A LONG-SHORT, SINGLE-INSTRUMENT crypto-native reversal strategy on ETHUSD.HYPERLIQUID perpetual futures using 1-HOUR bars CONFIRMED BY OPEN-INTEREST change (hl OI series). It is deliberately NOT a pure-OHLCV strategy: the entire signal hinges on the relationship between price direction and OI direction, which OHLCV-only strategies (the repeatedly-failed HL breakout / squeeze / opening-range siblings) cannot see. It fills the two loudest portfolio gaps at once — HYPERLIQUID venue (5.9% vs >=20% target) and long_short direction (14.5% vs the 85.5% long-only over-concentration) — while avoiding every documented failure family (no options/Deribit harness, no cross-sectional funding carry with decayed dispersion, no OHLCV breakout, no Bollinger fade, and distinct from the just-created liquidation-cascade fade). The mechanism trades the four canonical price/OI states but only ACTS on the two EXHAUSTION states where OI is CONTRACTING: a strong rally on FALLING OI is short-covering with no fresh long conviction (the up-move is hollow -> fade SHORT), and a sharp sell-off on FALLING OI is forced long-liquidation / capitulation (sellers exhausting -> fade LONG). When OI is RISING with the move (new money entering in the trade direction) we stand aside — that is a healthy trend we must not fade. Deliberately low-parameter (~4 core knobs: oi_window, price_move_thr, oi_drop_thr, plus one exit geometry) given the recurring overfitting failures, and the exit geometry is explicitly NON-inverted (take-profit target >= stop distance) to avoid the small-win/large-loss payoff trap that sank the COIN-M Bollinger strategy. RISK PROFILE: base risk 1.5% of equity per trade; volatility-based stop placed beyond the swing extreme of the exhaustion move (where the reversal thesis is invalidated); take-profit set at >= 1.0x the stop distance so avg_win is not structurally smaller than avg_loss; position size scales with divergence strength (larger price move + larger OI contraction => up to 3% risk, marginal divergence => 1%); max single-position exposure 20% of equity; hard time-stop of 36 hours (if the reversion has not begun the divergence was noise, exit flat); leverage 1.0.