# An MCP knowledge base your AI can read and write. Hjarni is a Markdown knowledge base with an official MCP server. Compatible Claude and ChatGPT clients can search, read, create, and update your notes. Ask your assistant to retrieve the relevant notes and check its changes. ## Stop pasting. Start connecting. A new chat may lack the decisions, research, and working agreements you need. Keep that context in maintained notes, then ask your connected assistant to retrieve the relevant material. An MCP server gives a compatible assistant tools to search and read that library. The assistant still has to call those tools; inspect what it retrieved before relying on the answer. Hjarni is that knowledge base. Its official MCP server is hosted by Hjarni. ## Save notes once. Connect with MCP. Save your notes and connect a compatible assistant. In each conversation, ask it to retrieve the relevant context before answering. 1. **Write it down** Notes in plain Markdown, organized in folders and tags. The format your AI already speaks. 2. **Connect the MCP server** Add Hjarni once in Claude or ChatGPT. Sign in. That is the whole setup. 3. **Your AI reads and writes** Claude and ChatGPT search your notes, follow your instructions, and save new notes back to the right folder. One MCP server URL ``` https://hjarni.com/mcp ``` Step-by-step for [Claude](https://hjarni.com/docs/connect-claude-mcp), [ChatGPT](https://hjarni.com/docs/connect-chatgpt-mcp), and [every other client](https://hjarni.com/for). Check a config with the [MCP config validator](https://hjarni.com/mcp-config-validator). ## A toolset your AI won't get lost in. Light and well defined. Search, read, create, update. Just enough for your AI to use it well, with no sprawling surface area to wander into. ### Read and write Search, read, create, and update notes. Your AI is not a read-only guest. It keeps your knowledge base current. ### Markdown end to end Notes go in and come out as Markdown. No conversion, no lossy formats, no lock-in. Export everything anytime. ### It carries your rules The server hands your [per-folder instructions](https://hjarni.com/folder-instructions) to whichever AI is reading, so it writes notes that fit your system. > I wanted a cloud knowledge base I could use as memory for my AI, in plain Markdown, with read and write access. Nothing else fit. Hjarni did. What sold me was how light and well defined the MCP is. My AI used to choke when I pasted Markdown and config files into a chat. It reads them perfectly from Hjarni. The folder-level AI instructions and the knowledge graph are the parts I did not know I needed. Jack, GTM Strategy Consultant ## Claude and ChatGPT. One knowledge base. Connect the same MCP server to every AI tool you use. No copy-paste between them. No vendor lock-in. See it with one launch plan: ChatGPT saves it, Claude changes the opening date, and a new ChatGPT chat retrieves the update. [See ChatGPT and Claude use the same note](https://hjarni.com/knowledge-base-for-chatgpt-and-claude#shared-notes-demo). Claude Connect via MCP. Two minutes. [Set up Claude](https://hjarni.com/docs/connect-claude-mcp) ChatGPT Connect via MCP. Two minutes. [Set up ChatGPT](https://hjarni.com/docs/connect-chatgpt-mcp) Also Cursor, Claude Code, Windsurf, Cline, Copilot, and more. See [every integration](https://hjarni.com/for). ## Not another chatbot bolted onto notes. ChatGPT memory Native personalization inside ChatGPT, with memory controls in Settings. Hjarni adds explicit Markdown documents for different connected assistants. Compare [Hjarni vs ChatGPT memory](https://hjarni.com/compare/hjarni-vs-chatgpt-memory). Claude Projects Persistent project knowledge, instructions, and chats, with sharing on eligible plans. External tools and editing depend on the account, project version, and permissions. Compare [Hjarni vs Claude Projects](https://hjarni.com/compare/hjarni-vs-claude-projects). A bare MCP wrapper over a database A protocol endpoint is not a knowledge base. You still need somewhere to write, organize, and read your notes as a human. Hjarni is both. Hjarni A real knowledge base you read and write as Markdown, plus an official MCP server and full REST API. Same notes in Claude, ChatGPT, and every MCP client. Common questions ## Questions about an MCP knowledge base **What is an MCP knowledge base?** A knowledge base with an MCP endpoint that gives a compatible assistant tools to retrieve content and, where permitted, create or update it. Hjarni provides Markdown notes, folders and tags through an official hosted MCP server. The assistant still needs to call the relevant tools. **What MCP server should I use for a knowledge base?** Choose by the content model, connection, permissions and tools you need. Hjarni provides official hosted MCP for shared Markdown notes. Other products offer hosted or local connections and different editing workflows. Check your actual client and account before choosing. **Can ChatGPT and Claude write to my notes, or only read?** Compatible connected clients can search and read notes, create or update them, add tags and file them in folders through permitted tools. Folder instructions guide how an assistant works; permissions enforce access. Normal OAuth connections retain the account’s access, while scoped manual agent tokens can narrow a compatible connection. Review saved edits in note history. **How is this different from ChatGPT memory or Claude Projects?** ChatGPT Memory provides native personalization with controls that vary by account and surface. Claude Projects provides persistent project knowledge, instructions and chats, with sharing on eligible plans. Hjarni adds a separate maintained Markdown library that different compatible assistants can retrieve and update. **Do I need a paid plan to connect an MCP server?** Hjarni Free includes 25 personal notes and full MCP access without a first-party token meter. Assistant connection availability, write tools and approvals depend on the client, account and workspace. Your assistant’s subscription and usage limits are separate. ## Your notes on every device **Hjarni has its own native apps.** Free on every plan for [iPhone, iPad and Apple Silicon Mac](https://apps.apple.com/app/id6761733903) and [Android](https://play.google.com/store/apps/details?id=com.hjarni.app). Same account, same notes as the web. An internet connection is required.