{"version":"2.1.274","anchor":"mcp-server-add-now-rejects-host-only-transport-types-expli","canonical_anchor":"mcp-server-add-now-rejects-host-only-transport-types-expli","heading":"sse-ide and ws-ide MCP server types are now treated as host-only","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.274\/e\/mcp-server-add-now-rejects-host-only-transport-types-expli","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.274","markdown":"### sse-ide and ws-ide MCP server types are now treated as host-only\n\nClaude Code now blocks adding sse-ide\/ws-ide (and sdk) MCP servers to config and routes them into the blocked list during server-set updates, since these are managed by the host app, not stored config.\n\n**What**\n\n- Adding an MCP server via config now checks its transport type against a host-only set (`sdk`, `sse-ide`, `ws-ide`) and throws a clear error explaining that such servers are registered by the host application at runtime and can't be stored in configuration.\n\n- When processing an `mcp_set_servers` update, servers of type `sse-ide` or `ws-ide` are now routed into the blocked\/dropped map alongside already-registered names, instead of falling through to the general allow\/block logic.\n\n**Why** These transport types represent servers that only make sense as live, host-managed connections (such as an IDE's own SSE\/WebSocket endpoint), so storing or generally allow\/block-listing them as regular config entries doesn't make sense; this change makes that restriction explicit and consistent.\n\n- Area: MCP\n- Names: `sdk`, `sse-ide`, `ws-ide`\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5"}