What is SolidCraft?
SolidCraft, from Tangency Labs, is a free parametric 3D CAD application written in Rust. You draw constrained sketches, turn them into solids with extrude, revolve, sweep, loft, fillet, chamfer, shell and similar features on an editable timeline, and change a parameter to rebuild the part. It also handles assemblies with joints and motion studies, sheet metal, and STEP, IGES, 3MF, STL, OBJ and glTF files, with URDF export. Builds ship for Windows, macOS and Linux, and a browser version runs without an install.
The same command set drives the desktop app, the browser app, a headless CLI and an MCP server. `solidcraft-cli mcp` speaks MCP over stdio with 22 tools; headless it runs its own design session, and bridged it drives the running app so you can watch the agent model. Five agent skills ship alongside it.
The repository opened on 7 October 2026 and had about 16,100 GitHub stars and 2,200 forks five weeks later. Code is licensed MIT or Apache-2.0; the name, logo, icons and themes sit under a separate brand licence. v0.41.0 came out on 13 November 2026.
How to install SolidCraft
claude mcp add solidcraft -- solidcraft-cli mcpIs SolidCraft worth it?
Most CAD servers for MCP bolt an agent onto a program designed for a mouse. SolidCraft was built the other way round: every toolbar action is an engine command, and the 22 MCP tools call those same commands. An agent lists the catalogue with list_commands, reads a command's JSON Schema with describe_command, then runs steps in a batch that stops and undoes itself at the first error. The expect argument lets it state the volume, body count or bounding box a stage should produce, and the server measures the result and flags a mismatch as an error. That is the right design for a model that cannot see what it built.
The defaults are careful. The desktop app's control channel is off on a new install; when switched on it listens on 127.0.0.1:27878 and every connection must present a token made fresh for that launch. File tools reach only the open design's folder inside your home directory, never hidden folders such as ~/.ssh or ~/.config, unless you add folders with --allow-path; --allow-any-path removes the limit. The privacy policy says the desktop app has no telemetry or accounts and makes one outbound call, a daily update check to GitHub, which can be switched off.
The catch: SolidCraft is very young and moving fast. The repo is five weeks old, holds about 6,000 open issues, and shipped v0.40.1 and v0.41.0 on consecutive days, the second with a new design file format. The project's own claim is modest: early but usable for simple parts, with 75 of 76 public reference parts matching analytic or FreeCAD volumes, areas and centres of mass. The geometry kernel, SolidCore, is a Rust port of NVIDIA's SMLib, which is less proven than the Parasolid or ACIS kernels behind commercial CAD.
Our take: for brackets, enclosures and printable parts, SolidCraft gives an agent a better workbench than writing OpenSCAD code, because it can check its own geometry and you can open the result in a real feature timeline. For anything you would send to a machine shop, keep a human and a mature CAD package in the loop.
Where it earns its place
A hobbyist with a 3D printer
Get a case for a single-board computer with standoffs, vents and port cut-outs
Ask the agent to build the case from the board's dimensions in a few batch calls, with expect checks on the bounding box, then export STL or 3MF. Free; resize later by changing one parameter.
A two-person robotics start-up
Keep a family of mounting brackets in sync with changing motor sizes
Drive parameters through set_parameter or check_parameters, measure each variant and export STEP for the supplier. Saves redrawing each variant by hand; check fits in an assembly before ordering parts.
A university robotics lab
Produce simulation models from CAD parts
Build or import parts, set joints in an assembly and export URDF or GLB for the simulator. No licence cost per seat, which matters for a class of 30.
Before you commit
- Setup
- Install the Windows, macOS or Linux build, then run solidcraft-cli mcp setup or Help > Connect AI assistants to register the server with installed clients. For Claude Code: claude mcp add solidcraft -- solidcraft-cli mcp. Turn on Preferences > Assistant to let agents drive the open window.
- Integrations
- 22 MCP tools over stdio, five agent skills, JSON command scripts through solidcraft-cli run, a browser command API and sandboxed WebAssembly plugins. Imports and exports STEP, IGES, 3MF, STL, OBJ and glTF; exports URDF.
- Data and privacy
- Designs stay on your machine or in browser storage. The privacy policy states no telemetry, no accounts and local-only crash reports; the only automatic call is an update check to GitHub. The optional desktop agent chat sends prompts and design data to the endpoint you choose, such as Ollama or LM Studio, with API keys in the system keychain.
- Cost at scale
- Free for any number of seats. Your cost is the model behind the agent.
- Limits
- Beta software: about 6,000 open issues, a new file format in v0.41.0, and plugins marked experimental. Bridged screenshots need the server and the app on the same machine; plugin runs have a 30-second deadline.
What’s good
- Agent and user share one command set
- expect checks volume, bodies and bounding box
- File access scoped to the design folder by default
- No telemetry; MIT or Apache-2.0
What’s not
- Five weeks old with about 6,000 open issues
- Design file format still changing between releases
- Young kernel, tested on 76 reference parts
- Plugins are experimental
Best for
Makers and small hardware teams who want an agent to model and revise simple mechanical parts in an open, scriptable CAD program.
SolidCraft alternatives
SolidCraft: common questions
- Is SolidCraft worth it?
- SolidCraft is the first CAD program where an agent works through the same command set as a person, with a verify step built in, but it is a five-week-old beta and should be treated as one. We rate it 4.0 out of 5.
- How much does SolidCraft cost?
- Free and open source (MIT or Apache-2.0). No paid tiers are published; agent chat uses whatever model endpoint you configure.
- What are the downsides of SolidCraft?
- Five weeks old with about 6,000 open issues; design file format still changing between releases; young kernel, tested on 76 reference parts; plugins are experimental.
- Who is SolidCraft best for?
- Makers and small hardware teams who want an agent to model and revise simple mechanical parts in an open, scriptable CAD program.
- How much does SolidCraft cost for a team or in production?
- Free for any number of seats. Your cost is the model behind the agent.
- Is SolidCraft safe for company data?
- Designs stay on your machine or in browser storage. The privacy policy states no telemetry, no accounts and local-only crash reports; the only automatic call is an update check to GitHub. The optional desktop agent chat sends prompts and design data to the endpoint you choose, such as Ollama or LM Studio, with API keys in the system keychain.
- What are the best SolidCraft alternatives?
- The closest alternatives we have reviewed are OpenSCAD MCP and MCP for Blender.
Answers checked Nov 13, 2026.
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