The advent of large language model-based writing tools have given lazy or unconfident writers incredible new shortcuts that can spit out everything from glossy work emails to crispy school papers.

The problem, of course, is that bosses and teachers around the world quickly got wise to the phenomenon — and as a result, any text that feels too tidy and polished has started to arouse suspicion.

Now, in an effort to reintroduce some of the messiness of human writing — and hide our AI addiction — venture capitalist Ben Horwitz used Anthropic’s Claude AI to vibe code a browser plugin that does something that would have seemed preposterous just a few years ago: intentionally adding typos to emails.

“I made the anti-Grammarly,” he bragged, referring to a popular, AI-powered spelling and grammar checker. “Mess up your emails with AI.”

The cleverly named software, dubbed “Sinceerly,” promises to wreak some controlled havoc on overly coiffed emails, from undoing capitalization at the beginning of a sentence to the introduction of glaring typos that would make any copy editor’s eye twitch. (We’d advise against trying it out yourself until you get to the caveat at the end of this piece, though.)

You can even choose the degree of severity for the errors, ranging from “Subtle,” to “CEO,” a tongue-in-cheek jab at high-ranking executives who are known for how little care they put into their communications. It’ll even go as far as to append the phrase “sent from my iPhone.”

The browser plugin was inspired by our growing obsession with often-overbearing spellcheckers.

“I am a terrible typist, naturally, and lightly dyslexic,” Horwitz told Business Insider’s Katie Notopoulos. “It would take me so long in my first job straight out of college to write emails and make sure there were no typos and everything.”

“When Grammarly came around, it was like, ‘Oh, OK, this is pretty good for me.’ But now my email inbox is filled with AI slop,” he added.

“I tested Sinceerly by cold emailing 5 Fortune 500 CEOs,” Horwitz bragged in a Thursday tweet. “Four replied. Of those replies, each was under ten words. Two replies had typos.”

In Notopoulos’ testing, the tool turned a polite email draft informing her boss that she’s hoping “to have a sandwich for lunch today” into a messier “writing to confirm lunch plans” when shifted into “CEO” mode.

However, in our own testing, the vibe-coded project appears to have succumbed to bugs after BI published its piece, with an error message rendering it largely useless. In other words, for now, you’re stuck relying on your own human flaws for less AI-sounding work emails.

More on spellcheckers: CEO Confronted Over Using AI to Clone Real People Without Their Consent