Medium launches TK, a writing notebook app with an AI helper you call up mid-sentence
Writers type “@TK” to ask a question or pull in old notes without leaving the page. Medium says no AI company trains on what users write.
Medium, the online publishing site where people post articles and blogs, released a writing notebook app called TK on Nov. 9, according to a post by CEO Tony Stubblebine on the company’s blog. Anyone with a Medium account can join, he wrote.
What Medium is
Medium is a website and app where anyone can publish articles without first building a mailing list or a following. More than 100 million people read and share writing there each month, and the company is paid for by more than a million members who subscribe, not by ads or selling data, its About page says. Its writers include software developers, amateur novelists, product designers and CEOs, the company says.
What TK means and who it’s for
TK isn’t really an acronym. It is an old newsroom and publishing mark meaning “to come,” left in a draft where a fact or paragraph still needs to be filled in. Stubblebine wrote that those placeholders often led writers to stop and go look things up, so the app lets them handle a “TK” without leaving the page.
The app is meant for people who “write to think,” not for churning out AI-written articles, Stubblebine wrote. It comes with shared spaces for daily journaling, for getting feedback on early drafts and for turning notes into a self-published book. “TK is the gym and Medium is the stage,” he wrote, meaning TK is where people practice and collect ideas in private, and Medium is where they publish and can get paid.
What it does
Most AI writing help today happens in a separate chatbot window, such as ChatGPT, or in a side panel. TK puts the assistant inside the page. A writer types “@TK” followed by a request, such as asking whether September has 30 or 31 days, or pulling in a paragraph written the day before.
The app includes AI feedback on drafts and headlines, daily writing prompts and summaries that group old notes by theme. Writers can also share drafts in small groups for feedback from people. It imports notes from apps such as Bear and Obsidian, and exports plain text files.
AI questions
Stubblebine wrote that no AI company trains on users’ writing without permission. Notes can be published with labels showing which parts a person wrote and which the AI wrote, an answer to worries about hidden AI text online. TK can also connect to a user’s own AI agent, such as Anthropic’s Claude, through a standard plug-in link, so the agent can read the writer’s notes. There is no desktop app yet. Medium says it has been profitable since August 2024.
Source: Medium blog post by Tony Stubblebine, Nov. 9, 2026 and Medium’s About page.