Arete Diamond — for AI agents

Certified loose diamonds (GIA/IGI/HRD) and made-to-order fine jewellery. Retail prices, VAT-aware, EU delivery from Prague, Czech Republic. Loose diamonds are procured per order (backorder with a stated delivery time); jewellery is made to order. Agents can search, configure and price everything below — payment is always completed by a human via a secure hand-off link.

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Discovery

llms.txt — Concise markdown index of this whole surface (llmstxt.org convention).
API catalog — RFC 9727 linkset — machine-readable table of contents.
OpenAPI spec — OpenAPI 3.1 description of the product feeds, MCP and ACP/commerce surfaces.
Agent authentication — How to get an ak_ API key or an OAuth token; an API key is currently required for MCP requests.

MCP — Model Context Protocol

One endpoint, 15 tools: diamond search and detail, jewellery browsing and configuration, retail pricing, an educational encyclopedia, shipping and exchange rates, and a checkout hand-off that always ends with a human.

MCP endpoint — Streamable HTTP, JSON-RPC. An ak_ API key is required (240 req/min).
Server card — Endpoint + capabilities descriptor.
A2A agent card — Agent2Agent card mapping the MCP tools to skills (legacy alias at /.well-known/agent.json).
Agent-skills index — Agent Skills discovery index with a digest-verified SKILL.md.

ACP / UCP — agentic commerce

Checkout sessions are live: agents can assemble a cart and receive a secure hand-off link; payment is always completed by a human.

ACP discovery — Agentic Commerce Protocol manifest — catalog search/lookup and the checkout endpoint.
UCP profile — Universal Commerce Protocol discovery profile over the same endpoints.
ACP diamond feed — Paginated loose-diamond discovery feed (search-only; deep-links to product pages).

Product feeds

ChatGPT product feed — OpenAI Commerce format. ?country=CZ|SK|DE|GB with matching ?locale=cs|sk|de|en; jewellery by default, loose diamonds via ?gem_type=…&page=0; ?format=json|ndjson.
Sitemap — Sitemap index — pages, jewellery, loose diamonds, all locales.

Policy. Content-Signal: search=yes, ai-train=no, ai-input=yes — you may access and ground answers on this content; do not use it for model training. Catalogue reads currently require an ak_ API key (240 req/min keyed). API keys & agent access: [email protected].