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@@ -104,6 +104,7 @@ Skills are organized by domain under `skills/`. Each skill is a folder with a `S
 - [`refactor-roadmap`](skills/planning/refactor-roadmap/SKILL.md): Sequence refactors with tests, flags, and checkpoints.
 - [`tech-debt-portfolio`](skills/planning/tech-debt-portfolio/SKILL.md): Catalog debt, estimate impact, and prioritize with ROI.
 - [`roadmap-prioritization`](skills/planning/roadmap-prioritization/SKILL.md): Score initiatives by impact, effort, and dependencies.
+- [`before-you-build`](skills/planning/before-you-build/SKILL.md): Pressure-test a product idea or feature before implementation by identifying the biggest demand, positioning, monetization, retention, and distribution risks.
 - [`org-standardization`](skills/planning/org-standardization/SKILL.md): Propose minimal standards and adoption enforcement.
 - [`vendor-evaluation`](skills/planning/vendor-evaluation/SKILL.md): Compare vendors by security, integration, cost, and risks.
 - [`dependency-upgrade-plan`](skills/planning/dependency-upgrade-plan/SKILL.md): Order upgrades, note breaking changes, and plan rollback.
diff --git a/skills/planning/before-you-build/SKILL.md b/skills/planning/before-you-build/SKILL.md
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+---
+name: before-you-build
+description: Review a product idea or feature before implementation by identifying the biggest demand, positioning, monetization, retention, and distribution risks. Use when a senior developer or founder wants to build a new product, landing page, MVP, or major feature but needs a reality check first.
+---
+
+# Before You Build
+
+## Purpose
+Pressure-test a product idea or feature before implementation starts.
+
+## Inputs to request
+- Who the product or feature is for.
+- The concrete situation where they would use it.
+- The painful problem it solves.
+- How people solve the problem today.
+- Any existing signals: users, conversations, waitlists, revenue, usage, churn, or competitor evidence.
+
+## Workflow
+1. Restate the idea in one plain sentence.
+2. Identify the riskiest assumption that would make the project fail if false.
+3. Check demand, distribution, willingness to pay, positioning, retention, and trust risks.
+4. Separate weak evidence from stronger evidence.
+5. Recommend the smallest next validation step before building.
+
+## Output
+- Short verdict: build, validate first, narrow the scope, or stop.
+- Biggest risk with rationale.
+- Evidence gaps.
+- Specific next validation action.
+- Optional kill criteria that would stop the project.
+
+## Quality bar
+- Do not recommend tech stacks, architecture, or implementation details.
+- Be direct and concrete, not motivational.
+- Prefer one sharp risk over a long generic checklist.
+- If the idea is too broad, ask who it is for, when they use it, and what painful problem it replaces.