Medium launches TK, a notes app with AI in the editor

The name TK comes from the journalistic practice of using "TK" as a marker for missing information that will be added later. In the app, the symbol takes on a new role: helping to "fill in the gaps".

In this article you will see:

• What TK is and how the AI assistant works
• Organization and collaboration features
• How TK handles transparency in AI use
• Connection with external agents via MCP and Claude skill
• How to test TK today

What TK is

TK is a free app for Medium account holders, available on the web, with versions for Android and iOS and a desktop app on the roadmap. The core idea is to combine notes and journaling with something similar to a private social network, where you can share drafts with others and receive feedback.

The AI assistant is invoked directly in the editor: the user types "@TK" and formulates the request. The assistant can generate text, give editorial feedback, suggest titles and bring up excerpts from previously saved notes.

Medium describes TK as "Google Docs meets chat groups, meets blogging".

Main features

Beyond the assistant, TK brings some features worth highlighting:

• Specific skills for editorial feedback, title feedback and adherence to Medium publications style guide
• Organization of notes and drafts in "Libraries", private blogging spaces for collaboration without public view metrics
• Import and export in Markdown
• Optional connection with external agents via TK's MCP server or Claude skill, so the app better understands the user's projects and positions

Medium states that TK is not a Markdown app per se, but supports import and export in the format.

Transparency in AI use

One point Medium emphasizes is transparency. TK allows authors to publish notes explaining exactly how AI was used in writing. The company describes this as "the beginning of what we believe is necessary to publish in the AI era: making the provenance of writing clear, transparent and inspectable, down to the level of prompts and source material".

Medium acknowledges that AI raises the possibility of low quality content and blurring the line between what is written by humans and what is written by AI. The AI usage notes feature is the company's response to this concern.

The company also states that "artificial intelligence makes writing more important, not less", and that "AI is a technology that has the power to amplify human intelligence and uses written word as foundation".

For regular writers, TK can serve as a notepad that evolves into a publishing space. The ability to share drafts in private "Libraries", without public view metrics, creates a more relaxed collaboration environment, where it is possible to iterate on ideas before publishing them on Medium. Integration with external agents via MCP expands this possibility, allowing the app to access context from projects and positions stored in the agent's memory.

Connection with external agents via MCP

A neat technical detail for anyone working with AI agents: TK can connect to your own agent via TK's MCP server or a Claude skill. This lets the app better understand the projects, positions and other ideas stored in the agent's memory.

This integration puts TK in the ecosystem of tools that use the MCP protocol, the same standard used by other AI editors and CLIs, such as Vercel: Chat SDK transmits generative UI with json-render and Cursor: voice chat with agents in the editor.