diff --git a/xml/System.Buffers/ReadOnlySequenceSegment`1.xml b/xml/System.Buffers/ReadOnlySequenceSegment`1.xml
index 46f37461a5f..8d636e45ad1 100644
--- a/xml/System.Buffers/ReadOnlySequenceSegment`1.xml
+++ b/xml/System.Buffers/ReadOnlySequenceSegment`1.xml
@@ -23,7 +23,7 @@
   </Base>
   <Interfaces />
   <Docs>
-    <typeparam name="T">To be added.</typeparam>
+    <typeparam name="T">The type of the elements in the read-only sequence segment.</typeparam>
     <summary>Represents a linked list of <see cref="T:System.ReadOnlyMemory`1" /> nodes.</summary>
     <remarks>To be added.</remarks>
   </Docs>
@@ -47,7 +47,7 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Initializes a new instance of the <see cref="T:System.Buffers.ReadOnlySequenceSegment`1" /> class.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.Buffers/ReadOnlySequence`1.xml b/xml/System.Buffers/ReadOnlySequence`1.xml
index 4972a6db43a..6b3bf5d48db 100644
--- a/xml/System.Buffers/ReadOnlySequence`1.xml
+++ b/xml/System.Buffers/ReadOnlySequence`1.xml
@@ -28,7 +28,7 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <typeparam name="T">To be added.</typeparam>
+    <typeparam name="T">The type of the elements in the read-only sequence.</typeparam>
     <summary>Represents a sequence that can read a sequential series of <typeparamref name="T" />.</summary>
     <remarks>To be added.</remarks>
   </Docs>
@@ -55,7 +55,7 @@
         <Parameter Name="memory" Type="System.ReadOnlyMemory&lt;T&gt;" />
       </Parameters>
       <Docs>
-        <param name="memory">To be added.</param>
+        <param name="memory">A read-only block of memory of elements of type <typeparamref name="T" />.</param>
         <summary>Creates an instance of <see cref="T:System.Buffers.ReadOnlySequence`1" /> from a <see cref="T:System.ReadOnlyMemory`1" />. </summary>
         <remarks>
           <format type="text/markdown"><![CDATA[  
@@ -148,12 +148,23 @@ The consumer is expected to manage the lifetime of memory until <see cref="T:Sys
         <Parameter Name="endIndex" Type="System.Int32" />
       </Parameters>
       <Docs>
-        <param name="startSegment">To be added.</param>
-        <param name="startIndex">To be added.</param>
-        <param name="endSegment">To be added.</param>
-        <param name="endIndex">To be added.</param>
+        <param name="startSegment">The initial node of the linked memory list.</param>
+        <param name="startIndex">The position to the start of the sequence inside <paramref name="startSegment" />.</param>
+        <param name="endSegment">The final node of the linked memory list.</param>
+        <param name="endIndex">The position to the end of the sequence inside <paramref name="endSegment" />.</param>
         <summary>Creates an instance of a <see cref="T:System.Buffers.ReadOnlySequence`1" /> from a linked memory list represented by start and end segments and the corresponding indexes in them.</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="startSegment" /> or <paramref name="endSegment" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentOutOfRangeException">The running index of <paramref name="startSegment" /> is greater than the running index of <paramref name="endSegment" />, even though <paramref name="startSegment" /> is different to <paramref name="endSegment" />.
+
+-or-
+
+<paramref name="startSegment" /> is equal to <paramref name="endSegment" /> but <paramref name="endIndex" /> is smaller than <paramref name="startIndex" />.
+
+-or-
+
+<paramref name="startIndex" /> is greater than the length of the underlying memory block of <paramref name="startSegment" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="Empty">
@@ -178,7 +189,7 @@ The consumer is expected to manage the lifetime of memory until <see cref="T:Sys
         <ReturnType>System.Buffers.ReadOnlySequence&lt;T&gt;</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Returns an empty <see cref="T:System.Buffers.ReadOnlySequence`1" /></summary>
+        <summary>Returns an empty <see cref="T:System.Buffers.ReadOnlySequence`1" />.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -314,9 +325,9 @@ The consumer is expected to manage the lifetime of memory until <see cref="T:Sys
         <Parameter Name="offset" Type="System.Int64" />
       </Parameters>
       <Docs>
-        <param name="offset">To be added.</param>
+        <param name="offset">The offset from the start of the sequence.</param>
         <summary>Returns a new <see cref="T:System.SequencePosition" /> at an <paramref name="offset" /> from the start of the sequence.</summary>
-        <returns>To be added.</returns>
+        <returns>An object representing the sequence position that starts at the specified <paramref name="offset" /> from the start of the sequence.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -346,10 +357,10 @@ The consumer is expected to manage the lifetime of memory until <see cref="T:Sys
         <Parameter Name="origin" Type="System.SequencePosition" />
       </Parameters>
       <Docs>
-        <param name="offset">To be added.</param>
-        <param name="origin">To be added.</param>
-        <summary>Returns a new <see cref="T:System.SequencePosition" /> at an <paramref name="offset" /> from the <paramref name="origin" />.</summary>
-        <returns>A new object that starts at the <paramref name="offset" /> position of the original object.</returns>
+        <param name="offset">The offset from the specified <paramref name="origin" /> sequence position.</param>
+        <param name="origin">A sequence position representing the point from which to initiate the offset.</param>
+        <summary>Returns a new <see cref="T:System.SequencePosition" /> starting at the specified offset from the <paramref name="origin" /> position.</summary>
+        <returns>An object representing the sequence position that starts at the <paramref name="offset" /> position of the specified <paramref name="origin" /> position object.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -778,8 +789,8 @@ The consumer is expected to manage the lifetime of memory until <see cref="T:Sys
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <summary>Returns a string that represents the current sequence.</summary>
+        <returns>A string that represents the current sequence.</returns>
         <remarks>To be added.</remarks>
         <inheritdoc />
       </Docs>