diff --git a/src/services/types.ts b/src/services/types.ts
index 5dc0955d0d1fa..7224fdbdda8d4 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -718,8 +718,13 @@ namespace ts {
     export interface CompletionEntry {
         name: string;
         kind: ScriptElementKind;
-        kindModifiers: string;
+        kindModifiers: string; // see ScriptElementKindModifier, comma separated
         sortText: string;
+        /**
+         * An optional span that indicates the text to be replaced by this completion item.
+         * If present, this span should be used instead of the default one.
+         * It will be set if the required span differs from the one generated by the default replacement behavior.
+         */
         replacementSpan?: TextSpan;
         hasAction?: true;
         source?: string;