Candor UI and a free kit

Three free kits a team might start from: AI Elements, assistant-ui and CopilotKit. Each section says what that kit’s own pages name that it ships, with the address we read it at. We read them on 9 November 2026; they change, so check them.

This is a list of what each names, not a ranking. A feature a kit’s page doesn’t list is not evidence that it is missing, and we haven’t tested any of them. Where a free kit already does what you need, use it.

AI Elements (Vercel)

A component library and custom registry built on shadcn/ui for AI-native applications.

Licence: Apache-2.0 (the repository's LICENSE file); the README doesn't state it.

What its pages name

49 components, counted in its docs: 19 for chatbots (among them Confirmation, Plan, Queue, Checkpoint, Reasoning, Sources, Tool and Prompt Input), 15 for code (among them Terminal, Test Results, Stack Trace, Sandbox and File Tree), 6 for voice, 7 for workflow canvases and 2 utilities
Three examples: a chatbot, an IDE and a workflow

Its README and a banner on its docs site say the project will be deprecated at the end of November 2026 and replaced by AI Elements from shadcn/ui, and that new projects should use the shadcn/ui version once it's available.

Read at:elements.ai-sdk.dev github.com/vercel/ai-elements its LICENSE file ui.shadcn.com/docs/ai-elements

assistant-ui

Composable primitives for chat interfaces, with a styled starter the CLI copies into your project.

Licence: MIT.

What its pages name

Thread, Message, Composer, ThreadList and ActionBar, and more
Tool calls and JSON rendered as React components, inline human approvals, and frontend actions exposed to the model
Integrations it lists: the Vercel AI SDK, LangGraph and LangChain, AG-UI and A2A, Google ADK and OpenCode, and a custom data-stream backend

It also offers an optional Assistant Cloud for managed thread history, telemetry and file storage.

Read at:github.com/assistant-ui/assistant-ui

CopilotKit

An open-source stack for putting agents in front of users: chat, generative UI, shared state and human-in-the-loop, in React, Angular, Vue, React Native, Slack and Microsoft Teams.

Licence: The source in the repository is MIT.

What its pages name

Prebuilt chat that can be customised with slots or replaced with a headless UI
Generative UI in three kinds: controlled, declarative (A2UI) and open-ended (MCP Apps)
Shared agent and UI state, frontend tools, human-in-the-loop pauses, AG-UI streams, voice and WebMCP, and an inspector (a localhost overlay that shows threads, agents and learning)

A production layer, CopilotKit Intelligence, is cloud-hosted or self-hosted and has a free Developer plan; its README lists Continual Learning, AG-UI Streams, User Memories, Product Analytics, Channels and a self-hosted option under it.

Read at:github.com/CopilotKit/CopilotKit

Candor UI

A shadcn/ui registry for AI agents that do real work: chat, plans, approvals, diffs, runs and evals, with adapters for the Vercel AI SDK, the Claude Agent SDK and AG-UI.

Licence: MIT for the 74 free items (52 agent components and hooks, 13 primitives and the theme). Pro, Premium and Team are paid, one-time, under the Candor UI licence: Pro $149, Premium $249, Team $999.

What the paid tiers add is in the pricing; a free kit’s own additions are in its section above. Candor’s claims, and where to check each:

Every control that can't be used says why, and nothing is pre-selected in a decision.The Typical / Honest switches show the same moment both ways. Check it
Model output is text, never HTML or a clickable link; unknown stays unknown; destructive actions say what can and can't be undone.Each rule is on the principles page, and the CLI's lint checks an app against the first two (model output rendered as HTML, an estimate shown as measured). It doesn't check the undo rule. Check it
Every component runs axe in the test suite, and every text pair is contrast-measured in three themes.The accessibility page says what is checked and what isn't. Check it
The free tier is MIT and public, regenerated from a private source on each release.Read the source and the release notes. Check it