Every instrument here is deterministic — same inputs, same output. This tool makes that auditable: it computes a real SHA-256 execution hash over the sim, its inputs, and the canon sections it cites. Change one input and the hash changes; restore it and the hash returns. That is the OpenChainGraph model in miniature: not "who owns this," but "how did this come to exist."
OpenChainGraph (OCG) treats an execution hash as a reproducible record of a transformation rather than a receipt of ownership. The primitives are execution_hash, parent_hashes, policy_parameters, and the sources a computation cites. Here the parent is the canon version (everything descends from a fixed edition of the world), the policy parameters are the sim and its inputs, and the execution hash is a SHA-256 over the ordered manifest, computed in your browser with the Web Crypto API. Nothing leaves the page.
The property that matters is reproducibility: identical inputs always yield the identical hash, so any two people who run the same instrument the same way can confirm they computed the same thing. Change a single parameter and the hash changes completely; restore it and the original hash returns. That is what lets a deterministic sim carry provenance.
This is the homepage provenance readout made interactive, and the seed of a deeper build in which every instrument emits its own execution record. See the OpenChainGraph catalogue at ainumbers.co/chaingraph and the Feasibility Audit, whose EXEC HASH box uses the same construction.