Install MCP Skills Claude Desktop Mac: Step-by-Step

Last month I helped a non-technical colleague add a calendar tool to her Claude Desktop. She'd never touched a JSON file before. Ten minutes later, Claude was pulling her meetings automatically. Here's exactly how we did it — including the part where TextEdit almost wrecked everything.

What You'll Need

• Claude Desktop — download from claude.ai/download
• Node.js — download the LTS version from nodejs.org
• A text editor — TextEdit works, but VS Code is much better. Both free.

Step 1: Find the Config File

Claude Desktop keeps its config here on Mac:

~/Library/Application Support/Claude/claude_desktop_config.json

The ~ means your home folder — something like /Users/yourname.

The fast way to open it

In Claude Desktop: go to Claude → Settings → Developer, click "Edit Config". Done — it opens the file directly.

Or in Finder: press ⌘ + Shift + G, paste ~/Library/Application Support/Claude/, press Enter.

Step 2: Open the File

Right-click claude_desktop_config.json → Open With:

• VS Code — best option, shows errors in real time
• TextEdit — built-in, always available

File doesn't exist yet?

Open TextEdit, switch to plain text (Format → Make Plain Text), type {}, and save it as claude_desktop_config.json in the Claude folder. Make sure the filename doesn't end in .txt.

Step 3: Add Your Skill

Here's what the config looks like with one skill added:

{
  "mcpServers": {
    "weather": {
      "command": "npx",
      "args": ["-y", "@trustedskills/weather-mcp"]
    }
  }
}

Adding more skills? Just add them inside mcpServers, separated by commas:

{
  "mcpServers": {
    "weather": {
      "command": "npx",
      "args": ["-y", "@trustedskills/weather-mcp"]
    },
    "calculator": {
      "command": "npx",
      "args": ["-y", "@trustedskills/calculator-mcp"]
    }
  }
}

Every skill's page on TrustedSkills has a "MCP Config" tab with the exact snippet to paste. You don't have to type it manually.

Step 4: Save and Restart

1. Save the file — ⌘ + S
2. Quit Claude Desktop completely — ⌘ + Q (closing the window isn't enough)
3. Reopen Claude Desktop

Claude reads the config only on startup. No restart = no new skills.

Step 5: Confirm It Worked

Open a new conversation. Look for the 🔨 tools icon in the input area, or just ask Claude: "What tools do you have?" Your skill's tools should appear in the list.

Config Locations at a Glance

Troubleshooting

JSON errors

JSON doesn't forgive mistakes. Common ones: missing comma between skills, trailing comma after the last skill, single quotes instead of double. Paste your config into jsonlint.com to find errors instantly.

Skill doesn't show up

• Did you fully quit with ⌘+Q? Just closing the window doesn't work.
• Is Node.js installed? Run node --version in Terminal to check.
• Check the logs: Settings → Developer → MCP Logs

npx not found (nvm users)

If you installed Node.js via nvm, Claude Desktop might not see it. Find your npx path — run which npx in Terminal — then use that full path as the "command" value in your config.

Frequently Asked Questions

Where is the Claude Desktop config file on Mac?

It's at ~/Library/Application Support/Claude/claude_desktop_config.json. The fastest way to open it is through Claude Desktop → Settings → Developer → Edit Config.

Do I need to restart after every change?

Yes — a full restart (⌘+Q then reopen), not just closing the window. Claude Desktop reads its config only at startup.

Can I add multiple skills?

Yes. Add as many as you want inside the mcpServers object, each separated by a comma. There's no practical limit.

Why won't npx work on my Mac?

Usually it's nvm. When Node is installed via nvm, the npx command only appears in PATH for interactive shells — Claude Desktop launches in a non-interactive context and doesn't see it. Fix: use the full path from which npx.