duhem

Author Duhem Verification Definitions (criteria + checks YAML) for features under verification. Use when asked to "write a verification", "spec acceptance criteria", "author checks", "verify this feature", "translate criteria to checks", "write criteria", "draft a Verification Definition", or when a Duhem product-surface spec needs a worked example, or when adding a Verification Definition to dogfood a feature on onsager-ai/onsager. Enforces Duhem's Holistic Verification Principle (no mocks of the web), the criteria-vs-checks separation (criteria stable, checks derivative), and the mechanical-judgment rule (no LLM-in-the-loop verdicts).

The end-to-end spec-issue-driven dev loop for Duhem — spec → branch → implement → PR → merge → closure. Use when asked "how do I start work", "what's the process", "SDD loop", "spec-driven development", "how do we ship a change on Duhem", "from scratch what do I do", or when you're about to begin a non-trivial change on the Duhem repo and haven't yet decided how to split spec/PR. Delegates to `issue-spec` (spec writing), the global `pre-push` (pre-push checks) and `pr-lifecycle` (post-push) skills, `verification-authoring` (authoring Verification Definitions for the platform itself), and `onsager-dogfood` (running Duhem against the Onsager repo). This skill carries Duhem's overlay for `pre-push` / `pr-lifecycle` — the check gate, merge-collision patterns, and CI-failure table.

Dogfood Duhem against the products it verifies (Onsager, Chreode, Crawlab) — Duhem-as-tool with co-located `.duhem/` VDs. Use when authoring or maintaining a product's Verification Definitions, when wiring a product self-gate (Mode A) or Duhem's drift-monitoring lane (Mode B), when triaging a verdict that fired on a product PR, or when you're unsure which side of the Duhem/product seam owns a change. Covers the cross-repo discipline (which spec lives where, which PR opens where), the trust model (mechanical judgment + a self-verified Duhem contract + optional CODEOWNERS/hub — not hoarded checks), and `docs/duhem-spec.md` §10.1 Pattern D / Appendix D / §14. Triggers include "dogfood on Onsager", "dogfood on Chreode", "verify against a product", "product PR check", "drift monitoring", "co-locate VDs", "cross-repo spec", "which repo owns this", "Duhem/product boundary".