Zoo Design Studio
Mechanical CAD where parts are text. KCL source files that live in git, plus Zookeeper, an agent that writes and edits parametric models from prompts, images or sketches.
Overview
Zoo, formerly KittyCAD, built a mechanical CAD stack from the ground up instead of licensing Parasolid or ACIS. The unit of work is KCL, KittyCAD Language, a text format where a part is code with named dimensions, formulas and reusable functions. Design Studio is the application on top, hybrid in the sense that the viewport and the source are two views of one model. Version 1 shipped in May 2025.
Zookeeper arrived with v1.1 in January 2026 and is the agent layer, built the way coding agents are built, with strict context management and tool calls into the CAD API. It takes prompts, images and sketches and produces KCL. Because the output is readable code rather than a mystery solid, correcting the agent is tractable in a way that repairing generative mesh output never is. There is also a Text-to-CAD API for use outside the app, billed per second at around $0.0083.
Pricing is cheap by MCAD standards: a free download, 20 minutes of monthly agent reasoning at no cost, $20 a month for roughly 400 minutes, $99 for unlimited reasoning inside Design Studio. The real cost is architectural. The geometry engine is hosted, the desktop client is effectively a video stream over WebSockets and the MIT licence on the front-end repository does not change that. For a hardware team used to running the toolchain on its own machines, that is the question to settle before committing a product line.
Key Features
- ✓ KCL, a text modelling language where parts and assemblies are plain .kcl files you can diff, review and branch
- ✓ Zookeeper, an agent that builds and edits parametric models from prompts, reference images or sketches, with tool calls into the CAD kernel
- ✓ Hybrid editing where dragging a face in the viewport rewrites the KCL source, and editing the source updates the model
- ✓ Cloud geometry engine streamed to the client over WebSockets, so kernel work does not run on your laptop
- ✓ REST and WebSocket Design API for programmatic modelling, with Text-to-CAD available as a standalone endpoint
- ✓ Desktop builds for Mac, Windows and Linux, with the front-end app published under MIT on GitHub
Where it holds
- • Putting CAD under version control genuinely works when the model is text, and that is a real gap in SolidWorks and Fusion workflows
- • The free tier is usable for evaluation rather than a teaser, and the desktop app itself costs nothing
- • When Zookeeper gets something wrong the output is KCL you can read and fix by hand, unlike a bad mesh from a generative 3D tool
- • Built from scratch rather than wrapped around a licensed kernel, so the code path from language to geometry is coherent
Where it breaks
- • The geometry engine runs on Zoo's servers and streams video frames back. No offline modelling, and your workday depends on someone else's uptime.
- • Feature coverage sits far behind SolidWorks, NX or Fusion. Sheet metal, complex surfacing and large assembly performance are where it runs out.
- • Zookeeper handles simple parts well and gets unreliable on constraint-heavy geometry, so treat generated models as a first draft
- • Small vendor, young ecosystem and thin supplier interoperability. Moving a real product line onto it in 2026 is a bet, not a migration.
My Take
Mechanical CAD has resisted version control for thirty years, mostly because the file formats are opaque binaries. KCL is the interesting answer: models are text, git diff works and code review of a bracket becomes an ordinary thing to ask for. Zookeeper, added with the v1.1 release in January 2026, does well on simple prompted parts and loses the thread on awkward constraints, which is about what you would expect from an agent writing a modelling language. The blocker for production is architectural, since the kernel is cloud-only and streams frames to your machine, so an outage at Zoo means nobody models that afternoon.
Quick Info
- Pricing:
- freemium
- Openness:
- Proprietary
- Starting at:
- Design Studio is a free download for Mac, Windows and Linux, with a browser build at app.zoo.dev. The free tier includes 20 minutes of Zookeeper reasoning per month plus $10 of API credit. Plus is $20 per month for roughly 400 minutes of agent reasoning. Pro is $99 per month for unlimited reasoning inside Design Studio. API and Text-to-CAD calls made outside the app bill per second at about $0.0083, roughly $0.50 a minute. Credits reset on the first of the month and do not roll over.
- Added:
- Aug 2026
- Updated:
- Aug 2026
Use Cases
Judge it on your own work
The notes above say where Zoo Design Studio holds and where it breaks. The fastest check is your own workload.
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