Medium’s TK puts a free AI assistant inside the writing editor

By Grace Kim

Medium launched TK on Monday and says the web-based AI writing assistant will be free to people with a Medium account, with a desktop app on the roadmap.

How does TK work inside a draft?

Medium said writers can call the assistant by typing “@TK” and then entering a request or prompt. The command sits inside the editor, allowing the tool to help shape an idea into written words without leaving the draft.

TK borrows a convention from journalism: writers use “to come” to mark information they plan to add later. Medium uses the letter K instead of C because few English words contain “tk,” which makes the placeholder easier for proofreaders to spot. TK turns that marker into a prompt for the assistant to fill the gap.

The assistant can help answer quick factual questions, such as how many days are in a particular month, that would normally send a writer to another browser tab. It can also pull in writing the user saved earlier in TK while developing an idea, according to Medium.

Medium also said TK will ship with skills for editorial feedback and headline feedback. TK could also match a draft against the style guide for Medium publications.

The practical result is one in-draft command for quick facts, earlier material and feedback.

Why is AI assistance inside an editor controversial?

Medium acknowledged that TK arrives amid growing scrutiny of AI in long-form publishing. It said multiple authors had lost book deals over suspicions that they used AI to help write, while literary awards had come under scrutiny after winners were suspected of writing with AI assistance.

Medium noted that writers have long used automated tools for proofreading and light grammatical edits. Its concern is that editorial suggestions can become the writing itself, rather than simply reflect what the writer had in mind.

Medium also pointed to the limits of AI-detection tools. Because models train on human writing, detectors may struggle to distinguish text written entirely by AI from text produced with AI assistance or written without it.

Medium wrote that “artificial intelligence makes writing more important, not less,” and proclaimed that “AI is a technology that has the power to amplify human intelligence and it uses the written word as a foundation.”

That position makes Medium’s bet explicit: the company expects those distinctions to matter less as AI assistance becomes embedded in the writing process.

What does Medium mean by transparent AI use?

Medium conceded two risks: AI can produce low-quality content, and it can blur the line between human-written and AI-written work. Its response is a disclosure layer. Writers can publish notes that explain how AI was used in their writing.

Medium explained in its launch blog: “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.”

The notes make AI’s role visible instead of leaving readers to infer it.

Can TK connect writers to agents and other people?

Medium said TK will also remember and organize writing the user created earlier and suggest prompts for new work. The app can optionally connect to a user’s own AI agent through TK’s MCP server or Claude skill. That connection can help TK understand the user’s projects, stated positions and other ideas stored in the agent’s memory.

Medium added a social layer for human feedback. Writers can share early drafts with other people and receive their feedback through the collaborative workflow.

Those features position TK as both a project memory and a shared feedback layer.

What is available at launch?

Medium said TK is available on the web at launch and that a desktop app is on the roadmap. It can import and export Markdown, though Medium stressed that TK is not itself a Markdown app.

Writing inside TK is not encrypted because the product is designed for collaboration. Medium said users will be able to set access-control permissions on their work, providing a partial answer to that limitation.

Medium, described in the launch coverage as profitable, says TK will be free for people with a Medium account. The launch trade-offs are explicit: no encryption, but user-controlled access, plus Markdown exchange without a Markdown-only environment.

The launch favors access and collaboration over local-only privacy and a fixed document format.

Medium’s next test is whether desktop access, agent connections and transparent AI notes can expand daily use without intensifying the authorship and detection debate already attached to AI-assisted writing.