This repository hosts the Software Carbon Intensity (SCI) specification, a standardized methodology for measuring and reporting the carbon emissions of software systems as a rate (emissions per functional unit). The core artifact is SPEC.md, which defines the SCI calculation framework including formulas for operational and embodied emissions, guidance on system boundaries and functional units, and quantification methods. The repository also includes a static website (generated from SPEC.md) that presents the specification, an example case study demonstrating application of the methodology to a real web application (eShoppen), and automation for building and deploying the site. While the repository does not process data or implement the SCI calculation itself, it provides a complete, reusable framework for software carbon measurement that defines how to collect, transform, and interpret emissions data.