It's about to become harder to spot when someone has used ChatGPT.
Sam Altman, the CEO of OpenAI, said the chatbot would no longer use the em dash — a hallmark of its writing style — if a user requested it.
"If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!" Altman said in an X post Thursday night.
Some users have complained that ChatGPT would ignore their requests to avoid the elongated dash. The punctuation is popular among writers to signal surprise or contrast — but some have stopped using it because they fear being accused of using ChatGPT.
Altman described the update as a "small-but-happy win."
Small-but-happy win:
— Sam Altman (@sama) November 14, 2025
If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!
The update comes as OpenAI continues to make ChatGPT more customizable with features like "memory" and custom GPTs. Users can ask the chatbot to remember specific details, such as formatting, and the bot will bring them into future interactions.
ChatGPT has other telltale signs, such as using clichéd phrases, but Altman did not say if there would be any updates to address those.
