), and a short note on what to look at and which checks were run. | Model | Prompt | Params | Preview | |---|---|---|---| | [Twisted hex vase](showcase/twisted-hex-vase/) | Hollow shell ~150 mm tall, tapers 70 → 50 mm, hex section twisting 120°, 2 mm wall, closed bottom | `height` `baseDia` `mouthDia` `twistDeg` `wall` | Twisted hex vase turntable

| | [Knurled control knob](showcase/knurled-knob/) | Ø40 × 22 mm, diamond-knurled grip, raised pointer, 6 mm D-shaft bore, M3 set-screw hole | `diameter` `height` `knurlDepth` `knurlTwistDeg` `knurlTeeth` `shaftDia` `dFlatDepth` `boreDepth` `skirtHeight` | Knurled knob turntable

| | [Honeycomb bracket](showcase/honeycomb-bracket/) | Filleted L-bracket with a generative hex lattice | `thickness` `innerFillet` `cellSize` `web` | Honeycomb bracket turntable

| | [NACA 2412 wing](showcase/naca-2412-wing/) | True airfoil from the NACA equations, tapered loft | `semiSpan` `rootChord` `tipChord` `leSweep` `dihedralRise` `washoutDeg` | NACA 2412 wing turntable

| | [Centrifugal impeller](showcase/centrifugal-impeller/) | 7 swept backward-curved blades | `bladeCount` `wrapDeg` `backplateThickness` `boreDia` `keyWidth` | Centrifugal impeller turntable

| | [9-cylinder radial engine](showcase/radial-engine/) | Round crankcase, nine finned cylinders in a star, domed heads, prop hub | `cylinderCount` `barrelLength` | Radial engine turntable

| Some checks go past the picture: - **Mechanisms that are checked, not just drawn.** The planetary stage and the bevel drive are assemblies with revolute mates, gear ratios coupled from the tooth counts, and declared gear-pair transmissions. kernelCAD's mechanism-truth check (`evaluate_script` → `mechanism: "real"`) turns each mechanism through its limits with the couplings applied and looks for overlapping teeth. `kernelcad validate --include-interference` reports both assemblies clean. - **Manufacturing evidence.** The honeycomb bracket declares an FDM print gate. `kernelcad dfm` passes it (thinnest wall 2.0 mm, no unsupported overhang), and `kernelcad export step` writes a B-rep whose holes read back with `kernelcad inspect step`. ## Philosophy 1. **Agent-First**: The primary interface is `.kcad.ts`, CLI, and MCP. The UI reviews and steers generated designs. 2. **Editable Source**: Geometry is deterministic source code with explicit feature history, params, assemblies, and diagnostics. 3. **Validation-Centered**: Useful CAD output needs deterministic review for constraints, hardware fit, clearances, and exportability. 4. **Workflow Over Primitives**: Product progress is measured by intent-level workflows, not by copying every traditional CAD button. ## Reference-parts accuracy The headless OCCT gate checks 27 native `.kcad.ts` reference parts against analytic or recorded OCCT volume, surface-area, and bounding-box values. The current headline is 25/27 reference parts match; the expected-pass gate is 25/25, with two documented known failures and their reasons listed in the scorecard. See the [reference-parts scorecard](docs/reference-parts-scorecard.md) and its [local validation demo](docs/demos/reference-parts-scorecard/README.md). ## Agent workflow For agents and contributors, `.kcad.ts` source is the design source of truth. Rendered PNG/MP4 files, STEP/STL exports, score JSON, and capture-run metadata are generated evidence or deliverables. Prompt briefs, source files, and provenance metadata remain source. Change source first, regenerate explicit targets, and avoid broad artifact refreshes unless you are intentionally rebuilding a demo or release bundle. Use deterministic checks before visual judgment: ```bash kernelcad evaluate model.kcad.ts # then run review_cad from an MCP client connected through `kernelcad mcp` kernelcad export step model.kcad.ts -o model.step kernelcad export stl model.kcad.ts -o model.stl ``` Translate an assembly exported from SolidWorks or another CAD application as STEP into a KernelCAD project: ```bash kernelcad import-step robot.step --out robot-kcad kernelcad evaluate robot-kcad/robot.kcad.ts ``` The bundle contains a `.kcad.ts` root assembly, `manifest.json` with the source product paths, units, placements, colors, and geometry measurements, and exact native OCCT BREP assets content-addressed by geometry. Byte-identical product definitions share an asset. The original STEP assembly hierarchy is recorded in the manifest; the current KernelCAD scene is flattened into independently placeable occurrences. Local STEP `DOCUMENT_FILE` dependencies are read recursively, included in the import provenance hashes, and must stay inside the input directory. Component colors are preserved; per-face color mapping is not part of this import. It does not infer mates, joints, motion, feature history, or read native SolidWorks/Parasolid data. See the [retained import demo, bundle, and verification evidence](docs/demos/step-to-kernelcad/README.md). When a rendered artifact is produced, inspect the image/video itself and report what is visible: proportions, interfaces, floating geometry, occlusion, camera framing, and whether required features are legible. Passing tests are not a substitute for visual evidence. When visual evidence matters, keep a deterministic inspection bundle: ```bash kernelcad render inspect model.kcad.ts model.inspect ``` The v1 bundle writes a manifest and canonical RGB views. It can also emit machine-readable `mask`, `depth`, and `normals` channels: ```bash kernelcad render inspect model.kcad.ts model.inspect --channels rgb,mask,depth,normals ``` Use `--focus ` or `--hide ` when a specific feature id or assembly part needs isolated review. Keep richer channels in the same manifest packet; do not replace the canonical RGB views. For real hardware, prefer catalog/vendor geometry via `lib.fromSTEP(...)` instead of fake placeholder boxes or cylinders. This keeps mounts, clearances, and mechanism checks tied to physical components. ## Features - **Headless Core**: Run CAD operations in Node.js or Web Workers without a DOM. - **Agent API**: kernelCAD APIs for params, assemblies, NURBS, SDF bodies, sheet metal workflows, introspection, and feedback loops. - **Review Cockpit**: Browser-based 3D preview for inspecting generated designs and validation results. - **Standard Exports**: STEP/STL generation. - **Robust Kernel**: Built on OpenCASCADE, with Replicad kept as a kernel implementation detail where it is still used. ## Get Started ```bash npm install --global kernelcad ``` The npm package requires Node.js 22.12 or newer. For a self-contained install, use the platform installer above. Drop this in `bracket.kcad.ts`: ```typescript const w = param('Width', 60, { unit: 'mm' }); const h = param('Height', 40, { unit: 'mm' }); const t = param('Thickness', 5, { unit: 'mm' }); const base = box(w, h, t); const hole = cylinder(t + 2, 4).translate(w / 2, h / 2, -1); return base.subtract(hole).fillet(1); ``` Run it: ```bash kernelcad evaluate bracket.kcad.ts kernelcad export stl bracket.kcad.ts -o bracket.stl ``` That's it. For agents: `kernelcad mcp` runs an MCP server with dynamic model introspection tools. Object tool responses include `structuredContent` alongside the serialized JSON text so MCP clients can validate advertised output schemas. See `SKILL.md` (bundled with the install) for the full API surface and authoring guide. ## Use with Claude Desktop kernelCAD runs as an MCP server, so Claude Desktop can drive it locally. After the one-line install, add an entry to your Claude Desktop config file: - **macOS:** `~/Library/Application Support/Claude/claude_desktop_config.json` - **Windows:** `%APPDATA%\Claude\claude_desktop_config.json` - **Linux:** `~/.config/Claude/claude_desktop_config.json` ```json { "mcpServers": { "kernelcad": { "command": "kernelcad", "args": ["mcp"] } } } ``` Restart Claude Desktop. The kernelCAD MCP tools (`review_cad`, model introspection, export helpers, etc.) appear in the tools list. The first full local `evaluate_script` build returns `viewerUrl`. Open it in Studio once: later full builds and source-edit tool calls replace the source, history, and geometry behind that same session link. The viewer is served on `127.0.0.1` by the MCP process and lasts until that process closes; it is not a public share link. Dry runs leave it unchanged. A build failure keeps the last built model visible; a successfully built model with DFM failures remains viewable. Build diagnostics shown there are not a full CAD/physics review. Published packages include the Studio bundle. When running MCP from a checkout, run `npm run build:mcp-viewer` first. If the bundle cannot be served, the build result includes `viewerError` separately from its CAD diagnostics. Hosted MCP and `--cloud` continue to use the gateway's Studio/project URLs. [Local viewer workflow](docs/demos/mcp-viewer-link/README.md). For hosted workflows, sign in at [the existing connection guide](https://app.kernelcad.com/connect?client=claude). It gives the current connector and OAuth steps for your client. The hosted tool set depends on authentication, your selected profile, and server-native tools; use the connected server's discovery rather than assuming the local list. The local installer is available. Preview the config change before applying it: ```bash kernelcad install --claude-desktop --dry-run kernelcad install --claude-desktop ``` Other hosted setup guides: [ChatGPT](https://app.kernelcad.com/connect?client=chatgpt), [Claude](https://app.kernelcad.com/connect?client=claude), [Claude Code](https://app.kernelcad.com/connect?client=claude-code), [Codex](https://app.kernelcad.com/connect?client=codex), [Gemini CLI](https://app.kernelcad.com/connect?client=gemini), [Grok Build](https://app.kernelcad.com/connect?client=grok), [Cursor](https://app.kernelcad.com/connect?client=cursor), and [VS Code](https://app.kernelcad.com/connect?client=vscode). Browse the generated [local MCP tool reference](https://kernelcad.com/docs/mcp-tools) for complete input/output schemas and behavior annotations, or search the [design guide](https://kernelcad.com/docs/design-guide) for existing recipes and cited, dated manufacturing catalog snapshots. For local Studio, [`get_selection` and `set_selection`](docs/guide/shared-selection.md) share face/edge picks with your MCP agent. Open the same script in Studio and use its session token; picks expire on model rebuild. For opt-in kernel selection and fallback diagnostics, see the [experimental guarded SMLib kernel guide](docs/smlib-kernel.md) and its [workflow demo bundle](docs/demos/smlib-guarded/README.md). ## Contributing Web app + dev workflow (clone the repo, `npm install`, `npm run dev`) for contributors who want to hack on the kernel or the visual debugger: ```bash git clone https://github.com/w1ne/kernelCAD-web.git cd kernelCAD-web npm install npm run dev # web visual debugger at localhost:5173 npm run build:cli # build the CLI bundle into dist/cli/ npm run test # full vitest suite npm run qc # quick quality gate (lint + typecheck + tests) ``` ## Attribution Exported files name kernelCAD in their metadata field (STEP `FILE_NAME`, GLB `asset.generator`, the STL header, a DXF or XML comment), and public viewer pages show a small "Made with kernelCAD" link. Self-hosters and forks change this in `src/shared/links/attribution.ts`. See [ATTRIBUTION.md](ATTRIBUTION.md). ## License MIT — see [LICENSE](LICENSE). The kernelCAD name is covered by the [trademark policy](TRADEMARKS.md).