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Fragments scans this page as it loads. The early-access form ships with a raw color, raw typography, and a raw button element; each finding is named in plain words, conforms to the contract, and the page passes with zero findings.

Govern the user interfaces your agents ship.

Invite-only for now — one email when your spot opens.

The Overview page of an example workspace: no open findings, no pull requests needing attention.

You told your agent to build UI.It didn’t build yours.

It ignored your design system — again. One rogue hex at a time, your brand’s identity slips away.

Fragments closes the loop. Your components become the contract, every agent session opens with it, every write is checked as it lands, and the same contract is required to merge.

Writesettings/NotificationsForm.tsx

PostToolUse · fragments hook · 47 ms

NotificationsForm.tsx:9FUI1004Bespoke <button> has a library equivalent. Swap to <Button> from @acme/ui.

NotificationsForm.tsx:10FUI2005Raw color #7c3aed on inline background. Use a token.

2 findings introduced · returned to the agent

The loop first. The gate second.Local while the agent writes. Required when the branch merges.

Keep your React library

Point it at the components you already ship. The manifest is yours to curate — no rewrite, no new library.

The loop runs in the editor

The agent reads your vocabulary before it writes and gets the repair the moment it drifts. Nothing leaves your machine.

The gate required to merge

Pin one contract id on the branch. The check passes, blocks or holds, and every verdict leaves a receipt.

Put it to work

Surfaces built for teams and their agents

From the session to the merge queue, the same manifest answers everywhere your interface code gets written.

fragments check --ci

The gate on every pull request

fragments/contract-compliance is the required check. One verdict per head against one FCID, with a receipt your reviewers can open.

fragments hook install

The loop in the editor

Claude Code, Cursor and Codex hooks read the card at session start, check each write, and refuse to stop while a finding is open.

fragments mcp --stdio

Local MCP search

search("three stats in a row") answers with the pattern and its exemplar from your own repository.

/evaluations/evr_…

Receipts

Every verdict persists as evr_… with the head, the FCID and the findings it introduced.

usefragments.com/errors

Versioned finding codes

Every finding carries an FUI code with a public explain page.

Works with the stackyou already run

See how it reads your repo
  • React
  • Next.js
  • Vite
  • TypeScript
  • Material UI
  • Radix
  • Chakra
  • Mantine
  • CSS
  • SCSS
  • CSS Modules
  • Tailwind
  • styled-components
  • Emotion
  • vanilla-extract
  • Storybook
  • GitHub Actions
  • Claude Code
  • Codex
  • Cursor
  • Copilot
  • MCP
Fragments UI · open source

A component library of our own

“The most explicitly AI-native design system we've seen … the most forward-thinking option available.”

Untitled UI, on AI-native design systems

Fragments UI is how teams adopt. Fragments Cloud is how teams enforce.

Browse componentsRead the piece
Cover of the Untitled UI piece: a tilted wall of library and tool logos — the Fragments star among GitHub, React, OpenAI, Tailwind and MUI.

Frequently asked questions

No. The manifest names your own Fragments and tokens — any React library. Fragments UI is an optional MIT starting point, not a prerequisite.

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