diff --git a/src/server/types.ts b/src/server/types.ts
index b19879a94920f..e666722f50d47 100644
--- a/src/server/types.ts
+++ b/src/server/types.ts
@@ -20,6 +20,7 @@ declare namespace ts.server {
         gc?(): void;
         trace?(s: string): void;
         require?(initialPath: string, moduleName: string): ModuleImportResult;
+        /*@internal*/
         importServicePlugin?(root: string, moduleName: string): Promise<ModuleImportResult>;
     }
 }
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 5a0a1e2782c5d..2544ef8fc6884 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -7044,7 +7044,6 @@ declare namespace ts.server {
         gc?(): void;
         trace?(s: string): void;
         require?(initialPath: string, moduleName: string): ModuleImportResult;
-        importServicePlugin?(root: string, moduleName: string): Promise<ModuleImportResult>;
     }
 }
 declare namespace ts.server {