Prose Writer is a chainable TypeScript library for building formatted text and Markdown. It is useful for prompts, generated documents, and anywhere else that a growing collection of string fragments starts looking suspiciously like a formatting system with no rules.

The API keeps that structure explicit: add prose, headings, lists, and other blocks in order, then render the result as a string. The goal is not to invent another document format. It is to make the format you already need easier to assemble, inspect, and change.