Medium Launches TK, a Free AI Notebook App That Discloses Exactly How Much AI Touches Your Writing

Medium, the publishing platform that spent years watching AI-generated content flood its feeds, has decided the answer is to lean in, loudly and on the record. On Monday it launched TK, an AI-powered notebook, journaling and private social networking app, and its first major product launch since 2017. TK is free for anyone with a Medium account, available on the web at launch with a desktop app on the roadmap.

The AI assistance is built into the writing flow rather than bolted on. TK ships with skills for editorial feedback and headline feedback, and can match a draft against the style guides of Medium publications. It also helps writers remember and organize what they have written before, and suggests writing prompts when the page is blank.

The most distinctive part is the provenance stance. "Artificial intelligence makes writing more important, not less," the company declares, calling AI "a technology that has the power to amplify human intelligence and it uses the written word as a foundation." At the same time Medium concedes that AI blurs the line between human and machine writing. TK's answer is disclosure: authors can publish notes that transparently explain how AI was used. "This is a start of what we believe is required to publish in the AI era, which is to make the provenance of writing clear, transparent, and inspectable, right down to the prompting and source material," Medium said in its launch blog post.

TK is also designed to plug into the agent stack writers increasingly live inside. The app can optionally connect to your own AI agent through TK's MCP server or a Claude skill, so the agent can understand your projects, positions and stored ideas. That positions TK not just as a writing tool but as a memory layer that other AI systems can read.

A social layer rounds it out. Writers can share early drafts with others, gather human feedback, and set access-control permissions on their work. The app imports and exports Markdown, though it is not itself a Markdown app, and writing in TK is not encrypted, a deliberate trade-off for a tool designed for collaboration.

The launch lands in an industry at war with itself over AI. Publishers are watching traffic drain into chatbots and AI summaries, Google's own ad revenue growth has slowed as AI search expands, and platforms face a steady tide of low-effort generated content. Medium, which says it is profitable, is betting that transparency, rather than prohibition, is the sustainable middle ground.

That bet will be tested in public. If TK's disclosure model catches on, AI-assisted writing stops being something platforms quietly tolerate and becomes something readers can inspect, which would be a genuine shift in how the publishing economy prices human effort.