This is a TypeScript library providing a builder API for typesafe Next.js server actions with Zod validation. It is structured as a monorepo with core package `zsa`, React hooks (`zsa-react`), React Query integration (`zsa-react-query`), and OpenAPI exposure (`zsa-openapi`). The core library supports input validation (JSON, FormData, useActionState), procedures for middleware chaining with context propagation, typed error handling via `ZSAError`, configurable retries and timeouts, and client-side hooks (`useServerAction`, `useActionState`). The OpenAPI module generates REST endpoints and OpenAPI specifications from server actions. The codebase is well-organized with fluent builder patterns, comprehensive test coverage (Jest + Playwright), and a documentation site using Fumadocs. However, it is a personal project currently lacking support for Next.js 15, and all packages are pre-1.0 (0.x), indicating potential instability and limited maintenance commitment.