THE HOME GROUND · THE MARKET ROW · Nº 1222 · EDITION 1 · LAUNCHING SOON
LUND CARDS · THE HOME GROUNDNº 1222
THE CARD AS TEXT · FOR EYES AND FOR MACHINES
THE FOOT FIT · Feet measured right and both sides checked, sealed into a fit record. The fit math stays on the service.
WAKES WHEN Someone measures their feet for a shoe fit. · Left and right measurements disagree. · A fit record needs sealing to send to a fit service.
THE LOOP
Take both feet, standing
Check ranges and left-right agreement
Seal the fit record with its hash
Prepare the request; read the maker's chart
NEVER
Never shapes a last or prescribes a shoe
Never seals a record that failed its check
Never gives medical advice
IT MAKES check — every value present and plausible, left/right agree, measured standing, measured_on not after --today; record — only if check passes, writes FIT-RECORD.json with a sha256 of the measurements into the folder you run it from; --out names another folder (file FIT-RECORD.json inside it) or a full file path; request — only if check passes, writes FIT-REQUEST.json, the request a fit service would receive, into the folder you run it from (--out as for record); the studio's fit service is planned and not yet open; nothing is sent; brand-size — the size your chart gives for the longer foot, or OFF CHART.
THE LAW The card measures and checks; the fit is made elsewhere. Nothing in this box holds a fitting method, and the card says so. It prepares a clean, sealed record and stops.
PROOF SELFTEST 19/19 · witnessed in Claude 2026-10-13 on fictional fixtures · the test prompts in fresh chats owed · Edition 1.
THE SEAL 96 of 100 · LEGENDARY · WITNESSED · Trigger 5 · Machinery 5 · Law 5 · Portability 5 · Proof 4
IT CAN BE WRONG an AI reading a text file: it can be wrong and can invent a number, a rule, a name or a date; check what matters against your own records and the source; the risk is yours. LICENSE-NOTE.md rides in the packet and is the licence.
THE PUNCH · SHA-256 OF SKILL.MD · 09349399CD8897728D830877
CITE THIS CARDTHE FOOT FIT, Edition 1. Lund Studio LLC, Westminster, Colorado. https://lundr.tech/?view=foot-fit-card. Punch 09349399CD8897728D830877. Retrieved 2026-10-13.
What it is.
Use when taking foot measurements for a fit: checking both feet, re-measuring outliers, sealing a fit record and reading a maker's size chart. Not medical or podiatry advice.
It carries a machine that shows its working: check — every value present and plausible, left/right agree, measured standing, measured_on not after --today; record — only if check passes, writes FIT-RECORD.json with a sha256 of the measurements into the folder you run it from; --out names another folder (file FIT-RECORD.json inside it) or a full file path; request — only if check passes, writes FIT-REQUEST.json, the request a fit service would receive, into the folder you run it from (--out as for record); the studio's fit service is planned and not yet open; nothing is sent; brand-size — the size your chart gives for the longer foot, or OFF CHART — 19 checks in its selftest. It never shapes a last or prescribes a shoe; never seals a record that failed its check; never gives medical advice.
The law, written into the card.
It is in the card itself, so the AI follows it.
THE LAWThe card measures and checks; the fit is made elsewhere. Nothing in this box holds a fitting method, and the card says so. It prepares a clean, sealed record and stops.
The method.
Measure both feet standing: length, width, arch height and instep girth, with the method written down.
Check each value against plausible human ranges and check left against right. Too far apart prints RE-MEASURE; not standing prints RE-MEASURE STANDING.
Seal the record with a hash of the measurements, only after the check passes.
Write the request a fit service would receive. The card does not send it.
If the buyer brings a maker's size chart, read the size for the longer foot from it, or print OFF CHART.
What you bring.
Your measurements, both feet, standing.
A maker's size chart, if you want a chart size.
Planned as a separate seat, not in this box and not yet on sale: a fit service that turns a sealed fit record into a fit.
What it does once your AI has it.
check Every value present and plausible, left/right agree, measured standing, measured_on not after --today
record Only if check passes, writes FIT-RECORD.json with a sha256 of the measurements into the folder you run it from; --out names another folder (file FIT-RECORD.json inside it) or a full file path
request Only if check passes, writes FIT-REQUEST.json, the request a fit service would receive, into the folder you run it from (--out as for record); the studio's fit service is planned and not yet open; nothing is sent
brand-size The size your chart gives for the longer foot, or OFF CHART
What it will never do.
It never shapes a last or prescribes a shoe; never seals a record that failed its check; never gives medical advice.
Where it hands off: Foot pain or injury → a clinician; Shoe mileage → THE SHOE MILES; The fit itself → a fit service (the studio's is planned, not yet open).
It is not medical advice. It is an AI reading a text file: it can be wrong, so check what matters against your own records and the source. The holder brings their own AI; no endorsement by Anthropic or any other AI company is claimed.
What’s in the buy.
SKILL.md — the card your AI reads: when it wakes, the loop, the never-lines, the hand-offs.
CARD.md — the whole card in ten sections: face, law, method, machine, what you bring, never, tests, seal, term.
scripts/footfit.py — the machine, Python standard library only; `selftest` proves it on its own fixtures.
tests/EVALS.json and scripts/evals.py — 8 test prompts and the offline runner that scores your AI's answers.
references/ — the data schema and FICTIONAL demo files, invented to show the machine, not real.
MY-LEDGER.md — your own record of what you asked and what you decided.
START-HERE.md, system/short-prompt.md, system/rules.md — the doors, for any AI with or without skills.
card.svg, card.json, card.html, AUDIT.md, MANIFEST.md, WITNESS.md, SELFTEST.md — the faces and the proof.
NOT IN THE BOX — any studio edition (planned, not yet on sale: a fit service that turns a sealed fit record into a fit). Also not in the box: any data you must bring, and advice of any kind (not medical advice).
PROOF · SELFTEST 19/19 · WITNESSED IN CLAUDE 2026-10-13 ON FICTIONAL FIXTURES · THE TEST PROMPTS IN FRESH CHATS OWED · EDITION 1 · PUNCH 09349399CD8897728D830877
ON EVERY DOOR · A CARD FOR YOUR AI, A FILE FOR YOUR COMPUTER
In Claude: turn on code execution under Settings › Capabilities, then Customize › Skills › + › Create skill, and upload the zip as it is — START-HERE.md in the box walks you through it, and tells you how to keep the ledger. In ChatGPT, Gemini and the rest: a Project, a GPT or a Gem with the card’s files attached and the short door in the box pasted as its instructions. The words run anywhere an AI reads Markdown; the machines run wherever the host runs Python. Witnessed in Claude only. The host marks →
Take it.
Nº 1222 — LAUNCHING SOON
Sold as is under the term printed. A card instructs an AI you operate; results depend on your model, your files and your judgement. Not medical, legal, tax or financial advice, never the person’s boss, and not a licence to practise. The terms →
One payment. The file is yours to keep and keeps working at its edition; new editions issued in the year after you buy reach you by email as replacement files. Tax is added at checkout where it applies. Nothing auto-renews.
A TERM, NOT A SUBSCRIPTION: NOTHING RENEWS ITSELF AND NOBODY IS CHARGED AGAIN. WHEN A TERM ENDS THE FILES STAY ON YOUR COMPUTER AND STAY READABLE — FREEZE, NOT LOSS.
THE MACHINE · IN THE OPEN · FROM THE CARD’S OWN SELFTEST.MD
footfit.py, every command showing its working.
A small Python program, standard library only. Your AI runs it; you can too. The block below is pasted from the card’s own SELFTEST.md, as printed when it was run from inside the packet.
check
every value present and plausible, left/right agree, measured standing, measured_on not after --today
record
only if check passes, writes FIT-RECORD.json with a sha256 of the measurements into the folder you run it from; --out names another folder (file FIT-RECORD.json inside it) or a full file path
request
only if check passes, writes FIT-REQUEST.json, the request a fit service would receive, into the folder you run it from (--out as for record); the studio's fit service is planned and not yet open; nothing is sent
brand-size
the size your chart gives for the longer foot, or OFF CHART
selftest
19 checks that prove the machine; it must print selftest 19/19
THE SELFTEST, AS PRINTED
ok 1 good measurements PASS and the fit-math line is printed
ok 2 length 350 mm is OUT OF RANGE (exit 1)
ok 3 a missing value prints MISSING, nothing filled in
ok 4 left/right length differ by 8 mm (over 6) → RE-MEASURE
ok 5 left/right width differ by 6 mm (over 5) → RE-MEASURE
ok 6 not measured standing → RE-MEASURE STANDING
ok 7 record writes FIT-RECORD.json whose sha256 matches the measurements
ok 8 record is deterministic (same bytes twice)
ok 9 record refuses when check fails and writes nothing
ok 10 request writes the JSON (sent=false), says the fit service is planned and not yet open and nothing is sent, imports no network module
ok 11 no line claims a fit service exists (no seat-key or lives-on-the-service wording anywhere)
ok 12 request refuses an endpoint that is not http(s) (exit 2)
ok 13 brand-size uses the longer foot (right 265) and returns the chart's size 9 only
ok 14 brand-size in a gap between chart rows → OFF CHART, no size given (exit 1)
ok 15 --range overrides a default plausible range
ok 16 with no --out, record and request write FIT-RECORD.json / FIT-REQUEST.json in the folder run from, not beside measure.json
ok 17 --out naming a folder writes FIT-REQUEST.json inside it
ok 18 measured_on 2026-05-01 after --today 2026-04-02 → FUTURE DATE, does not pass (exit 1); on the day itself it passes
ok 19 record refuses a future-dated measurement and writes nothing
selftest 19/19
THE RUN IS PASTED FROM THE CARD’S OWN SELFTEST.MD AS PRINTED. ITS FIXTURES ARE FICTIONAL, INVENTED FOR THE TEST; NO PRIVATE PERSON IS NAMED.
QUESTIONS AT THE TABLE
Asked before the wire.
What does it need from me?
Your measurements, both feet, standing. A maker's size chart, if you want a chart size. If something it needs is missing, it says what is missing and stops there.
Does it send anything anywhere?
No. The machine is a standard-library Python program that runs on your own computer and sends nothing anywhere; the words run wherever an AI reads Markdown. No server, no account, no key.
What is on the record?
The machine's selftest (19/19), run from inside the packet in Claude on 2026-10-13 on fictional fixtures and pasted into SELFTEST.md as printed; the twelve-check audit (AUDIT.md). Owed, and said so in WITNESS.md: The 8 test prompts asked in fresh chats with the card installed. Until they are run and scored, the tests are owed. Any run on real data. Every demo file is fictional. The punch on the face is the SHA-256 of SKILL.md, so a downloaded copy can be checked against this room.
Can it be wrong?
Yes — it is an AI reading a text file: it can be wrong and can invent a number, a rule, a name or a date; check what matters against your own records and the source; the risk is yours. LICENSE-NOTE.md rides in the packet and is the licence. It is not medical advice.
What will it never do?
It never shapes a last or prescribes a shoe; never seals a record that failed its check; never gives medical advice.
