Spec-Driven Development: From Specs to Code with AI Agents

Start your development process with a blueprint. Most teams jump into coding and leave documentation for later, if at all. Too often this leads to maintenance issues, stalled modernization, and poor business alignment. Spec-driven development flips the order: the specification becomes the single source of truth that drives code, tests, and validation. This pocket guide introduces the AI Unified Process, a lightweight framework that makes Spec-driven development practical in the age of generative AI. It shows how specs (requirements, use cases, entity models) can act as contracts, enabling AI agents and modern tools to generate, validate, and evolve software with far less guesswork. Designed for busy teams, this book focuses on the principles of spec-first development, with AI Unified Process skills and templates as the primary enabler. It also introduces emerging tools like Amazon Kiro and GitHub Spec Kit for context. Alongside practical methodology, you'll work through a hands-on case study that takes you from requirements to executable code. By the end, you'll understand how to apply Spec-driven Development in practice, avoid common pitfalls, and integrate AI into a disciplined, scalable workflow.

What You Will Learn

• Capture requirements in lightweight specs
• Treat specs as executable contracts for code generation and testing
• Apply the AI Unified Process to projects and team workflows
• Integrate AI agents into a spec-driven lifecyce

Who this Book is for:
Software developers, tech leads, and architects with basic programming knowledge. No prior experience with requirements engineering or AI tools is required.

Author: Simon Martinelli
Publisher: Apress
Published: 08/13/2026
Pages: 152
Binding Type: Paperback
Weight: 0.57lbs
Size: 9.21h x 6.14w x 0.38d
ISBN13: 9798868828508
BISAC Categories:
- Computers | Programming | General
- Computers | Artificial Intelligence | General

About the Author

Simon Martinelli is a Java Champion, Vaadin Champion, and Oracle ACE Pro with over three decades of experience as a software architect, developer, consultant, and trainer. He is the creator of the AI Unified Process and a strong advocate of Spec-Driven Development.
As the owner of Martinelli LLC, he coaches teams to get up to speed with AI-driven development. He regularly shares his insights through international conferences, articles, and his blog, Keep IT Simple, where he writes about AI, architecture, and modern Java development.
He is also a lecturer at two universities in Switzerland, where he teaches software architecture, persistence, DevOps, and cloud-native development.