Could not attach to MCP server filesystem

Describe the bug
I'm trying to implement various MCP servers, including the filesystem server, the memory server, and the playwright server. However, I keep getting failures.

I've uploaded a screenshot of the errors I get in the app. In the dev tools console, I see:

Could not attach to MCP server filesystem: eE: MCP error -2: Request timed out
  at https://claude.ai/_next/static/chunks/foo.js:1:4404
  at r (https://claude.ai/_next/static/chunks/bar.js:15:2950)
(anonymous) @baz.js:18

This is my config.json content:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "@modelcontextprotocol/server-filesystem",
        "/Users/myusername/code/"
      ]
    },
    "mcp-obsidian": {
      "command": "uvx",
      "args": ["mcp-obsidian"],
      "env": {
        "OBSIDIAN_API_KEY": "reallylongkey"
      }
    },
    "@modelcontextprotocol-server-memory": {
      "runtime": "node",
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    },
    "playwright": {
      "command": "npx",
      "args": ["-y", "@automatalabs/mcp-server-playwright"]
    }
  }
}

Note: MCP Obsidian DOES work--the other three do not.

To Reproduce
Steps to reproduce the behavior:

Set up config.json
launch Claude desktop app
Wait for error message to appear

Expected behavior
I expect to see something like this:

MCP Obsidian Server running on stdio
Allowed directories: [ '/users/myusername/code/pathtovault/vaultname' ]

Logs
This is what appears in the file /Users/myusername/Library/Logs/Claude/mcp.log:

2024-12-08T08:23:21.820Z [info] Attempting to connect to MCP server filesystem...
2024-12-08T08:23:21.823Z [info] Attempting to connect to MCP server mcp-obsidian...
2024-12-08T08:23:21.823Z [info] Attempting to connect to MCP server @modelcontextprotocol-server-memory...
2024-12-08T08:23:21.824Z [info] Attempting to connect to MCP server playwright...
2024-12-08T08:23:21.843Z [info] Connected to MCP server mcp-obsidian!
2024-12-08T08:23:21.845Z [info] Connected to MCP server filesystem!
2024-12-08T08:23:21.852Z [info] Connected to MCP server @modelcontextprotocol-server-memory!
2024-12-08T08:23:21.853Z [info] Connected to MCP server playwright!

Additional context
Like I said, it's working for obsidian, not for the other 3. Also, I AM able to connect to the filesystem server using MCP Inspector:

I had the file system working along with Brave search, now nothing is working.

It is very random. I also had file system + Brave search working in one instance. Then, after a restart of the Claude desktop without any changes in the configuration file, it stopped working. Now, rarely does the server filesystem work.

Looking into mcp-server-filesystem.log
When it works (rarely) this is what it looks like:
Secure MCP Filesystem Server running on stdio
Allowed directories: [ '/users/someone/documents/somedir' ]

When it doesn't work (most of the time) this is what it looks like:
command not found: /Users/someone/Documents/somedir

Same config file. No changes.

Its happening to me as well, even with just the fileserver installed.

I fixed my problem. I had a file listed in with the directories. That makes accessing the filesystem fail. I removed it, restarted the claude app, and file access reactivated through MCP.

@MikeyBeez

What kind of file @MikeyBeez? - and did it fail if you just ran

npx -y @modelcontextprotocol/server-filesystem /users/whaever/documents in a console?

I had included the claude desktop config json file in the list of allowed directories. I didn't get an error message except failure to connect via MCP.

(base) ➜  ~ npx -y @modelcontextprotocol/server-filesystem /Users/yuyang/Desktop 
Secure MCP Filesystem Server running on stdio
Allowed directories: [ '/Users/yuyang/Desktop' ]

the command work fine, however in claude it failed with this

2025-03-26T03:53:27.788Z [filesystem] [info] Initializing server...
2025-03-26T03:53:27.794Z [filesystem] [info] Server started and connected successfully
2025-03-26T03:53:27.823Z [filesystem] [info] Message from client: {"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"claude-ai","version":"0.1.0"}},"jsonrpc":"2.0","id":0}
**command not found: /Users/yuyang/Desktop**
2025-03-26T03:53:28.209Z [filesystem] [info] Server transport closed
2025-03-26T03:53:28.209Z [filesystem] [info] Client transport closed
2025-03-26T03:53:28.209Z [filesystem] [info] Server transport closed unexpectedly, this is likely due to the process exiting early. If you are developing this MCP server you can add output to stderr (i.e. `console.error('...')` in JavaScript, `print('...', file=sys.stderr)` in python) and it will appear in this log.
2025-03-26T03:53:28.209Z [filesystem] [error] Server disconnected. For troubleshooting guidance, please visit our [debugging documentation](https://modelcontextprotocol.io/docs/tools/debugging) {"context":"connection"}
2025-03-26T03:53:28.209Z [filesystem] [info] Client transport closed

Same mcp server config work fine in Cursor, just Claude can't connect server.

Close issue, ?

Hi, going to close this one since it seems more related to issues with the app than a bug with a server, but feel free to re-open if needed.

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Could not attach to MCP server filesystem #267

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Could not attach to MCP server filesystem #267

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MikeyBeez commented on Dec 8, 2024

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