diff --git a/etc/mfm-js.api.md b/etc/mfm-js.api.md
index 6792d39..6aef754 100644
--- a/etc/mfm-js.api.md
+++ b/etc/mfm-js.api.md
@@ -190,7 +190,7 @@ export type MfmSearch = {
 };
 
 // @public (undocumented)
-export type MfmSimpleNode = MfmUnicodeEmoji | MfmEmojiCode | MfmText;
+export type MfmSimpleNode = MfmUnicodeEmoji | MfmEmojiCode | MfmText | MfmPlain;
 
 // @public (undocumented)
 export type MfmSmall = {
diff --git a/src/node.ts b/src/node.ts
index 2f00438..29d8353 100644
--- a/src/node.ts
+++ b/src/node.ts
@@ -1,6 +1,6 @@
 export type MfmNode = MfmBlock | MfmInline;
 
-export type MfmSimpleNode = MfmUnicodeEmoji | MfmEmojiCode | MfmText;
+export type MfmSimpleNode = MfmUnicodeEmoji | MfmEmojiCode | MfmText | MfmPlain;
 
 export type MfmBlock = MfmQuote | MfmSearch | MfmCodeBlock | MfmMathBlock | MfmCenter;