A new open-source TypeScript library from Vercel, UI SDK, treats focus, selection, popups and the rest of ordinary interface work as reusable behaviours that an agent can put together into a component. You’ll find the source at github.com/vercel-labs/ui and the documentation at ui-sdk.dev. The first npm packages, version 0.1.0-beta.1, are under the Apache-2.0 licence, and because Vercel has listed the project as a public beta, the APIs can still change before general availability.
Introducing the UI SDK.
November 12, 2026
In a post published alongside the announcement, shadcn, who built the library with Shu Ding, explained the thinking. “Agents are becoming both the builders and the users of interfaces. So we asked ourselves: where should the abstraction live?” A Select, he wrote, is a popup, selection logic, keyboard navigation and focus management, and those same behaviours are useful in lots of other components. “Give agents the pieces to generate the interface you need, right when you need it. Even interfaces we haven’t thought of yet.”
The official site uses that Select as the example. Instead of handing an agent a finished Select, you give it createPopup, createSelection and createTypeahead. From those pieces it can also build an autocomplete, a combobox, or a component that isn’t in the catalogue yet. Behaviours live in @ui-sdk/core, which the README describes as the home of keyboard navigation, focus, selection, dismissal, popups, drag and drop and the ARIA they need. Official docs say the team has built more than 50 of them.
Today we’re introducing UI SDK.
November 12, 2026
Agents are becoming both the builders and the users of interfaces. So we asked ourselves: where should the abstraction live?
Take a Select. There’s a popup, selection logic, keyboard navigation and focus management. Those same behaviors are useful in lots of other components.
Starter components
You define a primitive once in the core package, then render the same parts with createParts in React, Vue, Svelte, Solid or Web Components. The React adapter needs React 19 or newer. The same behaviours also ship as a starter component library: the React docs list 55 unstyled components, from Accordion to Waterfall, with matching parts in the other four adapters. You bring the styles. A typical install is npm install @ui-sdk/react @ui-sdk/core, and Vercel tells you to add the UI SDK skill with npx skills add vercel-labs/ui --skill ui-sdk.
Developers who already use Vercel’s AI SDK may notice the similar name. UI SDK is a separate library. AI SDK UI is the older set of React hooks such as useChat, and this release does not replace it.
How agents use what they build
The docs treat agents as builders and as users. On the build side, each package includes Markdown docs for the installed version, plus a testing kit for keyboard behaviour, focus and ARIA. On the use side, you can call createAgent before the page renders, then ask the agent to read component state and call actions such as an input’s setValue, subject to an allow callback you provide. Change callbacks receive source: "agent" and can cancel a change. If you want a browser’s own agent to use those tools, the docs say to register them with WebMCP by calling registerTools. Speaking about the release, Vercel CTO Malte Ubl described agentic composition and agentic use as “first-class” features, and said every UI SDK app exposes a WebMCP.
Vercel’s homepage says agents that “read the page and work the controls directly, without screenshots” are “more than twice as fast, at less than half the cost.” The numbers sitting behind that claim are in the agents documentation. In a project-settings task, agents renamed a project, updated members and notification settings, then saved. One used browser tools on a page built with another component library; the other used the agent bridge on the same screen built with UI SDK. Both used Sonnet through Claude Code, with the same task and system prompt, plus instructions for their available tools. Every run completed the task. The figures below are medians from three runs on each side. Time and cost are what Claude Code reported, and “text read” counts characters returned by the tools.
| Browser tools | UI SDK and the agent bridge | |
|---|---|---|
| Tool calls | 16 | 5 |
| Text read | 39.8k | 6.8k |
| Time | 41 s | 16 s |
| Cost | $0.073 | $0.032 |
On those runs, time fell by 61% and cost by 56%. Vercel did not name the other component library in the comparison, and it hasn’t published a larger public evaluation.
Rauch, in his own post, called UI SDK “the x86 instruction set for agents to build new UI components spontaneously.” He wrote that high-level, rigid, single-framework abstractions are “like kryptonite” for that kind of generation, and that packaged behaviours can keep accessibility, performance and cohesion “with absolutely zero limitations and tradeoffs for what UIs we can generate.” Tom Occhino, who works on engineering, product and design at Vercel, wrote: “I haven’t had this feeling about a project since React. It doesn’t feel like @shadcn invented something, it feels like he discovered something.”
What happens to frameworks in the agents era? to component libraries? to @shadcn?
November 12, 2026
The answer is: we need to drill deeper. Delete the part, optimize, accelerate, automate.
UI SDK is like the x86 instruction set for agents to build new UI components spontaneously.
shadcn has said the team has built more agentic features into UI SDK and will show them in the coming days. The introducing post is dated 12 November 2026, and the project remains under Vercel’s public beta terms.
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