{"version":"2.1.251","anchor":"reserved-mcp-server-names-on-hosted-sessions-must-point-at-a","canonical_anchor":"reserved-mcp-server-names-on-hosted-sessions-must-point-at-a","heading":"Reserved MCP server names on hosted sessions must point at a loopback listener","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.251\/e\/reserved-mcp-server-names-on-hosted-sessions-must-point-at-a","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.251","markdown":"### Reserved MCP server names on hosted sessions must point at a loopback listener\n\nOn hosted sessions, reserved MCP server names must point at a loopback listener.\n\n**What**\n\nOn hosted sessions, where CLAUDE_CODE_REMOTE is set, an MCP server added at runtime whose name matches a reserved set is refused unless it is an http server on a loopback IP address such as `http:\/\/127.0.0.1:PORT\/mcp`. The refusal tells you to point it at the in-container listener or rename the server.\n\n**Details**\n\n- Only reached for dynamically loaded server configs on hosted or remote sessions; local sessions are unaffected.\n- The address must be a literal loopback IP, not a hostname.\n- Which names are reserved is decided by an internal list that this build does not spell out.\n\n**Evidence**\n\n`is reserved except as an http server on a loopback IP literal (e.g. http:\/\/127.0.0.1:PORT\/mcp) and was not loaded`, `on a hosted session is reserved except as an http server on a loopback IP literal (e.g. http:\/\/127.0.0.1:PORT\/mcp) and was not loaded`\n\n- Area: MCP\n- Names: `CLAUDE_CODE_REMOTE`\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 3\/5"}