The best MCP knowledge base

A clear, honest comparison of the leading MCP knowledge bases and MCP note apps for giving ChatGPT and Claude a memory.

Comparison refreshed 20 October 2026

Short answer

There is no single best MCP knowledge base; the right one depends on what you need. Hjarni suits shared, hosted Markdown notes that compatible ChatGPT and Claude clients can read and update. For application or coding-agent memory, consider Mem0 or MemCP; for visual research, Heptabase; for spaced-repetition study, RemNote.

Start with 25 free notes

No credit card required. AI subscriptions are separate.

How to compare them

We publish Hjarni. This comparison is based on the linked vendor docs and maintainer repositories, checked 19–20 October 2026. It is not a hands-on benchmark.

Compare five things: who maintains the MCP server, read and write access, exportable Markdown, ChatGPT and Claude compatibility, and local or hosted access. Pick the tradeoff that fits your work.

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Comparison of MCP knowledge bases on use case, MCP hosting, web assistant access, editing, Markdown export, and tradeoffs.
Tool	Best for	MCP and hosting	ChatGPT / Claude web	Editing and Markdown	Main tradeoff
Hjarni	Shared, editable Markdown notes for ChatGPT and Claude Free apps for iPhone, iPad, Apple Silicon Mac and Android	Official, hosted (OAuth) Hosted (EU) Source for Hjarni	Direct hosted connection	Read, create and update notes Markdown notes; ZIP export Storage and export details	Focused knowledge base; no offline mode.
Notion	Databases, documents, and project management together	Official hosted MCP Hosted Source for Notion	Direct hosted connection	Read, create and update pages Pages export as Markdown; databases as CSV Storage and export details	Choose it if you also need a workspace; export does not preserve every Notion feature.
Obsidian	A Markdown vault on your own disk	Community HTTP server Local files; self-hosted server Source for Obsidian	Linked server supports remote OAuth	Read, create and edit notes Native Markdown files Storage and export details	The linked community server is one option. Local agents can also use vault files or Obsidian’s official CLI.
Joplin	Open-source notes with optional encrypted sync	Official, local Local MCP; optional sync Source for Joplin	Requires a separate bridge	Read, create and update; enable tools individually Markdown export; JEX for a lossless backup Storage and export details	Desktop MCP listens on localhost; syncing notes does not make MCP remotely accessible.
Logseq	Block-based outlines and journals	Official, local MCP in DB desktop/CLI Local HTTP endpoint Source for Logseq	Separate reachable bridge needed for a cloud client	Supported DB tools vary; check the current tool list DB SQLite storage; Markdown export has omissions; separate OG file graphs Storage and export details	DB is beta and collaboration is alpha. Do not apply OG file-storage claims to the DB product.
Heptabase	Visual research using cards and whiteboards	Official hosted MCP Cloud-connected apps Source for Heptabase	Hosted OAuth; ChatGPT setup documented	Read, create and edit cards Markdown export; visual layout may not transfer Storage and export details	Compatible remote clients include Claude; the product centres on visual research.
RemNote	Study notes and spaced repetition	Official, local desktop MCP Local MCP; synced or local notes Source for RemNote	No direct connection; local clients supported	Read, create, edit and tag notes Markdown export; native export keeps more detail Storage and export details	The desktop app must stay open for MCP access.
Basic Memory	Markdown memory with a local or cloud choice	Official local and Cloud MCP Local or subscription Cloud Source for Basic Memory	Cloud connects directly; local mode needs a local client	Read, create and edit notes Native Markdown; Cloud ZIP export Storage and export details	Cloud adds remote access and a web editor; local mode uses files on your machine.
Mem0 / OpenMemory	Memory for applications and coding agents	Official hosted MCP; open-source options differ Hosted and separate self-hosted options Source for Mem0 / OpenMemory	Hosted OAuth endpoint; check client support	Read, add, update and delete memories Memory records accessible through the API Storage and export details	Current OpenMemory setup links to Mem0's hosted MCP. Records can be edited; raw storage is also supported.
MemCP	Persistent context for Claude Code	Self-hosted MCP server Local / self-hosted Source for MemCP	Local Claude Code setup documented; remote setup unverified	Save, retrieve, delete and consolidate insights SQLite insights and context files; no Markdown export documented	Can load files, including Markdown, as context; general note editing is not documented.

How the category breaks down

Start with the knowledge you want to maintain. Notion combines documents with databases and project management. Obsidian keeps Markdown files in a vault. Heptabase centres on visual research; RemNote on study. Hjarni focuses on hosted Markdown notes that people and connected assistants can both read and update. Basic Memory offers Markdown with local and Cloud options. Mem0 and MemCP provide memory workflows for applications and coding agents. These categories overlap: Mem0 supports editing memory records and storing content without extraction.

Then check the connection you will use. Hosted MCP services can connect to compatible web assistants. The linked Obsidian server also supports remote OAuth, but you deploy and maintain it. Joplin and RemNote expose local desktop servers, so a web assistant needs a separate bridge. Logseq DB now includes official local HTTP MCP in its desktop and CLI; a cloud assistant still needs a separately reachable bridge. The DB product and separate OG file graphs differ in storage and export. For every tool, check client plans, permissions and which write operations are available.

Pick by what you actually need

Choose Hjarni

You want one durable, hosted knowledge base that ChatGPT, Claude, and other MCP clients read and write, in plain Markdown you own.

Choose Notion

You also want databases, project management, and a company wiki your external AI assistant can read and write.

Choose Obsidian

Local files and a plugin ecosystem matter most, and you will set up AI access yourself.

Choose Heptabase or RemNote

You want visual whiteboard thinking, or spaced-repetition study, with AI as a bonus.

Choose Mem0 or MemCP

You want to manage memory for an application or coding agent. Compare their record storage, editing tools and deployment requirements.

Choose Basic Memory

You want Markdown files on your own disk, with a hosted option if you later need remote access.

The best MCP knowledge base is the one every AI you use can read.

Try Hjarni with one decision

Connect ChatGPT or Claude to Hjarni.
Ask your assistant to save one useful project decision in Hjarni.
In a new chat, ask it to check Hjarni for that decision. Open the note and its history to inspect the saved content and any edits.

Your assistant needs to retrieve a note to use it. How to make checking your notes a habit.

Start with 25 free notes

25 personal notes free. No credit card required. AI subscriptions are separate.

Common questions

Questions about choosing an MCP knowledge base

What is the best MCP knowledge base?

It depends on your workflow. Hjarni suits people who want a hosted Markdown knowledge base they and compatible ChatGPT or Claude clients can read and update together. Notion suits a broader workspace, Basic Memory offers local and hosted Markdown options, and Mem0 suits application and coding-agent memory. Heptabase focuses on visual research; RemNote focuses on study. A connection makes knowledge available, but the assistant still needs to retrieve it.

What is an MCP knowledge base?

A knowledge base an AI assistant connects to over the Model Context Protocol. The assistant can retrieve stored content and, where supported, create or update it without you pasting it into the chat. Products may store Markdown notes, documents, or memory records. Compatibility depends on the client, connection method, and permissions; MCP support alone does not guarantee every client or operation will work.

Which MCP knowledge bases work with both ChatGPT and Claude?

Documented hosted options include Hjarni, Notion, Heptabase, Capacities, Mem and current Tana, with different plans and tools. Local products may need a local client or a separately configured bridge. Check the exact product edition, authentication, permitted actions and assistant availability.

Is Mem0 a knowledge base?

Mem0 provides memory infrastructure for applications and agents, with managed and open-source options. Its documented operations support updating stored memories and storing raw content without extraction. Hjarni focuses on Markdown notes organised in folders, with an official MCP server so people and connected assistants can both read and update them. Choose based on the workflow you want to maintain.

What is the best free MCP knowledge base?

Hjarni includes 25 personal notes and full MCP access on Free. Hjarni does not charge per AI message or token; your AI client's subscription and usage limits are separate. Open-source options such as MemCP can be self-hosted without a software subscription, but hosting and model-provider costs may still apply.

What is the best MCP knowledge base for a small business?

Choose one that fits how your team maintains its knowledge. Hjarni Teams suits shared positioning, customer context, and decisions kept as editable Markdown notes. Members can connect their own compatible ChatGPT or Claude client to read and update the same notes, with folder roles controlling edits. If you also need databases and project management, consider a broader workspace such as Notion; if you are building memory into your own software, consider an application memory service.

Apps and connections

On every device. In every assistant.

Native apps for iPhone, iPad, Mac and Android, and official listings in both the ChatGPT and Claude directories. One account, one set of notes.

Write and read anywhere

Web, any browser iPhone and iPad Mac Android Chrome web clipper

The apps are free, with the same features as the web. An internet connection is required.

Connect the assistant you already use

ChatGPT app Claude connector Cursor Claude Code 20+ MCP clients

Hjarni is listed in the ChatGPT Apps Directory and the Claude Connectors Directory, so connecting is an install, not a config file.

How to get Hjarni on each one

Start here

Write once. You both remember.

25 notes free, forever. No credit card required.

Start with 25 free notes

5 out of 5 from 14 reviews 13,400+ notes a day read or updated by AI

Works with Claude, ChatGPT, Cursor and any MCP client.