AI coding agents read constraint documents before they write code. Claude Code reads CLAUDE.md. Block's Goose reads agents.md. Both are now Linux Foundation projects under the Agentic AI Foundation. I ran Kubernetes infrastructure builds with progressively detailed spec files and measured the difference. A prompt with no spec produced scattered output needing constant human intervention. A structured spec with build phases, dependency maps, and completion gates produced significantly better results. This talk introduces spec authorship as a cloud native engineering practice. These files belong in your repo alongside ADRs, Helm values, and Kyverno policies. Five real spec files are Apache 2.0 on GitHub.