diff --git a/src/mcp-server/cli/start/impl.ts b/src/mcp-server/cli/start/impl.ts
index 231ca0da..b7c4b1ee 100644
--- a/src/mcp-server/cli/start/impl.ts
+++ b/src/mcp-server/cli/start/impl.ts
@@ -50,7 +50,7 @@ async function startStdio(flags: StartCommandFlags) {
     logger,
     allowedTools: flags.tool,
     scopes: flags.scope,
-    ...{ apiKey: flags["api-key"] ?? "" },
+    ...{ apiKey: flags["api-key"] ?? undefined },
     serverURL: flags["server-url"],
     serverIdx: flags["server-index"],
   });
@@ -71,7 +71,7 @@ async function startSSE(flags: StartCommandFlags) {
     logger,
     allowedTools: flags.tool,
     scopes: flags.scope,
-    ...{ apiKey: flags["api-key"] ?? "" },
+    ...{ apiKey: flags["api-key"] ?? undefined },
     serverURL: flags["server-url"],
     serverIdx: flags["server-index"],
   });