diff --git a/src/services/types.ts b/src/services/types.ts
index d832bca7ce..69e33ce673 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -824,9 +824,16 @@ namespace ts {
     }
 
     export const enum OutliningSpanKind {
+        /** Single or multi-line comments */
         Comment = "comment",
+
+        /** Sections marked by '// #region' and '// #endregion' comments */
         Region = "region",
+
+        /** Declarations and expressions */
         Code = "code",
+
+        /** Contiguous blocks of import declarations */
         Imports = "imports"
     }
 
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 7532c6779f..5d1ef5e7a7 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -4890,9 +4890,13 @@ declare namespace ts {
         kind: OutliningSpanKind;
     }
     enum OutliningSpanKind {
+        /** Single or multi-line comments */
         Comment = "comment",
+        /** Sections marked by '// #region' and '// #endregion' comments */
         Region = "region",
+        /** Declarations and expressions */
         Code = "code",
+        /** Contiguous blocks of import declarations */
         Imports = "imports"
     }
     enum OutputFileType {
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 33e9347f48..211c2fbbdf 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -4890,9 +4890,13 @@ declare namespace ts {
         kind: OutliningSpanKind;
     }
     enum OutliningSpanKind {
+        /** Single or multi-line comments */
         Comment = "comment",
+        /** Sections marked by '// #region' and '// #endregion' comments */
         Region = "region",
+        /** Declarations and expressions */
         Code = "code",
+        /** Contiguous blocks of import declarations */
         Imports = "imports"
     }
     enum OutputFileType {