About the Author
Flemming Nørnberg Larsen is a principal software developer based near Aalborg, Denmark. He works at Elsevier, where he builds and maintains software systems and has spent several years working alongside coding agents in production.
He wrote the Plain Text as Code Manifest before writing this book. The Foundation topic in this book is its application to agentic engineering.
He also built .principles, a catalog of software engineering principles as plain-text files that a coding agent reads at the start of a session. The AI already knows everything. The question is whether it knows what you care about. The book has a chapter on it.
The book grew out of the articles in the Architecture as Code example repository and out of a frustration: no good account existed of how to work with coding agents professionally. Spec-driven development is necessary. It is not enough on its own. The work also demands documentation, structure, and evidence that the coding agent did what you intended.