> ## Documentation Index > Fetch the complete documentation index at: https://pegana.xyz/docs/llms.txt > Use this file to discover all available pages before exploring further. # Why hysteresis matters in peg detection > If a stable hovers around the drift threshold, a naive monitor will fire an alert every tick. Pegana's hysteretic FSM uses asymmetric enter/exit thresholds and dwell timers so a real transition emits one alert, not a hundred. Every peg-monitoring system eventually faces the same problem: a noisy signal that crosses a threshold a dozen times in a single minute. The first alert is useful. The next ninety-nine are spam — and the user mutes the channel within an hour. The fix is **hysteresis**. Hysteresis means a state machine remembers where it came from. Going up needs a higher threshold than coming back down. It's the same logic a household thermostat uses: heat turns on at 19°C, but won't turn off until the room reaches 21°C. Without that gap, the heater clicks on and off every few seconds. ## The state ladder, explicitly Pegana has five peg states for every monitored asset: * `PEGGED` — spread inside the calm band; no alert. * `DRIFT` — spread crossed the per-asset drift threshold; subscribers are notified. * `DEPEG` — spread crossed depeg; more urgent alert framing. * `CRITICAL` — spread crossed critical; the system explicitly tags the asset as actively breaking. * `BLACK_SWAN` — the most extreme band, reachable from **both** the spread path (a discount beyond `2× critical`, per-asset overridable) and the CR path (hyUSD, CR \< 100%). It auto-exits via the normal hysteresis like every other band — not a no-reset terminal state (ADR-0025). `UNKNOWN` is a non-alerting status, not a severity band. On routine stale or low-confidence input the engine skips the recompute and holds the last published state rather than flipping to `UNKNOWN`; it *does* publish honest-dark `UNKNOWN` at cold-start and when an anchor is detectably broken (a >10% premium on a NAV-priced asset → the NAV-sanity gate, ADR-0025). ## Asymmetric enter and exit For an LST with a drift threshold at 30 bps: * `PEGGED → DRIFT`: the smoothed spread must cross **30 bps** and stay there for **30s**. * `DRIFT → PEGGED`: the smoothed spread must fall to **22 bps** (30 × 0.75) AND stay there for **120s**. * `DRIFT → DEPEG`: the smoothed spread must cross **100 bps** and stay there for **30s**. * `DEPEG → DRIFT`: the smoothed spread must fall to **75 bps** (100 × 0.75) AND stay there for **120s**. Notice the asymmetry. The exit threshold sits 25% below the entry threshold (`DEADBAND_PCT = 25%`). Combined with the 120-second exit dwell, this means a signal noisily oscillating in the 25–35 bps range stays in `DRIFT` for the entire duration — **one alert at entry, none in the middle, one transition back when the underlying actually heals**. ## Why the exit dwell is longer than the entry dwell Entering a stressed state is something subscribers want fast — a 30-second confirmation is plenty. Exiting back to `PEGGED` is something subscribers want to **trust** — a single tick at 29 bps after a 200 bps spike is not the same as a sustained recovery. Extending the exit dwell to 120s is a small cost (a couple extra minutes of alert state) and a big honesty win. The same logic applies at every state boundary. `CRITICAL → DEPEG` requires 120s below the critical exit threshold, and `BLACK_SWAN` decays back the same way once the spread (or hyUSD CR) genuinely recovers — it auto-exits via the normal hysteresis, not a manual operator reset (ADR-0025). ## EWMA smoothing on top of the FSM Even with asymmetric thresholds, raw ticks are too noisy. Pegana smooths the raw spread with an EWMA (exponentially-weighted moving average) using `α = 0.3` by default. That means each new tick contributes 30% to the displayed spread; the prior smoothed value carries 70%. `α` matters. A higher `α` (say 0.6) is more responsive but lets transient spikes flip state. A lower `α` (0.1) is laggy and misses real depegs. 0.3 is calibrated against 24h p99 noise per asset class — it's tight enough to catch a real depeg inside 15 seconds and loose enough that a single bad Jupiter quote doesn't trip the alert. ## What this means for downstream consumers If you're consuming Pegana's WebSocket stream as an event source — webhook trigger, prediction-market settlement, insurance payout — **you want hysteresis**. Without it, you'd see a 1-second `DRIFT → PEGGED → DRIFT` roundtrip as two separate transitions, and your downstream automation would react twice. Pegana's published transitions are guaranteed to be **sticky** for at least the exit dwell window (30s entry, 120s exit). A transition emitted at 12:34:05 means the state held for that long. You can act on the transition immediately and trust it won't reverse in the next breath. ## Reading the parameters Every threshold and dwell timer lives in `assets.toml` and is exposed via `/v1/assets//extra`. The `/thresholds ` command in `@PeganaWatchBot` returns the same numbers in chat. Reproduce the FSM yourself from raw discount ticks if you want — the parameters are open. ## Read next Full FSM parameters, formulas, exit thresholds per asset class. Higher-level overview of the five states. ### Sources * [Schmitt trigger — hysteresis in signal processing](https://en.wikipedia.org/wiki/Schmitt_trigger) * [EWMA on Wikipedia](https://en.wikipedia.org/wiki/Moving_average#Exponentially_weighted_moving_average)