{"version":"2.1.299","anchor":"reserved-mcp-server-name-message","canonical_anchor":"reserved-mcp-server-name-message","heading":"Clearer messages when an MCP server uses a name or address Claude Code reserves","tier":"notice","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.299\/e\/reserved-mcp-server-name-message","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.299","markdown":"### Clearer messages when an MCP server uses a name or address Claude Code reserves\n\nMCP servers configured with a reserved name or address are now refused with an explicit message saying why\n\n**Unclear.** It is not stated which names and addresses are reserved.\n\n**What**\n\nMCP servers are add-ons that give Claude extra tools. Claude Code already refused servers configured under certain reserved names; it now says so with new wording:\n\n- A server with a reserved name is skipped with a message that it \"is a reserved MCP server name and was not loaded\".\n\n- A server at a reserved address is refused with \"Refused - Claude Code reserves this address for its own use\", and a note that no administrator set this.\n\nThe `managedMcpServers` setting now checks server names with shared rules instead of its own built-in check.\n\n**Why**\n\nIf you give a server a reserved name or address, you now get a clear reason it did not load.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 1\/5\n- Signal: 1\/5\n- Scope: individual\n- Heads-up: no"}