Article URL: https://blog.lyc8503.net/en/post/llm-classifier/ Comments URL: https://news.ycombinator.com/item?id=48936880 Points: 33 # Comments: 9

This article is currently an experimental machine translation and may contain errors. If anything is unclear, please refer to the original Chinese version. I am continuously working to improve the translation. As of early 2026, mainstream LLM-generated text exhibits strong statistical patterns that can be effectively distinguished from human-written content using traditional machine learning models. I suspect this is how many so-called “AI plagiarism checkers” actually work under the hood. The model used in this demo is not trained on general-purpose data, nor has it undergone rigorous optimization or iteration. Its single-sentence detection accuracy is approximately 85% on the test set. Please read through this article before use to understand potential limitations. The core code (drafts) and trained model files are available on GitHub: lyc8503/AITextDetector Back when I was still writing my thesis at school half a year ago, rumors were already spreading about checking papers for AIGC (AI-generated content). I tested several platforms—CNKI, Wanfang, and some third-party AIGC detection services—and found they could indeed distinguish between my hand-written text and LLM-generated text with decent accuracy. That sparked my curiosity about how AIGC detection actually works(and how to bypass it). But I was juggling too many things at the time—obsessed with radio, Minecraft, Touhou—and after a few failed attempts, I shelved the idea. Eventually, I faked my way through the thesis, and life moved on. But recently, while browsing Lofter, I stumbled upon entire tags flooded with low-quality, wildly out-of-character AI-generated fanfics.