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Claude Desktop MCP Config: claude_desktop_config.json Guide

Where claude_desktop_config.json lives on macOS and Windows, its mcpServers shape for local servers, and where a remote Claude Desktop MCP server goes.


Published · Updated · 6 min read

Cover image: Config file or connector?

The Claude Desktop MCP config file, claude_desktop_config.json, lists local servers that Claude Desktop starts on your own computer.

Remote servers, which are just a URL, go in as a custom connector instead. This guide covers the file on macOS and Windows, and where a remote server like Weir fits. We run Weir.

Here is the shape of a local entry, trimmed from the MCP project's docs:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/username/Desktop"]
    }
  }
}

Where is the Claude Desktop config file?

It sits in Claude's app data folder, per the MCP project's guide to local servers:

  • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
  • Windows: %APPDATA%\Claude\claude_desktop_config.json
  1. Open the fileIn Claude's menu, pick Settings, then Developer, then Edit Config. It creates the file if needed.
  2. Add an entryPut each server under mcpServers. Use absolute paths in args.
  3. Quit and reopenQuit Claude Desktop completely. Closing the window doesn't reload the file.
  4. Check the toolsClick + in the chat box, then Connectors. Your server and its tools show there.

Newer builds use a different Settings layout. Anthropic's help center now lists local servers, with their status and logs, under Settings, then Desktop app, then Manage next to Extensions.

Claude Desktop MCP config: what an entry takes

Each key under mcpServers is a name you pick. Its value tells Claude Desktop how to start the server, which then talks to Claude over stdio: the program's standard input and output.

Key What it holds Example
command The program to run npx, uvx or a full path
args Its arguments, as a list the package and folders
env Environment variables it needs an API key

The server runs with your user's permissions. So the filesystem server above can read and change anything in the folders you list.

When something fails, read the logs. They live in ~/Library/Logs/Claude on macOS and %APPDATA%\Claude\logs on Windows.

Can claude_desktop_config.json take a remote MCP server URL?

No. Every entry in this file is a program for Claude Desktop to start, and a remote server isn't a program on your machine.

Anthropic's help center draws the line:

  • Remote connectors are reached "from Anthropic's cloud infrastructure", in every client, Desktop included.
  • Local servers in claude_desktop_config.json are "a separate mechanism" that uses your own network.

One user's logs in a Webflow GitHub issue, from December 2025, show what happens if you try. Claude Desktop treated a url entry as a missing extension, and no sign-in started.

So add Weir as a custom connector: https://api.weirapp.io/mcp. Our Claude connector guide has the steps for each plan. Once added, it works in Desktop, on the web and on mobile.

We ran one X search through our own Weir connector on 24 October 2026:

→ search_x {"fromUsers": ["AnthropicAI"], "query": "-filter:nativeretweets",
            "onlyOriginal": true, "since": "2026-10-01T00:00:00Z", "limit": 1}
← 1 post · 2 credits (1 + 1 × 1) · nextCursor set
  Oct 23  4,187 likes  1,946,478 views  A further analysis of an AISI-reported incident
2credits for our 1-post search
0credits for get_usage
1custom connector on the Free plan
5,000free Weir credits every month

Weir bills 1 credit per call plus 1 per X post, and failed calls are free. See every rate on our pricing page.

Desktop Extensions: local servers without the JSON

Desktop Extensions are .mcpb files: a zip of a local server plus a manifest.json. Anthropic's help center lists two ways in:

  • From the directory. Settings, then Desktop app, then Manage next to Extensions, then Browse extensions.
  • From a file. Same page, then Advanced settings, then Install Extension, and pick the .mcpb.

Node.js comes built in, so Node servers need no install. Fields marked sensitive, like API keys, go to the Keychain on macOS or Credential Manager on Windows.

Extensions are still local servers. The old .dxt format is now .mcpb, per Anthropic's MCPB repository.

Still want a remote server in the file?

Use a local bridge. mcp-remote is a community npm package, not made by Anthropic. Claude Desktop starts it as a local server, and it forwards calls to the remote URL.

{
  "mcpServers": {
    "weir": {
      "command": "npx",
      "args": ["-y", "mcp-remote@0.15.2", "https://api.weirapp.io/mcp"]
    }
  }
}

What it needs, from its README:

  • Node.js 18 or newer. Claude Desktop uses your system's Node, not a newer one elsewhere.
  • A browser, once. It registers with Weir and waits on a localhost port, which Weir accepts. Tokens stay in ~/.mcp-auth.
  • Your trust. It runs as you. We pinned the current version, 0.15.2, so updates don't arrive unread.

It can help when your Free plan's one custom connector is taken, since Anthropic calls local servers a separate mechanism. Otherwise, use the connector: it also covers web and mobile.

What we haven't tested

We can't run Claude Desktop here. This guide comes from Anthropic's and the MCP project's docs, plus a real call through Weir's MCP server.

  • The bridge with Weir. Weir's docs list mcp-remote for local-only clients, but we haven't run it in Claude Desktop.
  • The Free-plan limit. We haven't checked whether a bridged server counts as your one custom connector.

If it doesn't work

  • Nothing loads. Check the JSON. One missing comma breaks the whole file.
  • The server never starts. Run its command and args in a terminal to see the error.
  • ENOENT with ${APPDATA} on Windows. Add APPDATA with its full path under env, as the MCP docs show.
  • Local servers are off. A company can set isLocalDevMcpEnabled to false in Claude Desktop's policy.
  • A url entry does nothing. Move the server to a custom connector, as above.

When not to use Weir

  • Claude has to post, reply or DM. Weir is read-only.
  • You want private data. Weir reads public posts, not your DMs or home timeline.
  • Price per post matters most. TwitterAPI.io lists $0.15 per 1,000 tweets as of October 2026, less than our $5 pack.
  • You need a guarantee. Weir isn't licensed by X or affiliated with it, so access can change.

FAQ

Where is claude_desktop_config.json on Windows?

At %APPDATA%\Claude\claude_desktop_config.json. Paste %APPDATA%\Claude into File Explorer's address bar to open the folder. Or use Edit Config in Claude Desktop's settings, which creates the file if it's missing.

Can I add a remote MCP server to claude_desktop_config.json?

Not directly. The file starts local programs. Add the URL as a custom connector instead, or wrap it in a local bridge like mcp-remote if you accept running community code.

Do connectors added on claude.ai work in Claude Desktop?

Yes. Anthropic says remote connectors are set up through your Claude account. Add one on the web, and Desktop and the mobile apps have it too.

How do I add an MCP server to Claude Desktop?

For a local server, add an entry under mcpServers in the config file and restart, or install a .mcpb extension. For a remote server, add its URL under Customize, then Connectors.

Sources

All checked on 24 October 2026:

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