UCP Score for 4window.cz

{
  "keys": [
    {
      "kty": "EC",
      "crv": "P-256",
      "x": "<base64url x>",
      "y": "<base64url y>",
      "kid": "store-2026-10",
      "use": "sig",
      "alg": "ES256"
    }
  ],
  "ucp": { ... }
}

Create a P-256 (ES256) key pair: ES256 is the one algorithm every UCP agent must be able to check. Add the public key to a "keys" list at the top level of your UCP profile, as in the example, with its own "kid", and keep the private key on your server. The spec recommends a new key every 90 days: publish the new one next to the old, sign with it, and remove the old key a week later.

# llms.txt
# Public brief for AI agents about Yourstore

# About
One or two sentences on what you sell, who you sell to, and any defining context (founded, mission, sustainability stance, etc.).

# Product Categories
- Category one
- Category two
- Category three

# Policies
- Returns: e.g. 30 days, full refund
- Shipping: e.g. Free over $30, 3-5 business days
- Any other policy worth surfacing (cruelty-free, vegan, made-to-order, etc.)

# Agent Capabilities
- UCP profile: /.well-known/ucp
- Supported flows: cart, checkout, tokenized payment, etc.
- Anything explicitly NOT supported (e.g. "no subscription products via agent")

# Contact
[email protected]

Save as /llms.txt at your site root. Plain text, written for an LLM audience. The format is informal: these section headings are a working convention, not a spec. Replace the placeholders with your own brand details and update when policies or product lines change.