diff --git a/release-notes.txt b/release-notes.txt
index 3a43519..f97115a 100644
--- a/release-notes.txt
+++ b/release-notes.txt
@@ -11,6 +11,7 @@ Release notes:
     - adds TaskSeq.chunkBy, chunkByAsync, #345
     - adds TaskSeq.threadState, threadStateAsync, #345
     - adds docs/ with fsdocs-based documentation site covering generating, transforming, consuming, combining and advanced operations
+    - docs: adds missing XML <returns> documentation tags to singleton, isEmpty, length, lengthOrMax, lengthBy, and lengthByAsync
     - test: adds 70 new tests to TaskSeq.Fold.Tests.fs covering call-count assertions, folder-not-called-on-empty, ordering, null initial state, and fold/foldAsync equivalence
 
 0.7.0
diff --git a/src/FSharp.Control.TaskSeq/TaskSeq.fsi b/src/FSharp.Control.TaskSeq/TaskSeq.fsi
index ca3a19d..f914048 100644
--- a/src/FSharp.Control.TaskSeq/TaskSeq.fsi
+++ b/src/FSharp.Control.TaskSeq/TaskSeq.fsi
@@ -102,6 +102,7 @@ type TaskSeq =
     /// </summary>
     ///
     /// <param name="value">The input item to use as the single item of the task sequence.</param>
+    /// <returns>A task sequence containing exactly one element.</returns>
     static member singleton: value: 'T -> TaskSeq<'T>
 
     /// <summary>
@@ -152,6 +153,7 @@ type TaskSeq =
     /// </summary>
     ///
     /// <param name="source">The input task sequence.</param>
+    /// <returns>A task returning <c>true</c> if the sequence contains no elements; <c>false</c> otherwise.</returns>
     /// <exception cref="T:ArgumentNullException">Thrown when the input task sequence is null.</exception>
     static member isEmpty: source: TaskSeq<'T> -> Task<bool>
 
@@ -161,6 +163,7 @@ type TaskSeq =
     /// </summary>
     ///
     /// <param name="source">The input task sequence.</param>
+    /// <returns>A task returning the number of elements in the sequence.</returns>
     /// <exception cref="T:ArgumentNullException">Thrown when the input task sequence is null.</exception>
     static member length: source: TaskSeq<'T> -> Task<int>
 
@@ -172,6 +175,7 @@ type TaskSeq =
     ///
     /// <param name="max">Limit at which to stop evaluating source items for finding the length.</param>
     /// <param name="source">The input task sequence.</param>
+    /// <returns>A task returning the actual length of the sequence, or <paramref name="max" /> if the sequence is longer than <paramref name="max" />.</returns>
     /// <exception cref="T:ArgumentNullException">Thrown when the input task sequence is null.</exception>
     static member lengthOrMax: max: int -> source: TaskSeq<'T> -> Task<int>
 
@@ -183,6 +187,7 @@ type TaskSeq =
     ///
     /// <param name="predicate">A function to test whether an item in the input sequence should be included in the count.</param>
     /// <param name="source">The input task sequence.</param>
+    /// <returns>A task returning the number of elements for which <paramref name="predicate" /> returns <c>true</c>.</returns>
     /// <exception cref="T:ArgumentNullException">Thrown when the input task sequence is null.</exception>
     static member lengthBy: predicate: ('T -> bool) -> source: TaskSeq<'T> -> Task<int>
 
@@ -194,6 +199,7 @@ type TaskSeq =
     ///
     /// <param name="predicate">A function to test whether an item in the input sequence should be included in the count.</param>
     /// <param name="source">The input task sequence.</param>
+    /// <returns>A task returning the number of elements for which <paramref name="predicate" /> returns <c>true</c>.</returns>
     /// <exception cref="T:ArgumentNullException">Thrown when the input task sequence is null.</exception>
     static member lengthByAsync: predicate: ('T -> #Task<bool>) -> source: TaskSeq<'T> -> Task<int>