Your AI starts from zero every conversation. Hjarni fixes that.

Write a note on your phone. Ask Claude or ChatGPT about it on your laptop, and it already knows.

Hjarni is a Markdown knowledge base with a built-in MCP server. Notes, folders, tags. That is the whole product. MCP is not a plugin bolted on afterwards. The app was built around it.

Call it a second brain, a personal wiki, a PKM system or a Zettelkasten. It is one place to keep what you know, in plain Markdown, so both you and your assistant can read it.

HOW IT WORKS

Save a note once. Connect Claude, ChatGPT, or any MCP client. Your AI reads your notes, follows your instructions, and writes new notes that fit your system.

Stop re-explaining your stack, your customers, or your style guide at the start of every conversation. Write once. You both remember.

ON YOUR PHONE

Capture a note in seconds from the New tab. Triage it later from the Inbox. Search everything you have written. Read anywhere.

This is the capture and read-anywhere companion. The long editing sessions happen on the web. That is on purpose.

ONE BRAIN, EVERY ASSISTANT

Claude and ChatGPT each keep their own memory, and neither one shares. Hjarni sits outside both. Switch assistants, keep your context. Works with Claude, ChatGPT, Claude Code, Cursor, and anything else that speaks MCP.

MEMORY YOU CAN ACTUALLY READ

Assistant memory is a black box. Hjarni is not. Every note is plain Markdown you can open, search, and edit. Every change is versioned, so you can see what your AI wrote, diff it, and revert it. Export everything, any time, in a format that opens anywhere.

SHARE A BRAIN WITH YOUR TEAM

Team folders give everyone the same context. Your conventions, your decisions, your onboarding docs. Every teammate's AI reads the same thing, so nobody has to be the person who remembers.

YOU OWN THE INSTRUCTIONS

Set instructions per folder and per team. Tell your AI how to format notes, which tags to use, what tone to write in. Your AI works the way you work.

SIMPLE ON PURPOSE

We left features out on purpose. No databases. No kanban boards. No page builders. Hjarni is a place to write and organize. The constraint is the feature.

WHO IT IS FOR

Developers, teams, founders, researchers, writers, travelers. Anyone who has typed the same context into a chat window twice.