The Agentic Substrate: WebMCP and the Structural Transformation of the Web

The Agentic Substrate defines the moment the web ceases to be a navigational institution and becomes an execution substrate. It situates WebMCP (Web Machine‑Callable Protocol) as the inflection point where callable functions replace hyperlinks, and agents replace users as the primary operators of the web. Through the SignalRupture (SR) framework, the paper traces how this architectural shift reconfigures cognition, authority, and institutional legibility. It demonstrates that WebMCP is not a technical upgrade but a substrate transformation — a structural reorganization of the web’s epistemic architecture that accelerates cognitive drift, institutional drift, and operational opacity. The analysis positions WebMCP within the genealogy of infrastructural transitions, showing how execution supplants exploration and how efficiency becomes the mechanism of epistemic collapse.