MCP in Claude Code.
One command, fully explained.

Claude Code speaks MCP natively: one CLI command registers a server, and your agent can use its tools in every session. This guide covers the add command, the three scopes, OAuth sign-in, and the flags people miss, using Amie's calendar and meeting-notes server as the worked example.

Get started

Add a server

Remote HTTP servers are the simplest kind: nothing to install, nothing to keep running. Pass the URL with the HTTP transport flag.

Remote server over HTTP
claude mcp add amie https://mcp.amie.so -t http
Local server (runs a command on your machine)
claude mcp add my-server -- npx -y @some/mcp-server
Local server with environment variables
claude mcp add my-server -e API_KEY=your-key -- npx -y @some/mcp-server

Then start a session and run /mcp. Servers that use OAuth (Amie does) show an authenticate option there; it opens your browser, you approve the sign-in once, and tokens refresh automatically from then on.

Pick the right scope

Every server is registered at one of three scopes, chosen with -s. The default is local, which is rarely what you want for a server you'll use everywhere.

  1. local
    Only you, only this project. The default. Stored in ~/.claude.json under the project's entry.
  2. project
    Written to .mcp.json in the repo root. Commit it and everyone who clones the project gets the same servers. Claude Code asks for approval before using a project's servers for the first time.
  3. user
    Available to you in every project on this machine. The right scope for personal servers like your calendar: claude mcp add amie https://mcp.amie.so -t http -s user

Manage what's connected

List every server and its connection status
claude mcp list
Inspect one server's config
claude mcp get amie
Remove a server
claude mcp remove amie

One thing worth knowing: every connected server's tool definitions load into your context window at session start. A pile of single-purpose servers costs tokens on every request, which is a reason to prefer one server that covers several surfaces. Amie's covers calendar, todos, and meeting notes through a single connection, including Google Calendar across multiple accounts.

When it doesn't connect

  1. 1
    Server shows as failed in /mcp. For local servers, run the command yourself in a terminal first; most failures are a missing binary or a bad path. For remote servers, check you passed -t http. Without it the URL is treated as a command to execute.
  2. 2
    Added the server but Claude can't see the tools. Check the scope. A server added with the default local scope in one project won't exist in another. Re-add with -s user if you want it everywhere.
  3. 3
    OAuth keeps failing or tools return 401. Run /mcp, pick the server, and re-authenticate. If your browser opened but nothing happened, check a popup blocker didn't swallow the consent page.

Questions, answered

Give Claude Code your calendar.

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