Cursor
Add WhyVault to Cursor as a remote MCP server – so Cursor remembers your decisions and context across every project.
Requirements
- Cursor: a current version with support for remote MCP servers and OAuth sign-in. Update via Cursor → Check for Updates if the steps below look different.
- Cursor plan: any. MCP servers aren't tied to a specific plan.
- WhyVault: any account, Free included.
- Choose how to sign in: OAuth in the browser (no key in the file) or an access key in the header.
Set it up
Add the entry
Add WhyVault to your MCP configuration – globally in ~/.cursor/mcp.json or just for one project in .cursor/mcp.json:
{
"mcpServers": {
"whyvault": {
"url": "https://mcp.whyvault.io"
}
}
}If the file already has other servers, add whyvault as one more entry inside mcpServers.
Sign in
On first access, Cursor opens the WhyVault sign-in window. After that WhyVault shows up under Customize in the sidebar in the list of MCP servers and can be used in the agent chat.
After approving, your browser asks to open Cursor again – allow it, that's how the sign-in gets back to Cursor.
Try it
In the agent chat, ask:
Read my WhyVault and summarise the decisions for this project.Cursor shows which tool it wants to run and asks for confirmation, unless you allowed it to run tools automatically.
With an access key instead of signing in
Prefer no sign-in window? Create an access key in the app under Connect agents – the app then shows you exactly this entry to copy:
{
"mcpServers": {
"whyvault": {
"url": "https://mcp.whyvault.io",
"headers": { "Authorization": "Bearer wv_…" }
}
}
}Keep keys out of .cursor/mcp.json in a repository – everything in it lands in Git. For projects, use OAuth or the global file.
Make Cursor use the memory
Cursor doesn't know when WhyVault is worth asking. A short rule helps – in Rules in Cursor's settings or as a file in .cursor/rules/:
Use the WhyVault MCP server as long-term memory. Before larger changes, search it for earlier
decisions on the topic. Record decisions with consequences in the project's room.Troubleshooting
WhyVault doesn't appear in the list
- Check the JSON: a missing comma or a trailing comma breaks the whole file.
- The key must be
mcpServers. VS Code usesservers– that doesn't work in Cursor. - The project file only applies if it's in
.cursor/mcp.jsonat the root of the opened folder. - If Cursor doesn't pick up the change, reload the window (Developer: Reload Window) or restart Cursor.
The sign-in window doesn't open
Open the MCP list and click the sign-in button next to WhyVault. If the browser opens but doesn't return to Cursor, allow it to open Cursor. If your mail app opens the sign-in link in a different browser, type the code from the email in the sign-in window instead.
The server shows an error or a red dot
Open View → Output and choose MCP Logs in the drop-down. A 401 means the access key is wrong or revoked, or the sign-in expired – create a new key or sign in again. Check that the address is exactly https://mcp.whyvault.io.
The agent doesn't use WhyVault
Make sure WhyVault is switched on in the MCP list and you're in the agent chat. If you have many MCP servers, Cursor may hand only some of their tools to the model – switch off the ones you don't need.
Write tools are missing
The connection is set to read only. Change it under Connect agents → Permissions in WhyVault, then switch the server off and on in Cursor so it reloads the tool list.
"Too many changes in a short time"
WhyVault slows down a connection that writes an unusual amount per minute. Ask the agent to bundle its changes.
FAQ
Global or per project?
Global (~/.cursor/mcp.json) is the usual case: one memory for all projects, each with its own room in the vault. Per project makes sense if only one repository should see it.
Does the vault replace Cursor rules?
No. Rules say how to work in a repository. WhyVault holds why things were decided – across projects and across tools like Claude or ChatGPT.
Can Cursor delete notes?
Only if you allow it for this connection. It then moves notes to the trash, where you can restore them.
Where is my data?
WhyVault is EU-hosted (Frankfurt) and GDPR-compliant. Whatever Cursor reads goes to the model provider you use in Cursor. Details: History, export and privacy.