Jean The Writer
Yannick L.
Published
AI-Powered Manuscript Correction & Editorial Review
In early 2025, I built Jean The Writer, an AI-powered backend tool designed to help writers turn raw drafts into polished, publication-ready manuscripts. The project began with a unique request: correcting a 600-page French manuscript written entirely without punctuation. What started as a one-off challenge quickly evolved into a scalable system for independent writers.
Project Overview
Jean The Writer automates grammar and syntax correction, delivers chapter-by-chapter editorial reviews, and compiles clean Google Docs output with professional formatting. Unlike generic writing assistants, it’s built for long-form manuscripts, handling large texts in blocks, ensuring stylistic continuity, and even suggesting publishers. For authors, this means saving weeks of manual editing and reducing costly editorial fees, all while keeping their voice intact.
My Role
This was a solo build, and I owned the full cycle:
Product Strategy → Designed the workflow around a client’s needs (correction, review, publisher search).
Architecture & AI Workflows → Built modular processes with Chain of Thoughts logic and resume-capable scripts.
AI Engineering → Selected the best LLMs (GPT-4o mini for correction/review, OpenAI Deep Search for publishers).
Automation & Delivery → Integrated with Google Docs API for formatting (Times New Roman, 12pt, 1.5 spacing) and optional diff highlighting.
Stack & Tools:
Node.js, TypeScript, OpenAI API, Google Docs/Drive APIs, diff-match-patch, Jest, Prettier, ESLint.
Outcomes
Successfully processed 8 manuscripts (French & Spanish).
First commission: a 600-page punctuation-free novel, corrected and reviewed.
Authors praised the corrections and publisher recommendations, though editorial feedback sometimes met resistance, a valuable reminder that style is deeply personal.
What I Learned
Jean The Writer reinforced my skills as both developer and product builder. I mastered AI workflows for edge cases, advanced prompt engineering at scale, and strengthened integrations with OpenAI and Google APIs. Most importantly, I learned that AI’s role in writing isn’t to replace creativity, but to empower it, automating the repetitive so authors can focus on storytelling.