Validation Ownership

Shared validation owns reusable invariants for consolidated seams.

Rules: - Shared validation decides canonical pass/fail for reusable input invariants. - Workflow-local code may do convenience preprocessing before validation. - Workflow-local checks stay local only when they are specific to execution or output handling. - strict=True escalates shared warnings to failures. - strict=False preserves warnings as observable issues, but workflows must not reinterpret shared invariants. - Shared validation is also the canonical source for human-readable schema metadata used by CLI help and onboarding requirement tables. - Non-DataFrame governance and workflow metadata validation belongs in src/cranalytics/governance_models.py; it must not replace Pandera or workflow contract seams for tabular inputs.

Applied seams: - Loan history: loan_history_contract.py - Loan snapshot: loan_snapshot_contract.py - Rollforward: rollforward_contract.py - Predictive: predictive_contract.py - Vintage: vintage_contract.py

Examples of shared invariants: - required columns and alias resolution - target leakage checks - binary-target shape checks - missing split periods - selected-vintage structural validity

Examples of workflow-local checks: - output/artifact handling - CLI flag combinations - ranking and promotion logic - rendering shared schema metadata into workflow-specific prose or starter templates