content-negotiation-for-agents-skill

Adds HTTP content negotiation to a Next.js app so AI agents fetching a page get clean Markdown (via the Accept header) while browsers get normal HTML from the same URL. Use when a Next.js developer wants to make a blog, docs, changelog, help center, or knowledge base "agent-readable", "AI-friendly", "readable by AI agents / LLMs", to "serve text/markdown", add an "llms.txt" or Markdown sitemaps, or implement "Accept header content negotiation". Covers Next.js App Router (server-rendered) and static export (output: 'export'). It ALWAYS asks which pages to target before changing anything, and verifies the result with a live HTTP request before reporting done. Next.js only — if the project is a different framework, it says so rather than guessing.