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:ID:       0b5a8a74-cfd6-542d-bc88-4eb3cd8626f9
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#+title: Cost Structure — Zero Marginal Cost
#+filetags: :passepartout:economics:cost:marginal:zero:

- **One-time cost:** [[file:gate-rule-encoding.org][gate-rule encoding]] for a domain (from hours for codified domains up to months for tacit domains)
- **Near-zero marginal cost:** ACL2 proof + Screamer consistency check + VivaceGraph lookup per interaction — all CPU-native, all in-image
- **No recurring LLM API costs** for the 80% symbolic reasoning layer
- **After [[file:sufficiency-flip.org][sufficiency flip]]:** pennies per day vs dollars per day for LLM-only

The cost curve inverts: generation is expensive, verification is cheap. This is the inversion Passepartout exploits. This is the core insight of [[file:lisp-economics.org][Lisp economics]] — symbolic verification costs approach zero while LLM token costs remain constant.

Token demand shifts from "every interaction burns tokens" to "only unfamiliar interactions burn tokens." Steady-state per-user LLM consumption drops by an order of magnitude.