Your chess rating has a range.
You play, the number wobbles, and you can't tell whether you're improving or just moving. Arcifact measures the range behind your rating and tells you when a change is real. When the evidence can't support an answer, it says so, which is rarer than it should be.
88.2 million evaluated games across twelve months of the public Lichess record.
Every claim gated. Interval coverage and false-fire rates are measured and published before anything is said to anyone.
Failures published. Four popular improvement theories failed our negative controls. So did one of our own proposed upgrades. Both are in the public ledger.
Status
The instrument is calibrated and the receipts are already public. The site opens shortly; the founding rate is honoured from the first day. Until then, the ledger linked above is live and checkable.