Substack's new tool tells you who's been writing their newsletters with AI | TechCrunchtechcrunch.comSubstack is giving readers a way to estimate how much of a newsletter was written by AI, signaling a broader shift toward transparency around AI-assisted content.Substack's new tool tells you who's been writing their newsletters with AI | TechCrunchtechcrunch.comSubstack is giving readers a way to estimate how much of a newsletter was written by AI, signaling a broader shift toward transparency around AI-assisted content.