workflow-fix: artifact-reuse fitness check gains pairwise provenance-coherence item (j)

Overview / Motivation

Auto-filed by the workflow-fix-on-bug protocol from a workflow-fix candidate raised on task #922 (emitting agent: experiment-implementer, crash-fix round 4).

Goal

Add a pairwise provenance-coherence item (j) to the artifact-reuse (a)-(i) fitness check: for any reused artifact PAIR that must be mutually consistent, compare HF last-commit dates + reconstruction/regeneration metadata and REVISE when a consumed input postdates its dependent capture.

Workflow gap

• Bug observed: #922's plan sha-pinned #779's question artifacts + cx.pt and passed every reuse-fitness check, but the questions had been REGENERATED after the activation capture (documented in the artifact's own reconstruction field, HF commit 9578892ef4 2026-07-02 vs capture a8060198a4 2026-07-01) — the pair was mutually inconsistent and the run crashed at the parity assert after a full GCE cycle (att-20260703-163130).
• Why it is a workflow gap: the reuse checklist's content-identity check (f) pins each artifact's CURRENT bytes but never checks PROVENANCE COHERENCE across a mutually-dependent artifact PAIR (an input regenerated AFTER a dependent capture); the existing "Pinned artifact pairs can disagree" memory covers coverage mismatch, not post-hoc regeneration.
• Confidence (emitter): high

Proposed change (candidate diff sketch — refine in planning)

• (j) Pairwise provenance coherence. When reuse consumes an artifact PAIR that

• must be mutually consistent (question/prompt banks vs activations captured
  

• under them; training mixes vs adapters), verify the input does NOT postdate
  

• the dependent capture: `HfApi.get_paths_info(..., expand=True)` last-commit
  

• dates + any `reconstruction`/regeneration metadata field. A consumed input
  

• regenerated AFTER the capture is inconsistent regardless of sha pins
  

• (#922 att-20260703-163130).
  

Scope / surfaces

• Primary target: .claude/rules/artifact-reuse.md
• Grep the workflow surface for enforcement hooks before editing (grep -rln 'fitness check' .claude/ CLAUDE.md) — the (a)-(i) letter set is referenced from CLAUDE.md, planner.md step 5, consistency-checker, critic.md Methodology item 9; extending to (a)-(j) must update every referencing surface. Also consider a matching .claude/rules/gotchas.md bullet (the r4 failure-lesson flagged gotcha_candidate: yes — fold it here rather than a second task).

Constraints / invariants

• Workflow-surface only; workflow_lint.py passes.
• This session runs under EPM_WORKFLOW_FIX_SESSION=1 and carries a workflow_fix_target: Provenance line — recursion guard applies.

Provenance

• workflow_fix_target: .claude/rules/artifact-reuse.md
• fingerprint: 5d3f86e1b463

Verbatim candidate block from the #922 r4 implementer report (see epm:experiment-implementation v4 / the r4 return text).