Paper Prototype

Hand-execute the designed process step-by-step, on real data, before any code exists. The deliverable is not working software — it is a spec delta: the spec as corrected by reality, plus the submodules and dependencies reality forced you to name.

Run in a fresh subagent (context isolation)

The validation is only honest if it works from the written spec alone. Run inline, you already carry the design conversation — assumptions, half-formed rationale, fixes you were about to make — and you'll improvise past spec gaps instead of surfacing them. That validates the spec-plus-your-head, not the spec.

So dispatch this via the Agent tool as a fresh subagent (NOT a fork — a fork inherits your context and re-leaks it). Hand it only the ## Process and ## Hard rules sections below — never this section (and never the whole SKILL.md; that would re-hand it the "dispatch a fresh subagent" line and it would recurse), plus: