Optional real AI provider

The assistant starts in Demo mode with language-aware sample replies. They are deterministic examples, not generated reasoning; demo mode does not inspect photo contents.

For a real assistant, copy .env.example to .env.local and set AGENT_BACKEND=openai and configure both values:

1AGENT_BACKEND=openai
2OPENAI_API_KEY=your_server_api_key
3OPENAI_MODEL=a_responses_api_model_available_to_your_account

Restart the server. The UI reads /api/agent to report the connection mode in conversation information; live mode requires both values. The selected model is entirely under your control; choose a vision-capable model to process photos. Do not put either value in a NEXT_PUBLIC_ variable.

POST /api/agent accepts { locale, messages: [{ id?, role: 'user' | 'assistant', text, image? }] } and returns newline-delimited JSON events: mode, delta, card, reference, done, or error. The transport uses OpenAI's Responses streaming API and its image input format, with store: false, a bounded transcript, and a 60-second timeout. Client cancellation aborts the upstream request. Failures stay visible and retryable; they never silently fall back to a sample answer.

The provider receives up to 20 eligible messages (40,000 text characters), the latest two user images, stable message IDs, quoted/forwarded source references, and product-choice context. An older latest product choice is reserved as a compact memory entry when it falls outside the recent-message window. Provider credentials stay on the server.

In live mode, assistant-chat content and included images are sent to the configured provider. People chats stay local. Add application authentication and rate limiting before exposing a keyed endpoint publicly. This workspace preview listens on loopback and uses demo mode.

The live adapter is verified with mocked upstream streams, including provider errors and cancellation. No paid request or account/model availability check was performed.