# WhyVault

> A hosted Markdown vault with a built-in MCP server. Claude, ChatGPT and Cursor read and write the same memory. EU-hosted, export anytime.

- MCP server (Streamable HTTP): https://mcp.whyvault.io – sign-in via OAuth 2.1 (Claude, ChatGPT) or a personal access token (Claude Code, Cursor).
- Create an account: https://app.whyvault.io/login?mode=signup – free, no credit card.
- Pricing: Free up to 20 own notes; Pro €9.99 / month or €99 / year (VAT included).
- Data: hosted in Frankfurt (EU), operated by Ohrlaf GmbH. Notes are plain Markdown and can be exported as a zip at any time.
- Agents can read, search, create and edit sections. Deleting is off by default; the user can allow it per connection, and deleted notes go to a trash where they can be restored. Every change appears in the history with the agent's name and can be undone.
- Contact: hello@whyvault.io

Every page is also available as Markdown: append `.md` or request it with `Accept: text/markdown`. All docs in one file: llms-full.txt.

## Docs

- [What is WhyVault?](https://whyvault.io/docs.md): WhyVault is a hosted Markdown vault with a built-in MCP server: one memory every AI agent can read and keep up to date. How it works, in 2 minutes.
- [Quick start](https://whyvault.io/docs/quickstart.md): From sign-up to your first agent writing into your vault in five minutes. No install, no config files, no API keys to copy.
- [The structure](https://whyvault.io/docs/structure.md): How a WhyVault is organised: rooms for each area of your life, knowledge, calendar and system notes – plus the five rules that keep it clear.
- [History, export and privacy](https://whyvault.io/docs/control.md): Every agent edit is versioned and reversible. Export your vault as plain Markdown anytime. Hosted in Frankfurt (EU), GDPR-compliant.
- [Overview](https://whyvault.io/docs/agents.md): How an AI agent connects to your vault: add the MCP address, sign in, approve. Guides for Claude, ChatGPT, Cursor, Claude Code and more.
- [Claude](https://whyvault.io/docs/agents/claude.md): Add WhyVault as a custom connector in Claude on web, desktop and mobile: paste the URL, sign in, switch it on in a chat. Step by step.
- [ChatGPT](https://whyvault.io/docs/agents/chatgpt.md): Turn on ChatGPT developer mode and connect an MCP server step by step – with the plans that support it and fixes for common errors.
- [Cursor](https://whyvault.io/docs/agents/cursor.md): Add WhyVault as a remote MCP server in Cursor so it remembers your decisions and context across projects. Setup in under two minutes.
- [Claude Code](https://whyvault.io/docs/agents/claude-code.md): Give Claude Code a persistent memory across projects with one command: claude mcp add, sign in, done. Plus how it fits with CLAUDE.md.
- [Other MCP clients](https://whyvault.io/docs/agents/other.md): Connect any client that supports remote MCP servers: endpoint, Streamable HTTP transport, OAuth 2.1 sign-in – everything a client needs.
- [Allow deleting](https://whyvault.io/docs/agents/delete.md): How a connected agent can move notes to the trash – per connection, off by default.
- [MCP tools](https://whyvault.io/docs/reference/mcp-tools.md): Every MCP tool a connected agent uses to search, read and update your vault – parameters, behaviour and examples.

## Guides

- [Obsidian MCP with Claude & ChatGPT – Even on Mobile](https://whyvault.io/guides/obsidian.md): Connect Obsidian to Claude, ChatGPT and Cursor via MCP: the local setup step by step, its limits, and a cloud vault that also works on your phone.
- [Company operating system: how I run my startup with AI](https://whyvault.io/guides/company-os.md): My company operating system: one room per venture, a decision log with reasons, a 15-minute weekly review – and Claude, Claude Code and ChatGPT read it all.
- [LLM Wiki (Karpathy): Your AI Second Brain, Ready to Use](https://whyvault.io/guides/llm-wiki.md): Karpathy’s LLM wiki explained: an AI keeps your knowledge as Markdown. With a template to copy, examples, and local vs hosted for Claude & ChatGPT.
- [Claude Memory: Built-in, Projects or a Shared Vault?](https://whyvault.io/guides/claude-memory.md): Claude memory explained honestly: what built-in memory and Projects do well, where they stop, and when an AI memory shared over MCP is worth it.
- [Claude Connectors: How to Add a Custom Connector](https://whyvault.io/guides/claude-connectors.md): Claude connectors explained: what they are, how to add a custom connector with a remote MCP URL, which ones are worth it and how to keep permissions tight.
- [Claude Code Memory: CLAUDE.md vs. MCP – What Goes Where](https://whyvault.io/guides/claude-code-memory.md): How Claude Code remembers: CLAUDE.md, auto memory and a shared memory over MCP. A rule of thumb for what goes where, setup and templates to copy.
- [ChatGPT Memory: Share It With Claude and Cursor](https://whyvault.io/guides/chatgpt-memory.md): ChatGPT memory explained honestly: saved memories, chat history and Projects, where they stop, and how to share one memory with Claude and Cursor over MCP.
- [MCP Memory Server: Local vs Hosted, What to Look For](https://whyvault.io/guides/mcp-memory-server.md): What a memory MCP server is, local vs hosted, and what to check: OAuth, versioning, export, EU hosting. Plus setup for Claude, ChatGPT and Cursor.
- [Decision Log Template: How to Document Decisions](https://whyvault.io/guides/decision-log.md): A free decision log template to copy: question, options, rationale, assumptions. When a decision deserves a record, and how Claude writes it for you.
- [What Is MCP? The Model Context Protocol, Explained](https://whyvault.io/guides/mcp.md): What is MCP? The Model Context Protocol in plain English: clients, servers, tools, local vs remote – and how to add an MCP server to Claude or Claude Code.
- [Claude GDPR: Using Claude and ChatGPT With Your Data](https://whyvault.io/guides/gdpr.md): Claude, ChatGPT and the GDPR: where your data goes when an AI agent reads your notes, what to check with the AI provider, and a checklist before you connect.
- [AI Second Brain: Build a Second Brain with AI Agents](https://whyvault.io/guides/ai-second-brain.md): What an AI second brain is, three ways to build one compared honestly, a structure and rules note to copy, and four workflows for every day.
- [Basic Memory vs WhyVault: Local or Hosted MCP Memory?](https://whyvault.io/guides/basic-memory-alternative.md): Looking for a Basic Memory alternative? A fair comparison: setup, clients, versioning, permissions, export, cost. When each fits and how to switch.

## Weekly digest

- [Week 40, 2026: Agents with a memory you can’t see](https://whyvault.io/blog/2026-w40-memory-you-cannot-see.md): OpenAI’s new agents remember more than you can see · OpenAI halts GPT-6.1 Astra – is it about liability? · Anthropic’s IPO prospectus has leaked · Study: many MCP servers are a blind spot · Bauckhage: “We haven’t seen anything yet”

## For agents

- [MCP Server Card](https://whyvault.io/.well-known/mcp/server-card.json): endpoint, transport, auth and tools
- [Agent Skill](https://whyvault.io/.well-known/agent-skills/whyvault/SKILL.md): how an agent connects to and uses WhyVault
- [llms-full.txt](https://whyvault.io/llms-full.txt): all docs as Markdown

## Optional

- [Homepage](https://whyvault.io/): product, pricing
- [Terms](https://whyvault.io/terms)
- [Privacy](https://whyvault.io/privacy)
- [Legal notice](https://whyvault.io/imprint)
- [Data processing agreement](https://whyvault.io/dpa)
- [Deutsche Fassung](https://whyvault.io/de/llms.txt)