The **ses‑shim** repository provides the core “Secure ECMAScript” (SES) implementation used by Agoric’s Endo framework—a hardened JavaScript runtime that locks down the language, hardens objects, and creates isolated compartments. It is intended for developers building security‑critical JavaScript applications—such as plugin platforms, smart‑contract environments, or distributed systems—that need strong containment, least‑authority guarantees, and safe capability‑based communication.