diff --git a/doc/api/fs.md b/doc/api/fs.md
index 9a12289739f64f..abcd7828fb1f6f 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -1023,7 +1023,8 @@ changes:
     that resolves to `true` or `false` **Default:** `undefined`.
     * `src` {string} source path to copy.
     * `dest` {string} destination path to copy to.
-    * Returns: {boolean|Promise}
+    * Returns: {boolean|Promise} A value that is coercible to `boolean` or
+      a `Promise` that fulfils with such value.
   * `force` {boolean} overwrite existing file or directory. The copy
     operation will ignore errors if you set this to false and the destination
     exists. Use the `errorOnExist` option to change this behavior.
@@ -2386,7 +2387,8 @@ changes:
     that resolves to `true` or `false` **Default:** `undefined`.
     * `src` {string} source path to copy.
     * `dest` {string} destination path to copy to.
-    * Returns: {boolean|Promise}
+    * Returns: {boolean|Promise} A value that is coercible to `boolean` or
+      a `Promise` that fulfils with such value.
   * `force` {boolean} overwrite existing file or directory. The copy
     operation will ignore errors if you set this to false and the destination
     exists. Use the `errorOnExist` option to change this behavior.
@@ -5361,7 +5363,8 @@ changes:
     all of its contents will be skipped as well. **Default:** `undefined`
     * `src` {string} source path to copy.
     * `dest` {string} destination path to copy to.
-    * Returns: {boolean}
+    * Returns: {boolean} Any non-`Promise` value that is coercible
+      to `boolean`.
   * `force` {boolean} overwrite existing file or directory. The copy
     operation will ignore errors if you set this to false and the destination
     exists. Use the `errorOnExist` option to change this behavior.