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MCP Timezone Planner in Claude Desktop

Find meeting slots inside everyone's working hours. It converts times between IANA zones with DST read from the ICU data in your Node build, ranks meeting slots where every participant is inside their own working hours, computes the daily overlap and clock changes, and writes .ics files.

This is the client that is open when the question arrives, which is what contacts_list is for: "who is awake right now" answers from the five contacts you saved, with each one's local time and whether they are inside their working hours.

What you get in Claude Desktop

You say	Tool
Find an hour next week for me in Warsaw, my client in New York and my designer in London.	`find_meeting_slots`
When are Warsaw and New York both at work?	`overlap`
Write me the .ics for Thursday 3pm Warsaw, 45 minutes.	`ics_create`

Warsaw and New York on 09:00 to 17:00 days share 2 hours on 2026-09-10 and 3 hours on 2026-03-16, because the United States moves to daylight time on 8 March and Europe on 29 March. The overlap is computed on a real date, so it says so.

Install it in Claude Desktop

The file is claude_desktop_config.json, and the key inside it is mcpServers.

Scope	Path
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Windows	`%APPDATA%\Claude\claude_desktop_config.json`

One click, with no JSON. Download timezone.mcpb from the bundle catalog and open it. Claude Desktop installs it as an extension and runs it on the Node runtime it ships with, so neither your PATH nor your node version comes into it, and there is no file to edit. Everything below is the manual route, for when you want the entry in the config file itself.

The config block, which needs both strings absolute:

{
  "mcpServers": {
    "timezone": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-servers/servers/timezone/dist/index.js"]
    }
  }
}

If node came from nvm, asdf or homebrew, use the absolute path that which node prints rather than the bare word, because a stdio server started by this app inherits a limited PATH:

"command": "/Users/you/.nvm/versions/node/v22.14.0/bin/node"

The node command above wants a built file. From a clone, once:

git clone https://github.com/theluckystrike/mcp-servers.git
cd mcp-servers && npm install
npm run build -w packages/mcp-license -w servers/timezone

That writes servers/timezone/dist/index.js, and its absolute path is the one argument the config needs.

The npm packages are not published yet, so the form below returns a 404 today. It is here because it is what the entry becomes the day the publish lands, with nothing else changed:

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

Save, then completely quit Claude Desktop and start it again. A window reload is not enough.

Nothing is published to npm yet, so the working install paths are the ones above: the .mcpb bundle from the bundle catalog, a clone and build, or the hosted URL.

No install: the hosted endpoint

The same server runs at https://mcp.zovo.one/mcp/timezone over MCP streamable HTTP, no install. Mint a free token with curl https://mcp.zovo.one/mcp/token, or use a Pro key. It has no filesystem, so a file comes back as a one-hour download link.

{
  "mcpServers": {
    "timezone": {
      "url": "https://mcp.zovo.one/mcp/timezone",
      "headers": { "Authorization": "Bearer <token>" }
    }
  }
}

Claude Desktop notes worth knowing first

Two documented facts decide whether the entry works: every path in claude_desktop_config.json must be absolute, and a stdio server started here inherits only a limited, platform-dependent subset of environment variables. If node came from nvm or homebrew, paste what `which node` prints instead of the bare word. The .mcpb route avoids both: Claude Desktop ships a built-in Node.js environment.

Free: conversions, overlap, DST and business days unlimited; slots for 3 participants over 5 days, 5 contacts, 3 ics a month. Pro is $19 once, verified offline.

Questions

Where is claude_desktop_config.json?

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json. Windows: %APPDATA%\Claude\claude_desktop_config.json. There is no published Linux path. Settings, Developer, Edit Config opens the right copy and creates it if it does not exist.

I added it and MCP Timezone Planner does not appear.

In order: did you fully quit and restart, not just close the window? Is every path absolute? And is the command resolvable, given the limited environment a stdio server inherits here? If node came from nvm, paste what which node prints.

Can I install it without editing JSON?

Yes. An .mcpb bundle, the format renamed from .dxt, opens with Claude and shows an installation dialog. One you built yourself goes in through Settings, Extensions, Advanced settings, Install Extension.

MCP Timezone Planner in detail · The same server in Claude.ai and Claude Desktop connectors and Claude Code · Every server in Claude Desktop · Guides · Claude Desktop docs · Buy Pro

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Find a meeting time across time zones without doing the arithmetic · Read a .ics calendar in Claude: free and busy, conflicts, and billable meetings