Install an MCP Server in Claude Code on Mac: CLI & Manual Methods

The CLI is the quickest way to add an MCP server to Claude Code on a Mac. It writes the config for you. Editing .mcp.json by hand is useful when you want to review exactly what a project shares with the team.

Prerequisites

• Node.js installed, for servers that run with npx. Check with node --version
• Claude Code: curl -fsSL https://claude.ai/install.sh | bash (or brew install --cask claude-code)

Method 1: CLI (Recommended)

# User scope — available in every project, stored in ~/.claude.json
claude mcp add --scope user memory -- npx -y @modelcontextprotocol/server-memory

# Project scope — written to .mcp.json in the current project
claude mcp add --scope project memory -- npx -y @modelcontextprotocol/server-memory

# With an env variable (API key, etc.)
claude mcp add --scope user brave-search -e BRAVE_API_KEY=yourkey -- npx -y @brave/brave-search-mcp-server

# See what's configured
claude mcp list

# Remove something
claude mcp remove memory

If you leave out --scope, Claude Code uses the local scope: only you, only in the current project.

Method 2: Edit .mcp.json by Hand

For a project server, create .mcp.json in your project root:

code .mcp.json   # opens it in VS Code

{
  "mcpServers": {
    "memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    }
  }
}

Do not hand-edit ~/.claude.json. Claude Code keeps its own state in that file. Use the CLI for user-scoped servers.

The nvm Problem on Mac

nvm sets up Node.js in your shell start-up files. If Claude Code starts from somewhere that does not load them, it may not find the npx that nvm manages.

# Find the full path to npx
which npx
# /Users/yourname/.nvm/versions/node/v20.11.0/bin/npx

{
  "mcpServers": {
    "memory": {
      "command": "/Users/yourname/.nvm/versions/node/v20.11.0/bin/npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"]
    }
  }
}

This path includes the Node.js version. Update it when you change versions with nvm.

Verify It Worked

claude mcp list       # lists configured servers
claude mcp get memory # shows one server and checks that it connects
claude                # start a session
/mcp                  # inside Claude Code: shows each server and its status

Frequently Asked Questions

CLI vs manual editing — which should I use?

Use the CLI for most additions. It writes valid JSON to the right file. Edit .mcp.json by hand when you want to review exactly what the project shares.

How do I add an API key to an MCP server on Mac?

With the CLI: claude mcp add my-server -e API_KEY=abc123 -- npx -y @package/name. In .mcp.json, add an "env" block and use a ${API_KEY} reference instead of the real key.

How do I know a server loaded successfully?

Run claude mcp get <name>. It shows the server and checks the connection. Inside a session, type /mcp to see each server and its status.