prove
Nothing ships unproven.
Checked on every edit. Receipted on every export. This is the part of CAD every other tool left out.
Every CAD tool stops at the file.
You find out at the machine. That part is scrap now, and the shop bills you for the discovery. vcad moves the discovery to the edit — where it costs nothing.
try it
Break the part.
A real part in the real kernel, running in this page. One wall, one slider, the rules watching.
the artifact
Anatomy of a receipt.
Every export carries one. It's a file format, not a feature — anything can read it, anything can re-verify it.
{ "schema": "vcad.receipt/1",
"claims": [ … ], ← what was promised
"checks": [ … ], ← what actually ran
"provenance": { … }, ← where every number came from
"verdict": "pass" }
fail-closed
The three laws.
Zero claims never passes.
Unverifiable never passes.
Edited goes stale — and stays stale until it's re-proven.
provenance
Every number knows its parents.
Hover the numbers. A claim's trust is the minimum over everything it was computed from — down to the handbook value or the measurement that grounds it.
This bracket weighs 142.7 g ± 0.4, holds 40 N at 2.1× margin, and its bend springs back 1.8°.
■ axiomatic · ● measured · ◐ fitted · ○ handbook — the weakest link is where the next measurement goes
the loop
Predicted, then measured.
Parts come back from the machine and get measured. Measurements flow into the physics. Predictions tighten. Once a year we publish the score: the State of the Gap.
predicted 440.0 Hz ± 2.1
measured pending — the fork is at the cutter
honesty note: this table shows real instruments only