The mcp login and mcp logout commands require the named MCP server to already be added to your configuration. Add it first with claude mcp add, then authenticate with claude mcp login <name>.
The teammateMode: "iterm2" setting requires both the it2 CLI (pip install it2) and the iTerm2 Python API (Preferences > General > Magic > Enable Python API) to be set up before Claude Code is launched.
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Anthropic's release notes agree
Added claude mcp login <name> and claude mcp logout <name> to authenticate MCP servers from the CLI without opening the interactive /mcp…