# demon-dy > Open-source publisher. Listings imported from github.com/demon-dy — credited to the original author with their license. - **Listings:** 2 - **Total installs:** 0 - **Profile:** https://agentstack.voostack.com/s/demon-dy - **Website:** https://github.com/demon-dy ## Published listings - [Product Stagegate](https://agentstack.voostack.com/l/skill-demon-dy-product-methodology-skills-product-stagegate) — Skill · Free · security-reviewed — `agentstack add skill-demon-dy-product-methodology-skills-product-stagegate` Use when someone is building or running a new product (C-end or small-B SaaS, 0→1 / 1→10) and needs to know which stage it is at, whether it has passed the current gate, or what to do next. Symptoms include "should I start advertising / scaling now", "users love it on first try — is this PMF", "DAU is growing so we're good", "我做了访谈接下来做什么", confusing activation with retention, jumping stages, judg… - [True Demand](https://agentstack.voostack.com/l/skill-demon-dy-product-methodology-skills-true-demand) — Skill · Free · security-reviewed — `agentstack add skill-demon-dy-product-methodology-skills-true-demand` Use when a user is working through a product idea, demand/market research, an MVP, a "nobody buys / nobody uses / nobody renews" problem, willingness-to-pay, pricing, go-to-market, stakeholder buy-in, an internal innovation project, a business-model question, or a post-mortem — and they have NOT pre-classified what kind of problem it is. Diagnoses whether the bottleneck is value, consensus, mode,… --- Seller on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Install any with `agentstack add `.