Components

Every component is independent — use one or all six. When you want all of them working together, reach for the RiskManager façade rather than wiring them up yourself.

RiskManager

The façade over the other six. Build it from a single RiskConfig (which carries two promoted knobs — base_risk_pct, max_notional_pct — plus a pass-through dict of keyword arguments for each component), then:

• on_equity(equity) — refresh drawdown and session state as the account moves.
• evaluate(TradeIntent(...)) — size and validate one trade, returning a RiskDecision (ok, units, stop, risk_pct, and reasons listing every gate that vetoed it, plus the full component results for auditing).
• on_fill(decision) / on_close(trade) — keep the open book and the session's streak/cooldown state current.

decision.ok is the AND of the pre-trade validator passing and the session manager permitting an entry — the latter catches behavioural blocks (tilt, cooldowns, profit target hit) that have no dedicated validator flag. The underlying components are exposed as attributes (.sizer, .drawdown, .stops, .correlation, .session, .validator) when you need to reach past the façade.

Because the manager tracks the open book, it enforces two portfolio-level caps as you trade: total open notional (max_notional_pct extended across positions) and total open heat — the capital actually at risk if every stop is hit (max_portfolio_heat_pct, off by default). Read either live with exposure_pct() / portfolio_heat_pct().

PositionSizer

Volatility-adjusted fixed-fractional sizing. You pick a base risk fraction; the sizer scales it down when volatility is above baseline, applies an optional half-Kelly ceiling, runs a reduction ladder (losing streaks, drawdown tiers, daily loss), and enforces a hard notional cap. Returns the units and every multiplier that fired.

DrawdownManager

Tracks high-water-mark drawdown and maps it onto tiers: normal → 0.75x → 0.5x → 0.25x → halt. A recovery ramp steps the tier back down one level at a time once equity recovers, and a rolling weekly-loss guard pauses new entries for 24h.

StopEngine

Each position carries a stack of stops — initial, break-even (armed at 1R), ATR trailing, EMA trailing, time, and volatility. The tightest stop relative to price is active, and stops only ever move closer. Call update() once per bar; it returns an exit reason or None.

CorrelationGuard

Allows at most one open position per correlation group. Groups can be static (you define them) or computed dynamically from a rolling return-correlation matrix (install the pandas extra).

SessionManager

Behavioural guardrails: daily trade/loss caps, profit-taking stops, minimum spacing between trades, escalating cooldowns after losing streaks, and tilt detection (shrinking hold times, size-up after losses, rapid-fire entries, weak signals).

PreTradeValidator

The composable final gate. Assemble a TradeProposal and validate() runs every rule across market quality, sizing, risk limits, signal quality, and timing — returning a pass/fail line for each and an overall veto.

Metrics

Standalone risk metrics over a return series: value_at_risk(returns, confidence) and conditional_value_at_risk(returns, confidence) (historical VaR and expected shortfall), both reported as positive loss magnitudes. Pure standard library.