Point-localization gate solved with a pixel-perfect centroid click or impossibly fast
bh.arena_localize_superhuman · convicts
What it catches
Kitsune arena POINT-LOCALIZATION gate (arena/locate.go) — the hCaptcha 'click the center of X' / AWS WAF family, reproduced as owned infra (no clone/asset). A canvas is rendered with distractor disks + one target-coloured disk; the client must click the CENTRE of the named target. The target centre is rendered into the PNG and kept SERVER-SIDE (not in the payload), so passing requires actually LOCATING the object (visual / CV) — free-canvas localization, not tile-select. TWO SERVER-OBSERVED prongs: (1) PIXEL-PERFECT — the click distance to the true centroid. A CV solver segments the target and clicks its computed centroid EXACTLY (distance ~ 0); a human aims by eye and lands tens of px off. A distance below localizePixelFloor (2.5px) is a computed click, not human aim — the distinctive localization tell. (2) SUPERHUMAN SPEED — the whole solve (SERVER-OBSERVED age, issue->verify) faster than localizeFloorMs (500ms), under a human's visual-locate + aim time. Either prong -> anomaly:localize_superhuman; the detector relay (/arena/locate/verify) joins it to ks_sid so a PASS is CONVICTED on coherence (the arena thesis: the solve-BEHAVIOUR discriminates, not the puzzle). FP-SAFE BY CONSTRUCTION: the acceptance radius (34px) admits ordinary human aim while the pixel floor (2.5px) sits far below human click variance on a ~20px target; the age floor bounds human visual-locate time (hardware-independent). EXPERIMENTAL (w0.85, calibration: widen localizePixelFloor if a careful human is seen clicking dead-centre on the easy level; the RED evader that jitters its centroid click by >2.5px evades prong 1 — which is the arena point, the gate raises the bar). Test both directions: a centroid-computing CV click (dist ~ 0) or an instant solve convicts; a human eyeballing the centre (dist 8-25px, > 500ms) is silent.
Signals it reads
behavioral.arena_localize_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.