Let the heat turn the regime

Make the chain's two transition rates depend on the heat, for example wake = wake_0 * exp(k * C), so a market that runs hot is likelier to turn active and slower to calm. Keep the mean pace at one over the long run, which now depends on the heat's own mean. A third, panic state is its own capture; the coupling here would apply to its transitions too.

Gemini's review drew heat thresholds that switch the state, and a third volatile burst state. A threshold is the wrong mechanism, because a state that flips at a number flaps around it. The need behind it is real: today the chain is exogenous, so a burst of activity can never cause a calm market to turn, and a panic cannot feed on itself through the regime.

It changes the market's model, so it needs the same care as the tails: a stated rule, a test that the long-run pace still holds, and a note in the market volatility channel page.

• Gemini's review of the Market regime tab
• The market's volatility channel
• Make activity and volatility excite each other

• Add a panic state to the regime — the third state, which this would drive as well.
• Carry a market-wide arrival regime — the story that built the market these extend.