From Onshape Labs, the FeatureScript MCP Server: The Fastest Path to AI-Driven Design

What if you could describe a custom CAD feature in plain language and have AI turn it into a reusable engineering tool?

That’s the idea behind the FeatureScript MCP Server from Onshape Labs. By connecting AI clients such as Claude, ChatGPT, or Gemini directly to FeatureScript, engineers can create custom Onshape features using natural language instead of writing code themselves.

Results enable something more than a one-off model or a static piece of geometry. It’s a reusable custom feature that can be shared across teams and used like any other tool in the Onshape toolbar.

The FeatureScript MCP Server opens FeatureScript to large language models, allowing AI to communicate in Onshape’s native language. Instead of asking an AI to generate geometry directly, you’re asking it to create the code that defines how geometry is created.

How to Get Started with FeatureScript MCP Server

To get started with the FeatureScript MCP Server, all you need to do is complete three steps:

1. Have an Onshape account and be signed in
2. Subscribe to the Onshape Labs FeatureScript MCP through the Onshape App Store
3. Connect the MCP server to your AI client of choice using the following URL: https://fs-mcp.labs.onshape.app/mcp

What’s FeatureScript?

FeatureScript is Onshape’s built-in programming language for creating and customizing CAD features.

Not a separate add-on or macro layer, it’s the same language Onshape developers use to build the platform’s native tools. When you create a custom feature with FeatureScript, it behaves like any other Onshape feature: fully parametric, integrated into the user interface, and supported across browsers, iOS, and Android.

Onshape also makes the source code behind its native features publicly available, allowing users to learn how those features work and build their own custom tools. That openness has made FeatureScript one of Onshape’s most powerful capabilities, but until now, it has largely remained the domain of programmers.

What’s an MCP Server?

MCP stands for Model Context Protocol, an open standard that allows AI applications to interact with external systems.

If APIs are how software talks to applications, MCP is how AI talks to applications.

The FeatureScript MCP Server gives AI models access to a set of tools that allow them to work with FeatureScript inside Onshape. Rather than simply discussing a design problem, the AI can actively generate, test, and refine FeatureScript to create working custom features.

Because MCP is an open protocol, the FeatureScript MCP Server works with any compatible AI client.

How the FeatureScript MCP Server Works

The FeatureScript MCP Server is purpose-built to help engineers create FeatureScript using natural language.

This connection allows you to simply describe the feature you need. By understanding the language Onshape speaks, AI can generate FeatureScript, insert it into an Onshape document, run it, evaluate the results, identify errors, and revise the code when needed.

As AI models continue to improve, the complexity of custom features they can generate will continue to grow as well.

What the FeatureScript MCP Server Enables

For years, FeatureScript has given engineers the ability to create highly specialized tools tailored to their workflows. The challenge has been that creating those tools required programming knowledge.

The FeatureScript MCP Server helps close that gap.

Engineers already understand the parts they design, the standards they follow, and the repetitive tasks that slow them down. What many don’t have is the experience required to turn that knowledge into custom engineering tools.

Now, mechanical engineers and designers can describe the tool they need in natural language and let AI handle much of the coding process.

There are four concrete ways engineers can benefit.

Customize CAD Features & Functionality

Consider a common workflow, such as creating hydraulic ports.

The geometry may be well documented and standardized, but the modeling process can still be repetitive and time-consuming. Traditionally, automating that process required custom programming.

With the FeatureScript MCP Server, an engineer can provide the documentation, describe the intended workflow, and have AI generate a custom feature that follows those specifications. Instead of learning FeatureScript from scratch, engineers can create specialized CAD functionality tailored to their products, standards, and design processes.

Create Parts and Systems of Parts

The same approach can extend beyond individual modeling operations.

Rather than generating a single feature, engineers can create configurable parts or entire systems of related parts driven by design rules and engineering requirements. A prompt can be transformed into reusable logic that automatically generates geometry, captures design intent, and ensures consistency across product families.

Create Engineering Tools

FeatureScript is not limited to geometry creation. It can also be used to build engineering tools that automate calculations, validation checks, and repetitive design tasks.

For example, a company could transform a documented design process into a custom tool that guides users through required inputs, applies engineering rules, and generates consistent results. What previously existed as a manual workflow becomes a repeatable capability available directly inside Onshape.

Codify Existing Geometry for Robust Reuse

Organizations often have decades of proven designs embedded in existing models and engineering documentation. The FeatureScript MCP Server makes it easier to convert that knowledge into reusable custom features.

Once created, a feature becomes a reusable engineering capability that can be added to workflows just like any native Onshape command. The output isn’t a one-time model, as the phrase “text-to-CAD” suggests, but a repeatable process captured in code that can be reused whenever needed, making text-to-code-to-CAD the real, streamlined actuality.

Build Once, Share Everywhere, No Token Expense

Once a custom feature has been created, it can be shared using Onshape’s existing feature-sharing capabilities.

Teams can distribute custom tools across an organization and standardize workflows without requiring every engineer to build the same functionality independently.

The economics are also different from many AI-assisted workflows. The AI is used to generate the FeatureScript. Once the code exists, it runs like any other custom feature. Engineers can continue using it without returning to the AI each time they need the geometry.

Available Now in Onshape Labs

The FeatureScript MCP Server is being introduced through Onshape Labs, an early-access program for emerging technologies and experimental workflows.

The release represents an important step toward a future where engineers can create custom tools through conversation, while still benefiting from the editable, parametric, and reusable nature of CAD.

Want More Control? FeatureScript Co-Complete

The MCP Server isn't the only place AI is opening up FeatureScript. Onshape's Feature Studio, the built-in environment for custom feature development, has gained FeatureScript Co-Complete, a context-aware inline autocomplete that suggests the next function or snippet as you type.

The difference is how much of the build you hand off. With the MCP Server, you describe the outcome and let AI generate and refine the code. With Co-Complete, you stay at the keyboard, authoring the logic yourself while AI removes the friction of syntax lookup and boilerplate.

Neither is the beginner path or the expert path. The same engineer might prompt an AI to create a new custom feature in the morning and hand-tune FeatureScript in the afternoon. What's new is that both ends of the spectrum are now AI-assisted, so the choice is about how much control the task deserves, not what you're capable of building.

Unlocking the True Power of FeatureScript

Only Onshape combines cloud-native CAD and PDM with AI-powered customization, enabling you to build engineering capabilities tailored to your company’s products and processes.

By making FeatureScript more accessible, the FeatureScript MCP Server expands what’s possible for engineers, allowing them to create custom CAD functionality, automate engineering workflows, and capture proven design knowledge for reuse.