For the Head of Exposure Management
The storm is already moving, and finding out what it does to the book must not change the book.
The models that answer the first half of that live somewhere other than the systems holding the book, so the answer arrives as a spreadsheet, hours late, from a person. Anything faster usually means somebody wrote a scenario into a real table — and now a number in a real report is a guess nobody labelled.
Everything a scenario touches carries the quarantine with it
That band is the product’s own component, rendered here rather than drawn. It is on a public marketing page for the same reason it is in the console: a screenshot of any fragment of a simulated surface has to say so on its face, and a banner that can be dismissed, timed out or cropped away fails that the first time it matters. No run stands behind this page — which is why it reads no scenario, no seed and no ticks, and why its exit control has nothing to return you to.
Modelled impact on the bookSimulated — not live
Those are placeholders, and they are placeholders on purpose. The catastrophe financial chain that would produce a euro figure — the exposure object, the vulnerability and damage curves, deductible and limit application, exceedance-probability curves and the stochastic event catalogue — is not built. Printing a plausible number here would be the exact defect this site exists to argue against, so the figure stays [P: to be calibrated] until an engine we have written produces it.
REVERSIBLE IN ONE TRANSACTION
Every simulated value is written with a simulation flag and lives in an overlay above live state rather than inside it. Exiting restores the live view in a single transaction, and a simulated value cannot enter a certificate, a sealed record or an export unless the marker travels with it. Purple appears nowhere else in the product, ever.
FEEDS ARE OBSERVATIONS, NOT SETTLEMENT INDEXES
The public hazard feeds behind a scenario are treated as observations of the world. They are not treated as an index that settles a contract, and a decision derived from one still passes the gate and still needs a named human. A dead feed declares itself and flags the decisions that depended on it rather than quietly serving stale values.
[O] Illustrative composition, built from the components the product ships. No customer data appears anywhere on this site. The peril simulators, the live feeds and the reversible overlay are observed at SOV/services/nexus-disaster-engine/src/lib.rs, SOV/services/nexus-sim-schema/src/lib.rs and SOV/services/synergy-server/src/handlers/sim_proxy.rs.
The mechanism, in three lines
Simulation runs inside the decision moment and never contaminates live state — every simulated value is quarantined, marked, and reversible in one transaction.
First
The scenario runs beside the decision
Hazard is scored per location inside the moment someone is deciding, rather than in a separate tool whose output arrives after the decision has been made.
Then
Every simulated value is marked
Simulated values are flagged at the point they are produced, so the marking travels with them into every panel, export and record. Nothing has to remember to add it later.
Finally
Leaving is one transaction
Exiting the scenario restores live state in a single reversal. A what-if that cannot be un-done is not a what-if; it is an edit nobody approved.
designed, not built(designed, not built)The engines and the quarantine are deployed. What is missing is the money — and the seam that lets the orchestrator drive the simulator. Both are named below.
SOV/services/nexus-disaster-engine/src/lib.rs, with its simulator and feed modules; the feed sources are the public hurricane, seismic, emergency-management, active-fire and volcanic-ash services those modules read. “Zero live records mutated” is a property of the overlay: simulated values are written with a simulation flag above live state, at SOV/services/nexus-sim-schema/src/lib.rs, and the reversal is the single transaction that drops the overlay. None of these is a customer measurement — we have no customers yet — and none of them is a loss figure, because the chain that would produce a loss figure is not written.The honest limit
WHAT THIS DOES NOT DO YET
- The catastrophe financial chain — the exposure object, vulnerability and damage curves, deductible and limit application, exceedance-probability curves and any stochastic event catalogue. What exists is peril physics and the analytics shell, not a catastrophe model.
- The UNO→simulator dispatch seam. The simulator is deployed and the orchestrator is deployed; the executor that lets one drive the other does not yet do so.