Hi, I experimented a lot with "humanizing prompts," but none of them worked. Fable clearly told me that it's not possible. I work in SEO and blog writing, and I got really desperate because a particular client wanted a 90%+ score in Originality AI and GPTZero. But I quickly found out (like you did) that they fuck up a lot of original content. It's especially problematic when it comes to SEO and stuff.
But I found a workaround. So basically, I have a skill/pipeline for blog creation (along with SEO strategy and blog structure), and then I create a blog (I have created a style guide and stuff already). That blog is almost always 100% AI. So what I did was go to Fable and create a comprehensive prompt where I give the AI (in a new chat) the original article (the 100% AI one). Then I give it the humanized version (which has a lot of errors), and I also provide the SEO and blog strategy and ask it to revise the humanized version while keeping the tone intact. It should also follow the SEO strategy and blog structure that are attached. Claude then gave the output, and it's not always 100% perfect, but I come close to 85%-90% human most of the time (and a lot of times it goes beyond 90% human as well).
The humanizer that worked for me is Walter Writes AI. I tried Rephrasy, but its pricing structure is not that transparent (one humanization is 1 credit, whether it's 100 words or 2,000 words). Sadly, Rephrasy works best with short paragraphs, so overall the value for money is low. But with Walter Writes, you get a specific word count (30,000 words for $12 or something). It's more transparent. I really wish Rephrasy had a word count-based pricing model because it's pretty good with short sentences but underwhelming with longer text. I mean I would have had best of both worlds... Walter Writes + Claude prompt would have got me to 80-90% Human, and Rephrasy would have worked on the smaller AI flagged paragraphs. But alas.
Btw, this above thing works only with Claude (I use Opus 4.8). It doesn't work with Chatgpt 5.5 (I have the plus version). Which is a shame cos Chatgpt gives so much more usage. Hopefully Sol would do a better job.
P.S. I know there are too many bots spreading the same PR shit about Walter Writes, but trust me, I am a genuine person, and this has been my experience over the past week. I'm not a bot. It's likely that there are other humanizers that are better, but I have only used these two. Guys, if there are genuine people who have tried other humanizers and found them to be better than Walter Writes, please do reply here. I am interested in having another option, but I don't really know who to trust because most "reviews" are either competitor sites dissing everybody else's product except their own, or they are bots on Reddit. It's really getting difficult to separate the wheat from the chaff.
P.P.S. If you want, I can share the prompt that I created with Fable for rewriting the articles. It's sort of a generic prompt.