Guide for advanced Next.js App Router patterns including Route Handlers, Parallel Routes, Intercepting Routes, Server Actions, error boundaries, draft mode, and streaming with Suspense. CRITICAL for server actions (action.ts, actions.ts files, 'use server' directive), setting cookies from client components, and form handling. Use when requirements involve server actions, form submissions, cookies, mutations, API routes, `route.ts`, parallel routes, intercepting routes, or streaming. Essential for separating server actions from client components.

Pattern for client components calling server actions to set cookies in Next.js. Covers the two-file pattern of a client component with user interaction (onClick, form submission) that calls a server action to modify cookies. Use when building features like authentication, preferences, or session management where client-side triggers need to set/modify server-side cookies.

Pattern for using useSearchParams hook with Suspense boundary in Next.js. Covers the required combination of 'use client' directive and Suspense wrapper when accessing URL query parameters in client components. Use when building search interfaces, filters, pagination, or any feature that needs to read/manipulate URL query parameters client-side.

Guide for Vercel AI SDK v5 implementation patterns including generateText, streamText, useChat hook, tool calling, embeddings, and MCP integration. Use when implementing AI chat interfaces, streaming responses, tool/function calling, text embeddings, or working with convertToModelMessages and toUIMessageStreamResponse. Activates for AI SDK integration, useChat hook usage, message streaming, or tool calling tasks.