The short version
Hjarni is a knowledge base your AI can actually use. Write notes in Markdown. Organize them in folders. Connect ChatGPT or Claude via a built-in MCP server. Your AI reads your notes and follows your instructions. What one conversation saves, the next can retrieve.
The problem it solves
Your AI often lacks the project notes, research, and decisions a task needs. So you explain your project. Your preferences. Your decisions. Then the conversation ends, and next time you explain them again.
Hjarni fixes that by giving your AI long-term memory through notes you control. When connected, ChatGPT and Claude can search your knowledge base, retrieve relevant context, and update notes as you work. No more pasting the same background into every chat.
How it works
1. Write notes
Plain Markdown. Folders, tags, wiki-links. Organize however your brain works.
2. Connect your AI
Connect Hjarni from the ChatGPT Apps Directory or the Claude Connectors Directory and sign in. Takes two minutes. No local server or code required.
3. Your AI reads and updates
Your notes stay put between chats, and a connected assistant can retrieve the ones a task needs. Ask it to check Hjarni before answering, to save useful decisions, and to update a note when a fact changes.
What makes it different
- AI-native, not AI-added. The MCP server isn't a plugin bolted on. The app was built around it. Your AI doesn't just search your notes. It understands your structure and follows your instructions.
- Simple on purpose. No databases. No kanban boards. No page builders. Notes, folders, and a connection to your AI. The constraint is the feature.
- You own the instructions. Set custom AI instructions per folder, per team. Your AI follows your conventions. Not its defaults.
- No bundled AI. You bring your own. No per-message costs. No token limits. No surprises on your bill.
Who uses Hjarni
Architecture docs, conventions, debugging playbooks. Your AI knows your stack.
Literature notes, hypotheses, synthesis docs. Your AI helps you think.
Strategy, meetings, decisions. Your AI knows your company.
Style guides, research, drafts. Your AI writes like you.
What does "Hjarni" mean?
Hjarni is an Old Norse word meaning brain or mind. It's what the product does: give your AI a brain it can use across conversations.
Most AI tools give you a chatbot. Hjarni gives your AI a brain.
Pricing
Free: up to 25 notes with full API and MCP access, 20 MB of file attachments across 5 files, and view-only public links. No trial. No expiration.
Pro: $12/month. Your AI's full memory: unlimited notes, unlimited file attachments, and public links guests can edit.
Teams: $20/seat/month. Shared knowledge base with member management.
Frequently asked questions
What is Hjarni?
A simple knowledge base that gives ChatGPT and Claude long-term memory. Write notes in Markdown. Connect your AI via a built-in MCP server.
How does Hjarni work?
You write notes. Your AI reads them. Hjarni has a built-in MCP server, so a connected ChatGPT or Claude can search, read, create, and update your notes when a task calls for it. Your notes stay available without you copying and pasting them into every chat.
Who is Hjarni for?
Anyone tired of re-explaining context to their AI. Developers, researchers, founders, writers, and teams.
Is Hjarni free?
Yes. 25 notes with full API and MCP access. No trial. No expiration.
What does Hjarni mean?
Old Norse for brain. It's what the product does: give your AI a brain it can use across conversations.