Omission-Safe Conditional Contracts for Evidence-Closed CI Qualification

Continuous-integration evidence is conditional: a workflow determines which jobs should run, while an archive records which jobs remain observable. Reconstructing requirements from those observations lets an omission erase its own obligation. We present a qualification method that compiles a pinned workflow into conditional job requirements independently of target presence, retains a fixed capture inventory, and checks source-complete derivation certificates with a separate implementation. For a fixed source, context, scope and binding universe, with sound obligations and applicability judgments that preserve established truth under information extension, withdrawing observation facts cannot create authorization. The implementation handles static matrices, dependency guards and bounded pinned reusable workflows, preserving unknown applicability and separating tolerated outcomes from evidence coverage. Both implementations match the 45 hand-specified authorization controls, reject 180 source-certificate attacks, and exhibit no authorization gain over 704 distinct proper development erasures. An explicitly witnessed 12-job platform run qualifies in both implementations; all 4,095 proper payload-subset erasures block authorization. A frozen collection spans 240 runs in eight workflow families across six projects. All 160 evaluation source certificates independently validate, but unavailable historical execution-source identities leave actual qualification open. Initial gate diagnoses agree on 155/160 runs; a preserved unknown-propagation repair yields 160/160 agreement in a retrospective rerun. The study establishes bounded source extraction and omission resistance, rather than natural-fault prevalence or producer authenticity.