ts‑patch is a tool that patches the TypeScript compiler to let developers add custom transformers (plugins) directly via `tsconfig.json` or programmatically. It works both as a “live” in‑memory compiler (invoked with `tspc` or via the `ts-patch/compiler` entry points) and as a persistent patch for the core TypeScript files, enabling source‑file and whole‑program transformations, diagnostics tweaks, and ES‑module plugins—primarily for TypeScript 6+ projects that need compile‑time code manipulation.