Medium unveiled a new application called TK on Monday, designed to integrate artificial intelligence more deeply into the writing process. The core concept behind TK is to simplify the transformation of ideas into written text by embedding an AI assistant directly within the editor—users can summon help by typing "@TK" followed by their request or prompt. In the publishing and journalism world, "TK" traditionally functions as a placeholder indicating where missing information should be inserted later. The abbreviation stands for "to come," but employs a "K" rather than a "C" because very few English words contain the "tk" letter combination, making it easier to spot in written text where proofreaders would catch it. Within Medium's app, TK assumes a fresh purpose by helping users fill in those blanks. According to the company, the AI assistant could answer questions that would typically require switching to another browser tab—such as how many days are in a given month. The app can also retrieve fragments of writing previously saved to the platform while users were still developing their ideas. Additionally, Medium says TK will come equipped with specific capabilities for editorial feedback, headline feedback, and other functions that can align your draft with the style guide of Medium publications.

Medium's decision to embrace AI during the early stages of writing may prove contentious at a moment when the publishing and literary communities have been grappling with the role artificial intelligence plays in producing new long-form prose. Several authors have lost book deals amid suspicions they used AI technology to assist their writing, while other literary awards have faced scrutiny after winners were suspected of writing with AI assistance. Although writers have long relied on automated tools for proofreading and minor grammatical corrections, there is mounting concern throughout the publishing industry that an AI assistant's editorial "suggestions" could become the writing itself, rather than reflecting the thoughts in the writer's own mind. However, because AI models were trained on human writing, questions also persist about the reliability of AI detection tools—specifically their ability to properly determine when something was written with AI versus merely with its assistance, versus not at all. TK leans into this debate, taking the position that these nuances will ultimately cease to matter. Instead, the company champions what AI can contribute to the writing world, stating that "artificial intelligence makes writing more important, not less," and declaring that "AI is a technology that has the power to amplify human intelligence and it uses the written word as a foundation."

Nevertheless, Medium acknowledges that AI does raise the possibility of low-quality content and blurring the boundary between what's human-written versus AI-written. To address these concerns, TK enables authors to publish notes that transparently explain how AI was used in their writing. "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 explained in a blog post about the launch. Beyond writing assistance, TK will help users remember and organize what they had previously written and suggest writing prompts. The app can also optionally connect to your own AI agent through TK's MCP server or Claude skill, so the app can better understand your projects, your positions, and other ideas that could be stored in your agent's memory. Meanwhile, the new app incorporates human feedback in a social layer, according to the company, allowing writers to share their early drafts with others and receive feedback. At launch, TK is available on the web, but a desktop app is on the roadmap, Medium says. The app can import and export Markdown, but it's not a Markdown app itself. The writing in TK is also not encrypted, as the app is designed for collaboration, but users will be able to set access control permissions on their work. Medium, which is profitable, says TK will be a free tool for those with a Medium account.