Pixel Path

Builds a folder you can open or host: index.html with road.js and layout.js (the fly-through), data/ (the baked route) and art/ (the pictures). Plain Node 18+, no npm installs (the self-check uses Playwright if present). Scripts are in ${CLAUDE_SKILL_DIR}/scripts/; run them as node ${CLAUDE_SKILL_DIR}/scripts/<name>.mjs .... Call the trip folder TRIP (e.g. trips/bath-bristol). Every step can be rerun and resumes where it stopped.

The result is a first-person camera moving along the real road: the real buildings on their footprints, the real landmarks at their places, real land cover, hills and horizon. No interface beyond a small credits line. Scroll (or drag on a touch screen) to speed up, slow down or reverse.

Before you start, tell the user

• Only the art costs money, paid to RetroDiffusion from the user's own account. Routing, map data and the viewer are free. Step 1 prints an estimate for their route at each level: show it to them and let them pick a level (or free placeholders) before you bake or generate anything.
• No account? Send them to https://www.retrodiffusion.ai?ref=YBQJM823 and say that it is an affiliate link (the author of this skill gets a referral). They create an API key and set it in their own terminal: export RETRODIFFUSION_API_KEY=... (on a Mac they can store it in the Keychain instead: security add-generic-password -s pixel-path -a retrodiffusion -w). Never ask for the key in the chat, never print it, echo it or write it to a file.
• Attribution is required. The credits line (OpenStreetMap, OSRM, Terrain Tiles, Wikidata, RetroDiffusion) must stay visible wherever the fly-through is shown.
• Time. Baking takes about 20 to 60 seconds per 10 km. Run long bakes in the background.

The levels

Per region (a region is one look, e.g. "Georgian Bath"); $0.18 a picture at RetroDiffusion rd_pro__default (October 2026). The levels are nested: moving up a level only pays for the new pictures.

level	per region	1 region / 2 regions	what you get
placeholders	0	$0 / $0	code-drawn stand-ins for every picture
sparse	4	4 / 8 pictures, $0.72 / $1.44	3 kinds of building and a tree; every lot still filled, mirrored and tinted copies stretch the few pictures
moderate	about 14 + 4 landmarks	18 / 32 pictures, $3.24 / $5.76	about 10 buildings over the main kinds, 2 trees, a shrub, a street prop, the 4 best-known landmarks
detailed	about 26 + 10 landmarks	36 / 62 pictures, $6.48 / $11.16	up to 6 variants of each kind of building (up to 9 kinds), 3 trees, 2 shrubs, 3 street props, 10 landmarks

Steps

1. Route and estimate (free, seconds)

node ${CLAUDE_SKILL_DIR}/scripts/route.mjs --out TRIP --from "Bath, England" --to "Bristol, England" [--via "Keynsham"]

Places can be names or "lat,lon"; add the region or country if a name is ambiguous. The start's country sets which side you drive on, miles or km on signs, and a yellow centre line in North America. It prints the distance and the estimate table (pictures and dollars for each level): show it and ask which level. NoRoute means no road connects them: add a --via on the road network. Set PIXEL_PATH_USER_AGENT="name/1.0 (email)" so the services know who asks.

2. Bake (free, slow)

node ${CLAUDE_SKILL_DIR}/scripts/bake.mjs --trip TRIP [--default-land desert]

--default-land desert for arid routes. It prints, per 10 km, the buildings, land mix and place names, and at the end the best-known landmarks near the road: use them to choose regions and subjects. On Overpass errors it waits and retries across mirrors; if it still fails, rerun later (finished chunks are kept).

3. Plan the art (free)

One region (theme) per distinct look: usually 1 for a short or uniform route, 2 or 3 for city, countryside, another city. A region is id|starts at km|description. Write specific subjects: generic prompts give generic buildings, and the subject is what makes a place recognisable. Give up to 6 alternatives per role separated by | (each variant takes the next one). For landmarks, describe what the building looks like from the street (--subject "lm-<wikidata id>=..."): the model does not know the building by name.

node ${CLAUDE_SKILL_DIR}/scripts/plan-art.mjs --trip TRIP --detail moderate \
  --theme "bath|0|the Georgian city of Bath, England: honey-coloured Bath stone" \
  --theme "bristol|11|Bristol, England: red brick and pastel-painted Victorian terraces" \
  --subject "bath:terrace=a three-storey Georgian townhouse of Bath stone in a terrace, sash windows, a black door|..." \
  --subject "bath:shop=a Georgian Bath stone building with a painted wooden shopfront, invented name|..." \
  --subject "lm-Q2540426=the Roman Baths: a Bath stone colonnade and the Pump Room front with tall columns"
node ${CLAUDE_SKILL_DIR}/scripts/placeholder-art.mjs --trip TRIP

Kinds of building (house, terrace, shop, apartment, tower, civic, church, industrial, farm) get pictures in proportion to how much of the frontage they cover; other roles are tree, bush, street and the landmarks. Read the printed list and fix subjects that don't fit. The prompts already spell out the view and the isolation. Never ask for real brand logos, real business names or recognisable people.

4. Quote, confirm, generate

node ${CLAUDE_SKILL_DIR}/scripts/rd.mjs quote --trip TRIP                 # free: the exact total and the account balance
node ${CLAUDE_SKILL_DIR}/scripts/rd.mjs run --trip TRIP --budget 6.50     # only after the user confirms the budget

--budget is the trip's total including what it already spent; suggest about 25% over the quote for re-rolls (in tests, 10 to 35% of pictures came back unusable and were re-rolled). Every job is quoted and reserved in art/ledger.json before it is paid for; the run stops rather than go over the budget or the balance, and reruns never pay twice. Exit 3 means no key.

5. Clean (free), then look at the contact sheet

node ${CLAUDE_SKILL_DIR}/scripts/clean.mjs --trip TRIP

Floods away white backdrops, fills see-through holes in facades, hardens edges, crops, and drops pictures that still carry a background (over 55% of the outline opaque), painted sky, cut-off subjects or slivers. Open TRIP/art/contact.png with the Read tool and look at every picture. Add any that look wrong (a building at an angle, two buildings in one picture, a sign with a real brand, anything that would not stand on its own in a street) to TRIP/art/drop.txt, one name per line, and re-clean.

6. Self-check (do not skip it, do not stop while it reports problems)

node ${CLAUDE_SKILL_DIR}/scripts/check.mjs --trip TRIP [--fix --budget 6.50]

It installs the page, lays out the whole route exactly as the page will, and then, in headless Chromium:

• sweeps the whole route: every 75 m of built-up road, with the camera moving, looking straight ahead and 30 degrees to each side, the sky painted magenta and every building drawn into a mask. It counts sky seen through a building and slits of sky between two parts of the same street wall reaching down to the ground, and writes the 20 worst frames to TRIP/check/worst-frames.png (each frame as it looks, beside the same frame with the problem marked);
• renders sample frames (TRIP/check/montage.png, shot-*.png) and checks they are readable and named;
• reports gaps in built-up street walls, a building with the same picture as its neighbour, and dropped art. --fix re-rolls dropped pictures within the budget and checks again. The frame checks need Node 20+ and Playwright (npm i -D playwright && npx playwright install chromium); without them, say plainly that the trip was not swept.

7. Look, then fix, until it is clean

Read TRIP/check/worst-frames.png, TRIP/check/montage.png and the shot-*.png frames. The trip is done only when the sweep reports no frames with sky through or between buildings and every frame you look at passes these questions: can you tell where you are (buildings, signs, landmarks)? Is there a gap in a street, sky through or behind a building, a building that looks like a flat card, a floating fragment, the same building twice side by side? Is anything broken, on a background, cut off, enormous or tiny? Fix what you find: a bad picture goes in drop.txt and rd.mjs run --regen NAME (it costs a picture: say so first); generic pictures need better subjects and --regen; a region that looks wrong needs another region. Run the check again after every fix. Tell the user honestly what is still imperfect.

8. View and hand over

node ${CLAUDE_SKILL_DIR}/scripts/viewer.mjs --trip TRIP --serve 8080     # then open http://127.0.0.1:8080/

Any static server works (file:// does not). To host, upload index.html, road.js, layout.js, data/ and art/ (not .cache/, art/raw/, art/ledger.json). Controls: scroll or drag to go faster or slower (keep going to reverse), arrow keys the same, Space pauses, I shows where you are, M a small map. URL options: ?km=3.2&speed=60&info=1&map=1.

Being polite to the services

One script at a time per service, with the built-in pauses. Everything is cached in TRIP/.cache, so reruns cost the services nothing. Never run several bakes in parallel; for many or very long routes, self-host OSRM and Overpass.

Credits and licences (attribution required)

• Map data © OpenStreetMap contributors, Open Database Licence (ODbL): https://www.openstreetmap.org/copyright. The baked data/ is a derived database: if you share it publicly it stays under the ODbL, with attribution.
• Routing: OSRM, from OpenStreetMap data. Geocoding: Nominatim (OpenStreetMap Foundation), under its usage policy.
• Elevation: Terrain Tiles (Mapzen/Tilezen on AWS Open Data): https://github.com/tilezen/joerd/blob/master/docs/attribution.md
• Landmarks: Wikidata (CC0).
• Art: generated with RetroDiffusion (https://www.retrodiffusion.ai?ref=YBQJM823, affiliate link) on the user's own account, under RetroDiffusion's terms.

RetroDiffusion API assumptions (checked October 2026)

POST https://api.retrodiffusion.ai/v2/inferences with header X-RD-Token; body prompt, prompt_style, width, height, num_images, seed, remove_bg, input_palette; check_cost: true returns balance_cost and remaining_balance for free; results in base64_images, or a task_id polled at GET /v2/inferences/tasks/<id>. Trust rd.mjs quote over the prices above. If the API changes, adjust bodyOf() and api() in rd.mjs.

Files

• scripts/route.mjs (with the estimate), bake.mjs; kit.mjs (roles, prompt recipes, levels); plan-art.mjs, rd.mjs, clean.mjs, placeholder-art.mjs; viewer.mjs, check.mjs; lib.mjs.
• templates/viewer.html, road.js, layout.js: the fly-through (commented, to be read). templates/palette.png: the shared palette that keeps a kit coherent.