Notion MCP server fails in Cursor with "Error in MCP: Client closed"

Question

I'm trying to set up the official Notion MCP server in Cursor 0.48.9 on macOS (arm64) following the README, but both the npx and Docker options fail immediately with Error in MCP: Client closed and Connection closed. Is there a working configuration?

Originally asked on GitHub: https://github.com/makenotion/notion-mcp-server/issues/20

AgentArmorHQ team · Accepted Answer

The GitHub issue is still open, but a contributor posted a working Docker configuration in the thread. The README-style setups — both `npx -y @notionhq/notion-mcp-server` and passing the JSON env value inline in the `docker run` command — fail in Cursor 0.48.9 on macOS with `Error in MCP: Client closed` / `Connection closed`.

The configuration that worked for the contributor uses the `mcp/notion` Docker image, passes the env variable name as a separate `-e` argument, and puts the actual JSON in Cursor's `env` block:

```json
"notionApi": {
  "command": "docker",
  "args": [
    "run",
    "--rm",
    "-i",
    "-e", "OPENAPI_MCP_HEADERS",
    "mcp/notion"
  ],
  "env": {
    "OPENAPI_MCP_HEADERS": "{\"Authorization\":\"Bearer your_token_here\",\"Notion-Version\":\"2022-06-28\"}"
  }
}
```

Key difference from the README: don't inline the JSON as part of the `-e` value inside `args`; let Cursor inject it via the `env` map instead. The thread does not include a fix for the `npx` route, so it's still unresolved if you prefer that.

General advice, not from the thread: the Notion Bearer token sits in your MCP configuration, so keep that file out of version control and use a token with the minimum scope you need.

AgentArmorHQ team · Answer

**What @jeffatgametime tried on GitHub** (Didn't work)

Reporter tried the README npx command `npx -y @notionhq/notion-mcp-server` in Cursor 0.48.9; Cursor logs show `Error in MCP: Client closed` and `Connection closed`.

Source: https://github.com/makenotion/notion-mcp-server/issues/20

AgentArmorHQ team · Answer

**What @jeffatgametime tried on GitHub** (Didn't work)

Reporter tried `docker run --rm -i -e OPENAPI_MCP_HEADERS={"Authorization": "Bearer <token>", ...}` with the inline JSON set as the env value; same `Client closed` error.

Source: https://github.com/makenotion/notion-mcp-server/issues/20

AgentArmorHQ team · Answer

**What @gorokhovdenis tried on GitHub** (Worked)

A contributor reported success using `mcp/notion` with a separate `-e OPENAPI_MCP_HEADERS` argument and the JSON placed in Cursor's `env` block instead of inline in the command.

Source: https://github.com/makenotion/notion-mcp-server/issues/20#issuecomment-2829956771

Notion MCP server fails in Cursor with "Error in MCP: Client closed"

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