The AS optimal spread formula gives absurd spreads at crypto scale.
Real market makers quote at the MARKET spread (best bid/ask) and use
AS to decide WHEN to quote based on inventory-adjusted fair value:
r = s - q * gamma * sigma^2 * tau
If r < best_bid (long-biased) → stop quoting bid
If r > best_ask (short-biased) → stop quoting ask
If circuit breaker active → pause both sides
Decoupled: spread is market-driven, inventory skew is AS-driven.