# zxn.uk Chat

> Website live chat with an AI assistant, native iOS and Android inbox apps, and an agent surface (REST, webhooks, MCP, A2A).

## Machine interfaces
- REST API (OpenAPI 3.1): https://chat.zxn.uk/openapi.json  (human docs: https://chat.zxn.uk/docs)
- MCP server (Streamable HTTP): https://chat.zxn.uk/mcp  with header "Authorization: Bearer zxc_live_..." (API key from the app: Settings, Developers)
- A2A agent per site: https://chat.zxn.uk/a2a/{site_public_key}  (agent card: https://chat.zxn.uk/a2a/{site_public_key}/.well-known/agent-card.json), JSON-RPC methods message/send, message/stream, tasks/get, tasks/cancel
- Webhooks: Standard Webhooks signatures (webhook-id, webhook-timestamp, webhook-signature); events conversation.created, conversation.assigned, conversation.closed, message.created

## Auth
- Agents and integrations: "Authorization: Bearer zxc_live_..." (scoped: conversations:read, conversations:write, sites:read, sites:write, knowledge:write). Keys are workspace-bound.
- Visitors (widget API, /v1/widget): anonymous, X-Visitor-Token header issued by POST /v1/widget/session.

## Conventions
- JSON, snake_case, ISO-8601 UTC timestamps. Errors: {"error":{"code","message","fields?"}}. Pagination: ?limit&cursor -> {items,next_cursor}.
- Message creation is idempotent on client_id. Realtime: WebSocket /v1/workspaces/{ws}/socket?token=...&since=seq, or poll /v1/workspaces/{ws}/events?since=seq.

## Install the widget
<script src="https://chat.zxn.uk/w.js" data-site="site_pk_..." async></script>