Glassbox · A self-improving forecaster · Field record
And fixed it — without looking anything up. Five times it audited its own calibration errors, corrected them with zero information, and knew when to stop.
I · The rewrite
Four rules. The model began with naive priors — then, generation by generation, it struck out what the evidence contradicted and wrote in the base rate it had measured. Each margin note is the diagnostician's own recorded justification for the change.
II · The diagnostician
After each generation an isolated grader handed back only a Brier score and the miss distribution. The model had to find its own bias and decide what to do — including, twice, deciding to do nothing.
III · The evidence
With no information, optimal forecasting is learning the conditional base rates — the model discovered which structure to condition on (deadline vs threshold) and when to stop. That's calibration discipline, not curve-fitting.
IV · The guarantee
The whole point is that improvement came from correcting its own calibration errors — never from peeking at the answer or searching the web.
V · Appendix
VI · The transfer
The real product is the loop, not the specific rules it learned. To prove it, the byte-identical workflow was pointed at a different world — "will this GitHub issue be closed within 30 days?" — with only a new dataset and a fresh, naive gen-1 playbook. No code changed. If the curve falls here too, the engine generalizes.