Motor-timing gate solved with superhuman release precision or impossible claimed hold time
bh.arena_timing_superhuman · convicts
What it catches
Kitsune arena MOTOR-TIMING-PRECISION gate (arena/timing.go) — an original motor-precision tell, not a wild-captcha clone. The client holds+releases N targets, each for a shown duration within a tolerance. TWO SERVER-OBSERVED prongs make it forgery-closed: (1) PRECISION — the std of the release errors (hold - target) across targets. A human has an irreducible biomechanical jitter floor (tens of ms); a bot reporting the target-EXACT duration OR a flat CONSTANT offset both collapse the error std to ~0. A std below timingPrecisionFloorMs (25ms, well under any human) is superhuman motor precision. (2) IMPOSSIBILITY — the sum of the claimed holds vs the SERVER-OBSERVED solve age (issue->verify). A human performs the holds sequentially, so the elapsed always covers them; a bot that fakes human-like jitter but submits instantly claims more total hold time than the window could contain. Either prong -> anomaly:timing_superhuman; the detector relay (/arena/timing/verify) joins it to ks_sid so a PASS is CONVICTED on coherence. This CLOSES the forgery: you cannot fake precision (prong 1) AND cannot fake jitter without spending the real elapsed time (prong 2) — the only silent path is genuine human jitter + real time = a human. HUMAN-TIME + HUMAN-JITTER bound, HARDWARE-INDEPENDENT. FP-SAFE BY CONSTRUCTION: the std floor sits under human motor jitter and the elapsed always covers real holds -> precision 1.0 is load-bearing. GROUNDED LIVE 2026-07-09 THREE WAYS: a target-exact bot (std 0.0) convicts on precision; a fake-jitter-but-instant bot (std 61.9, sumHold 5557 >> instant age) convicts on impossibility; a human with the SAME 61.9 jitter who actually waits 4609ms is silent. Convicting (w0.85). See docs/research-radar.md (novel-arena-gates loop).
Signals it reads
behavioral.arena_timing_superhuman
How it fires
present
Bypassed by 10
Frontier evaders that reach the detector uncaught (scored only suspicious, defeating every convicting tell) — this check is not one that stops them. The red-team frontier this detection still has to convict.