Beyond the Prompt: Spec-Driven Development and Context Engineering for AI Coding Agents

Your AI agent can build a demo. The hard part is building inside the system you already have.The first time an AI coding agent builds something real for you, it feels like magic. Then you point it at a years-old codebase with conventions, history, and other people depending on it, and the magic turns into drift: invented patterns, a second way to do everything, and bugs that surface weeks later. Beyond the Prompt is a practical methodology for that world, the brownfield systems where most software work actually happens.It brings together the two disciplines that determine whether AI-assisted coding succeeds at scale: context engineering, controlling what the agent sees, and spec-driven development, controlling what it is trying to build. You will learn to:Treat the context window as a finite resource and curate it with five repeatable movesGive the agent a durable briefing and grounded retrieval so it never works blindWrite specifications that serve at once as the agent's target, your few-shot examples, and your testsRun the full spec-driven loop, specify, plan, tasks, implement, end to end on a real featureAnchor every change to patterns your codebase already trusts, so output belongsVerify behavior and conformance, and govern the practice across a teamEvery idea is built on running examples you can clone: DataSlice, a realistic brownfield application (FastAPI + Angular) where you add a feature the book's way, plus a from-scratch greenfield example built end to end in TypeScript (Express + Angular). The complete companion codebase is included so you can build the features yourself and compare against a reference implementation.If you are past the demo stage and need AI-assisted code you can actually ship, review, and maintain, this book is the method. Read more