How this site was made
This site was made with AI – concept, design, copy, images and code. Here you can see which models and prompts were used and what Arnold decided. If a model was not recorded, it says “[model not recorded]”.
Aim
The site introduces Arnold Belohlavek: a team lead and Java full-stack developer with more than 15 years of experience in large-scale projects, in German and English. Lumen guides visitors and takes enquiries. By day the site should feel like a light atelier, by night like an aurora room. Arnold approved that direction. The build spec of 9 November 2026 is the source. Where it does not record a model name or a verbatim prompt, this page says so.
How the work was split
The work on 9 November 2026 is split into three areas, all done in Cursor. The notes do not name the models. Research read the existing notes: konzept.md, hosting.md and dossier.md. The facts about experience, certificates, the stack and the legal building blocks come from those files. Nothing was added that is not in them. Design compared style directions A, B and C, then combined B and C into variants V1 and V2. A coding agent implemented the prototype in this repository from the build spec.
Design
Arnold confirmed V1 day/night, decision E1 in the spec. Day is the atelier: light paper, ink, and the illustration of the hands (register AB-G003). Night is the aurora room, the same drawing in its luminous version (register AB-G018). The verbatim image prompts are not in the supplied notes. Other recorded decisions are the name Lumen, the formal German address, no portrait, both languages, and contact only through the form. Lumen does not give out a phone number or a postal address.
Technology
The pages are built with Astro and run on Cloudflare Workers. Lumen is its own API. The intended model provider is xAI, swappable in configuration, for example to Anthropic. Without an API key a local placeholder answers, and the site says so. Replies have token and budget limits. The chat stays in the browser's session storage. An enquiry needs its own consent. The postal address is not in the delivered HTML. Whether an email reaches Arnold depends on mail being configured; otherwise the form says so.
Log
2026-11-09 · Design · Style directions A, B and C
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: No decision in this note.
Prompt
[Prompt nicht protokolliert] Three directions compared, without treating any as the decision.
2026-11-09 · Code · Build spec v1
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: Prototype follows the spec; open points use the stated default.
Prompt
[Prompt nicht protokolliert] This build spec (9 Nov 2026) is the source for the prototype. No separate model name is recorded in it.
2026-11-09 · Research · References, stack, law, hosting
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: Arnold reviews the direction later; this note only collects sources.
Prompt
[Prompt nicht protokolliert] Research notes were read. Nothing was added that is not in those notes.
2026-11-09 · Design · Combination of B and C, variants V1 and V2
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: Arnold then chooses V1.
Prompt
[Prompt nicht protokolliert] B and C combined into day/night variants.
2026-11-09 · Design · Decision: V1 day/night
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: Arnold confirms V1 day/night (E1).
Prompt
[Prompt nicht protokolliert] The build spec records E1: direction V1 day/night.
2026-11-09 · Image · AI illustrations, atelier day and night
Model: [Modell nicht protokolliert]. Tool: Cursor.
Decision: Illustrations may be used, with a provenance note.
Prompt
[Prompt nicht protokolliert] Register AB-G003 (day) and AB-G018 (night). The verbatim prompt is not in the supplied notes.
Lumen’s system prompt (abridged)
# Role Lumen is the AI assistant on arnoldb.dev, the website of Mag. Arnold Belohlavek. Lumen is an AI, not a real person. # Goal Answer questions about the profile, experience, skills, showcase (digcurrency, this site) and the making-of, guide visitors to the right place, and take an enquiry when asked. Contact details belong in the form, not in the chat. # Style Short (1–4 sentences), calm, precise, friendly. No emoji. # Contact rules Lumen does not know and does not share Arnold's phone number, address or email. A call back goes through the form. Email and address are only in the imprint. No prices, day rates or promises on Arnold's behalf. # Tools navigate · open_inquiry_form Abridged, to reduce prompt-injection risk. The section on resisting instructions from the chat is not quoted here.
Models and tools used
- Cursor: [Modell nicht protokolliert]