diff --git a/tensorboard/data/provider.py b/tensorboard/data/provider.py
index 5df3c944f2..520cc87ae3 100644
--- a/tensorboard/data/provider.py
+++ b/tensorboard/data/provider.py
@@ -227,7 +227,8 @@ def read_scalars(
           plugin_name: String name of the TensorBoard plugin that created
             the data to be queried. Required.
           downsample: Integer number of steps to which to downsample the
-            results (e.g., `1000`). See `DataProvider` class docstring
+            results (e.g., `1000`). The most recent datum (last scalar)
+            should always be included. See `DataProvider` class docstring
             for details about this parameter. Required.
           run_tag_filter: Optional `RunTagFilter` value. If provided, a time
             series will only be included in the result if its run and tag
diff --git a/tensorboard/plugins/hparams/backend_context.py b/tensorboard/plugins/hparams/backend_context.py
index 5d8bd7cebb..e15b5773f6 100644
--- a/tensorboard/plugins/hparams/backend_context.py
+++ b/tensorboard/plugins/hparams/backend_context.py
@@ -190,9 +190,8 @@ def read_last_scalars(self, ctx, experiment_id, run_tag_filter):
             experiment_id=experiment_id,
             plugin_name=scalar_metadata.PLUGIN_NAME,
             run_tag_filter=run_tag_filter,
-            # TODO(#3436): We assume that downsampling always includes
-            # the most recent datum, which holds for all implementations
-            # of interest but is not yet required by the interface.
+            # `read_scalars` always includes the most recent datum, therefore
+            # downsampling to one means fetching the latest value.
             downsample=1,
         )
         return {