What this lens asks: how volatile is the tape right now, and how does that change which strategies work and how big I can size? Volatility is the cross-cutting filter that governs both strategy fit and position size. In low-volatility grinds, trends are smooth and stops can be tight, but breakouts often fail to follow through. In high-volatility whipsaw, stops get hit on noise, gaps jump entries, and position size must shrink because ATR-based risk per share balloons. Volatility also clusters and mean-reverts — quiet begets quiet until it doesn't — so the expansion/contraction cycle itself signals what to expect next.

This is a lens (synthesis) node, not the volatility-mechanics catalog. The object-level building blocks — implied vs realized volatility, the VIX complex, skew, and term structure — live in Derivatives & Options → Volatility Trading (domain #917) and are not duplicated here. What this branch adds is the application:

• How Strategies Degrade by Vol Regime (the synthesis doc in this section) — how each volatility phase favors or punishes different strategies, and the practical levers: volatility-scaled position sizing (constant dollar-risk via ATR), wider stops in high vol, and avoiding fixed share-count sizing.

Honest caveat: volatility regime is itself only known with a lag, and naive vol-targeting can whipsaw; whether timing volatility adds alpha (beyond using it to scale risk) is genuinely contested in the literature.

For the Augustus swing agent: vol regime should modulate both the go/no-go decision and the stop/size of any proposed swing — a strong-looking setup in a high-vol whipsaw warrants smaller size and wider invalidation, or no trade at all.

Related: [[how-strategies-degrade-by-vol-regime]] · Derivatives & Options / Volatility Trading (#917) · the companion lenses [[timeframe-and-holding-period]] and [[market-regime]].