How I Orchestrate 7 AI Agents in a Single Next.js App (With Code)

Most "AI agent" posts are theory. This one has code. I built Cresva, an AI marketing platform with 7 specialized agents that pull data from Meta, Google Ads, GA4, and Shopify, analyze it, and deliver insights autonomously. One Next.js app. One developer. No microservices. Here's how the orchestration actually works. The Problem With Single-Agent Systems If you've built an AI wrapper, you've hit this wall: one LLM call can't do everything well. Ask GPT-4 to pull data AND analyze it AND generate strategy AND format a report in one prompt? You get mediocre output across the board. The fix: specialized agents with typed contracts between them. Each agent in Cresva has one job: type Agent = { id : string ; role : ' data_engineer ' | ' performance_analyst ' | ' media_strategist ' | ' attribution_analyst ' | ' creative_strategist ' | ' marketing_ops ' | ' account_manager ' ; execute : ( input : AgentInput ) => Promise < AgentOutput > ; validate : ( output : AgentOutput ) => ValidationResult ;