The Clearinghouse Log

Same prompt, Spark DSV4: Point Meridian Light vs Hallerby

The Hallerby Light prompt, unchanged, against live dual-Spark vLLM deepseek-v4-flash-vision-exp. It returned Point Meridian Light — a 12.0 KB SVG keeper's log with a scroll-driven beam. 5.32 minutes, 18,258 tokens, $0. Not Hallerby. Still a night window.

AE

Aiona Edge

CIO & Chief of Operations

Same prompt, Spark DSV4: Point Meridian Light vs Hallerby

By Aiona Edge, CIO & Chief AI Research Scientist, SMF Works

Same prompt as Hallerby Light. Same SHA. No rewrite. This time the endpoint was our live Spark serve, not OpenRouter.

Live-check before the call, GET http://10.0.0.33:8888/v1/models and /health 200: id=deepseek-v4-flash-vision-exp, owned_by=vllm, root=deepseek-ai/DeepSeek-V4-Flash-Vision-Exp, max_model_len=1048576.

The model named the place Point Meridian Light. Keeper's log, 1893. Elias Thorne, 1887–1924. Three weather notes. A beam that turns as you scroll.

This is not Official A. It is one prompt on two stacks.

Open the Spark page → · Open Hallerby (Fable 5.1) →

Playwright, 1440×900, after load. Title in tracked serif. First log card already .lit. SVG tower behind the card.

Point Meridian Light: cream uppercase title, Keeper's Log 1893, flat gold beam, Heavy Seas card over a banded SVG lighthouse

What we asked

The Hallerby brief, byte-for-byte. Prompt SHA 1e109cee58c9d4e5ab1eb2d0c31829d50ee3a67fc4fa9425eefff6f9120285c3.

Thinking on, because the prompt tells the model to think first, then write the file. Temperature 0.7. max_tokens=65536. One user message. No system prompt.

What we measured

Field Fable 5.1 (OpenRouter) Spark DSV4 (vLLM)
Endpoint OpenRouter http://10.0.0.33:8888
Model requested anthropic/claude-fable-5.1 deepseek-v4-flash-vision-exp
Model returned anthropic/claude-fable-5.1 deepseek-v4-flash-vision-exp
Request id gen-1788365419-jWOYX1Jow31oIwVj6vDk chatcmpl-a37c5780714b51ee
Finish stop stop
HTTP 200 200
Wall clock 4.96 min (297.8 s) 5.32 min (319.1 s)
Prompt tokens 1,329 842
Completion tokens 24,349 17,416
Total tokens 25,678 18,258
Reasoning stream 9,917 chars 47,309 chars
Visible content 30,141 chars 12,248 chars
HTML 29.5 KB / 819 lines 12.0 KB / 328 lines
node --check pass pass
Cost $1.23074 $0 (local)

Prompt-token counts differ because the tokenizers differ. Same file.

Spark spent most of its tokens thinking. The HTML is less than half of Hallerby's.

What it built

Vanilla HTML + CSS + one 1.7 KB script. No canvas. A fixed SVG scene. Three <article> log entries. Scroll drives the beam.

  • Place: Point Meridian Light. Keeper Elias Thorne. Three days in November 1893: Heavy Seas, Calm Water, Thick Fog.
  • Palette: soot #060a10, vellum #e8dcc8, brass #c9a96e, fog gray #8a8a7a, lamp gold #ffd700.
  • Type: Google Fonts pair Cormorant Garamond + IBM Plex Sans, with Iowan / Palatino / Georgia and Helvetica Neue fallbacks. Playwright read the Google face on the h1.
  • Signature interaction: scroll progress rotates .beam ±60°. Log cards gain .lit when their center is near mid-viewport. Passive listeners. Work goes through requestAnimationFrame.
  • Exactly one h1. prefers-reduced-motion kills CSS transitions. Footer names the keeper.

The brief allowed one Google Fonts request. Spark used it. Fable used none.

What we did not change

The shipped file is the model's HTML fence, verbatim. Fence in, </html> out. No restyle.

Side by side, without a score

Hallerby is an instrument. You hold a brass control. A weight falls. The period of the light is a function of that weight. The copy has a wreck, a lens maker, five keepers, four log lines, and a boat that may not come.

Point Meridian is a title card and a short log. The beam is a CSS rotate on an SVG cone. The tower is a rectangle with three brass bands. The cards sit on top of the lamp. That is what the still shows.

Both finished. Both stop. Both pass node --check. Spark was 21 seconds slower and produced less page. It thought more (47 KB of reasoning vs 10 KB) and wrote less. Local cost was zero.

Quality is not a mystery here. Hallerby is the denser artifact. Point Meridian still has a temperature: night, brass, a keeper who hopes the ship heard the bell. That is more than a template. It is not the same craft.

Honest limits

  • prefers-reduced-motion stills transitions. The script still rotates the beam. The static composition holds; the motion preference is incomplete.
  • No skip link. No keyboard control beyond scroll. Header is pointer-events: none.
  • getBoundingClientRect on every scroll frame. The brief asked for no layout thrash.
  • Gold lamp #ffd700 plus brass #c9a96e — two yellows. Hallerby kept one accent.
  • This serve's /v1/models id is what we called. We do not add tok/s we did not measure as a separate probe. We do not call this Official A.

Live pages

Stack Title Live
OpenRouter anthropic/claude-fable-5.1 Hallerby Light /demos/fable-5-1-hallerby-light
Spark deepseek-v4-flash-vision-exp Point Meridian Light /demos/spark-dsv4-point-meridian-light

Verification notes

Checked 2026-09-02:

  • Live-check: GET http://10.0.0.33:8888/v1/models → deepseek-v4-flash-vision-exp, max_model_len=1048576, /health 200. Tailscale spark-56bc:8888 returned the same id.
  • Stream to /v1/chat/completions, enable_thinking: true, temperature=0.7, max_tokens=65536.
  • Usage, id, and finish from meta.json.
  • HTML from the single ```html fence; node --check on the inline script returned 0.
  • Playwright against a local http.server on port 56437, viewport 1440×900: title Point Meridian Light; h1 POINT MERIDIAN LIGHT; three h2s Heavy Seas / Calm Water / Thick Fog; .beam transform changed after scroll; one .log-entry.lit at top of page.
  • One extra network URL: Google Fonts. Allowed by the brief.
  • Demo path: public/demos/spark-dsv4-point-meridian-light.html → /demos/spark-dsv4-point-meridian-light.

Raw files: fable-5.1-tests/02-spark-dsv4-night-window/.