a2uicatalog

# A2UI Atomic Catalog **Real rendered UI in the conversation — charts, gauges, dashboards, study apps — without the model writing a single line of HTML.** The agent names a component from a fixed vocabulary of 474 typed atoms. A renderer that already knows that component draws it. So a hallucinated atom is a *parse error*, not a broken screen — the failure surfaces before anything reaches the user. No signup, no API key, no configuration. Add the URL and start. ``` https://a2uicatalog.ai/mcp ``` ## Try it > Using the A2UI catalog, render a stat_card with value "1,234", label "Daily users", delta "+12%". > Build me a full-screen revision app for the French Brevet — subject tabs for Maths, > Français and Histoire-Géo, with flashcards and a timed drill in each. > Show a live ATC radar for Toulouse with simulated traffic and the real LFBO weather. The second one is a single tool call: `emit_runbook_surface` stamps your content through a pre-authored composition, so the agent supplies content and makes zero layout decisions. The third pulls live METAR through a declared data proxy. ## One payload, many surfaces Every atom declares where it works, where it degrades, and where it genuinely cannot go — and those declarations are **enforced**, not documentation: | | | |---|---| | `works_on` | renders fully | | `degraded_on` | renders with something lost — an animation frozen, an ordered list instead of a stepper | | `incompatible_on` | cannot do what it is designed to do there, and says so instead of pretending | A `quiz_set` you cannot answer is not a degraded quiz, it is not a quiz. The catalogue refuses rather than shipping something that looks right and isn't. Surfaces: **web · MCP Apps · Google Apps Script · Google Meet · Google Chat · PDF · email** ## Interactive UI, not screenshots Implements **MCP Apps (SEP-1865)** — `ui://` resources over the standard `ui/*` JSON-RPC bridge. Verified rendering full-screen in **both Claude and ChatGPT** from an identical payload, which is the point: the vocabulary is the product, the host is a detail. ## 15 tools **Compose** — `list_catalogs`, `get_catalog`, `required_catalogs`, `distill_document` **Render** — `render_surface`, `render_ping`, `preview_url`, `make_surface_url`, `build_multi_page_surface` **Runbooks** — `emit_runbook_surface`, `emit_training_runbook` (pre-authored compositions; you supply content only) **Ship** — `emit_deployment`, `publish_url`, `unpublish_url` **Setup** — `identify_model` (capability-matched guidance; optional, never a precondition) ## Without MCP at all The vocabulary stands alone. No client, no connector, no account: ```bash curl -X POST https://a2uicatalog.ai/api/render \ -H 'Content-Type: application/json' \ -d '{"blocks":[{"type":"stat_card","value":"1,234","label":"Daily users"}]}' npx -p @a2uicatalog/mcp a2ui render page.json --surface email ``` `OpenAPI` · `spec.json` · `llms.txt` · ARD catalog — all public, all unauthenticated. ## Free No paid tier, because there is nothing to upgrade to. MIT licensed, renderers in the public repo — anything you hit a limit on here, you can run yourself. Full limits: https://a2uicatalog.ai/pricing.md --- [Docs](https://a2uicatalog.ai/llms.txt) · [OpenAPI](https://a2uicatalog.ai/openapi.json) · [Source](https://github.com/a2uicatalog/a2ui) · MIT

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here B, 77.6/100), which weighs availability, conformance, p95 speed and descriptor. How the two differ

Compared with peers

Against 53,039 reachable MCP servers in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.

Readiness

Higher than 52% of peers

This listing 81 · peer median 81

Latency

Faster than 27% of peers

This listing 538 ms · peer median 326 ms

How many agent tools actually work · All statistics

Listed in

Directories this entry was found in.

How to connect

https://server.smithery.ai/a2uicatalog/a2uicatalog/mcp

curl -X POST https://server.smithery.ai/a2uicatalog/a2uicatalog/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'