SemVer-Trust

ADR-004 — Derivation proofs are the only exception to weakest-link flooring

Status: Superseded by ADR-033 (2026-07-13) Date: 2026-07-04 Decision: outputs byte-identical under a re-run of a pinned derivation command inherit the minimum trust of the declared inputs. Toolchain version is itself an input. Formatting-only commits are a degenerate derivation. Rationale: generalizes the original OpenAPI/oapi-codegen insight (Brad’s starter-repo philosophy: specs as human-reviewed contracts, generated code as constraint) to protoc, lockfiles, codemods, formatters — satisfying Requirement 1 without weakening P3, because the exception is verified by reproduction, not declared. Notably, this is a novel and defensible argument for spec-first architecture in the AI era: a reviewed contract extends its trust to everything provably generated from it. Rejected: path-based exemptions for gen/** directories without regeneration (declared, not proven); size/type-based triviality exemptions (P3 corollary).