--- name: principle-redesign-from-first-principles description: "Apply when integrating a new requirement into an existing design. Redesign as if the requirement had been a foundational assumption from day one, instead of bolting it on." disable-model-invocation: true --- > **Copilot host.** On VS Code or GitHub Copilot, invoke the `pstack-host` skill before any Cursor tool name, model slug, or `.cursor/` path in this file (Task, AskQuestion, /loop, subagent_type). The host skill wins. # Redesign From First Principles When integrating a change, don't bolt it onto the existing design. Redesign as if the requirement had been there from the start. - Read all affected files and understand the current design - Ask: "if we were writing this from scratch with this new requirement, what would we build?" - Propagate the change through every reference: types, docs, examples, rationale sections - Think about the whole redesign, then deliver it incrementally This is the method for preserving option value when integrating changes into an existing design.