A2UI Atomic Catalog — Developer Portal

Developer & Agent Documentation

Everything here is free, unauthenticated, and machine-readable — this developer portal is a human index into the same documents an agent reads.

1. Connect the MCP server

The primary integration surface. No API key, no signup.

POST https://a2uicatalog.ai/mcp
Content-Type: application/json

{"jsonrpc": "2.0", "id": 1, "method": "tools/list"}

GET the same URL with Accept: application/json for a live server descriptor — every tool, transport, and the current rate limits, generated from the running server so it cannot go stale:

curl -H "Accept: application/json" https://a2uicatalog.ai/mcp

2. Or use the REST surfaces directly

GET /spec.json	Full atom vocabulary — 573 atoms, every field contract
GET /catalogue/index.json	Compact catalog selection menu
GET /catalogue/atoms-json-schema.json	Strict per-atom JSON Schema for constrained decoding
POST /api/compose	Natural language → atom blocks

3. Reference & Developer Resources

• OpenAPI Spec (OpenAPI 3.1) — every endpoint, request/response schemas, examples
• API Docs — REST endpoints, error models, and rate limits
• API Reference & Docs — complete endpoint and parameter directory
• SDKs & Client Libraries — npm CLI/MCP package, Python A2A tools, and SDK generators
• Auth Docs — authentication overview, rate limits, and enterprise OAuth
• Webhooks Docs — SSE streaming, event delivery, and chat integrations
• API Versioning Policy — X-API-Version headers, deprecation timelines, and compatibility
• Pricing & Limits — free tier allowances and self-hosting runbooks
• agents.md — agent-facing guide, served as text/markdown
• llms.txt — short overview + entry points
• Auth & rate limits — the real per-tool numbers
• Authentication guide — why you probably need no credential, and the optional OAuth path if your platform requires one
• SDK Documentation — guide to client libraries and packages
• Versioning & deprecation policy — what changes without notice, and the CI gate that fails a deploy if a response shape changes undeclared
• MCP discovery manifest

4. Own your renderer

The shared demo renderer is rate limited by design. Deploy your own Apps Script renderer in four commands — no cost beyond a Google account — and every subsequent call targets it instead:

git clone https://github.com/a2uicatalog/a2ui
cd a2ui/apps-script-surface/gas-wired-renderer
clasp login && clasp create --type webapp && clasp push && clasp deploy

5. Auth

None required for normal use. See auth & rate limits for the optional OAuth/Basic-Auth paths used by platforms that require attributed access (e.g. Gemini Enterprise's BYO-MCP model).

Source

MIT licensed. Full source, issues and pull requests: github.com/a2uicatalog/a2ui.