Substack Launches AI Writing Detection Tool So Readers Can See How Much Is AI-Generated

Substack has introduced a new feature that allows readers to estimate how much of any newsletter on its platform was written with AI assistance. The newsletter and writing platform announced an integration with AI writing detection software Pangram this week, enabling users to scan posts, comments, and replies in the Substack app to see the estimated percentage of AI-generated content.

In the short term, the move could expose many newsletters that rely heavily on AI writing, potentially eroding trust in Substack's ecosystem of independent news and blogs. But the company is betting that long-term transparency will help keep the platform free of what it calls "AI slop" and encourage readers to trust that what they're reading was written by a person.

"This is good use of AI," Substack CEO Chris Best said during an online conversation with Pangram founder Max Spero. "When I used to pitch Substack to writers, one way I would do it is — we'll do everything for you except the hard part. You have to have something — an idea that's worth reading, that's worth caring about, that's worth sharing. That one thing is very hard and very valuable."

The detection feature works on any post, note, reply, or comment exceeding 100 characters within the Substack app. Additionally, Substack now allows writers to include an optional "AI author's note," giving creators a formal way to disclose their use of AI in the content creation process.

Substack has clarified that the tool is not designed to prohibit or penalize AI-assisted writing. Instead, it encourages writers to add a "how I make this" statement explaining their creative process. Publishers can run Pangram scans on their own drafts before publication and report or remove scans on their own work that they believe are inaccurate.

The move aligns Substack with a broader industry trend toward AI content labeling. Social media platforms already label AI-generated images and videos, and music streaming services have begun labeling and penalizing AI-generated music. Substack's addition signals that text-based content platforms are now joining this transparency movement.

While Pangram provides an estimate rather than a definitive judgment, the tool represents one of the few product-level implementations that lets consumers directly assess AI involvement in content they read. As generative AI writing tools become ubiquitous, the tension between creative efficiency and authenticity will only intensify — and Substack's transparency-first approach may set a precedent for the wider content industry.