Cursor: add a shared memory with a remote MCP server

Updated 30 October 2026. Steps taken from Cursor's official documentation, read on 30 October 2026. Cursor's interface moves fast: if a label has changed, the mcp.json format stays the same.

To give Cursor a persistent memory, add a remote MCP server to ~/.cursor/mcp.json (all your projects) or .cursor/mcp.json (one project), under the mcpServers key, with its url. Cursor handles the OAuth sign-in to the server, then the agent uses its tools when they are relevant. This guide uses Pryzm Memory as the example: a memory shared across several AIs over MCP (Model Context Protocol).

Why bother: Cursor's agent is excellent inside a project, but it starts from scratch in every new chat. With an MCP memory, it finds your technical decisions, solved bugs and preferences, including what you told Claude or ChatGPT.

What you need

• Cursor, a recent version.
• A Pryzm account. Free up to 100 memories; on the free plan, your email must be confirmed before you connect an AI. Keep your Pryzm username handy: the sign-in page asks for it, not your email.

The steps

1. Open the MCP configuration file. Edit ~/.cursor/mcp.json directly, or go through Cursor's Customize page, where MCP servers are installed and managed.
2. Paste the configuration below. If the file already lists other servers, add only the pryzm-memory block inside mcpServers. Save.
3. Sign in. In Customize, Pryzm shows up among the MCP servers with a sign-in prompt. Follow it: your browser opens the Pryzm page, enter your username and password. Cursor then renews the token by itself.
4. Check. Pryzm's tools (memory_search, memory_store…) appear in the list of available tools. A toggle in Customize turns the server off without removing it.
5. Add a rule. Paste the “main memory” instructions into Customize → Rules as a user rule: it applies to all your projects and is used by the agent.
6. Test in the agent chat: “Check Pryzm for what we decided about authentication.” By default, Cursor asks for your approval before using an MCP tool.

{
  "mcpServers": {
    "pryzm-memory": {
      "url": "https://pryzm-memory.com/mcp"
    }
  }
}

The ready-to-paste instructions are on the connection page. The file format and options are described in Cursor's MCP documentation.

For a single project

The same JSON block in .cursor/mcp.json, at the repository root, applies to that project only. For a project-specific rule, use a file in .cursor/rules, committed with the code. Each developer signs in with their own account: memory is not shared between accounts.

If something doesn't work

• The server stays in error: check the JSON is valid (commas, braces) and the URL is exact, with no space or trailing slash.
• No sign-in prompt: save mcp.json, then restart Cursor.
• “Incorrect username or password”: use your Pryzm username, not your email.
• The agent never calls Pryzm: check the server is enabled in Customize and the rule is added, then mention “Pryzm” in your request.
• Copied from VS Code: the format differs. Cursor expects mcpServers; VS Code's .vscode/mcp.json uses servers.

What the server sees

The server receives what the agent sends it: a search, or the text of a memory to save. Not your code, unless the agent puts it in a memory. At Pryzm, each account is encrypted with its own key (AES-256-GCM), with servers in Germany; during a session, the server decrypts your memories in memory so it can search them, so it is not end-to-end encryption. API keys and passwords are refused when saving.

When it isn't useful

If you only code with Cursor, on a single project, its rules and the repository context are probably enough. An external memory helps when you switch tools: Cursor to code, Claude Code in the terminal, Claude or ChatGPT to think. For VS Code, see the VS Code and Copilot guide.