diff --git a/buffet/commands/cloud_command_proxy.cc b/buffet/commands/cloud_command_proxy.cc
index 341401e..4463c50 100644
--- a/buffet/commands/cloud_command_proxy.cc
+++ b/buffet/commands/cloud_command_proxy.cc
@@ -35,7 +35,8 @@
 
 void CloudCommandProxy::OnProgressChanged(int progress) {
   base::DictionaryValue patch;
-  patch.SetInteger(commands::attributes::kCommand_Progress, progress);
+  patch.Set(commands::attributes::kCommand_Progress,
+            command_instance_->GetProgressJson().release());
   // TODO(antonm): Consider batching progress change updates.
   device_registration_info_->UpdateCommand(command_instance_->GetID(), patch);
 }
diff --git a/buffet/commands/command_instance.cc b/buffet/commands/command_instance.cc
index c12f1ed..c67411f 100644
--- a/buffet/commands/command_instance.cc
+++ b/buffet/commands/command_instance.cc
@@ -152,7 +152,8 @@
             TypedValueToJson(parameters_, nullptr).release());
   json->Set(commands::attributes::kCommand_Results,
             TypedValueToJson(results_, nullptr).release());
-  json->SetInteger(commands::attributes::kCommand_Progress, progress_);
+  json->Set(commands::attributes::kCommand_Progress,
+            GetProgressJson().release());
   json->SetString(commands::attributes::kCommand_State, status_);
 
   return json;
@@ -219,5 +220,15 @@
     queue_->DelayedRemove(GetID());
 }
 
+std::unique_ptr<base::Value> CommandInstance::GetProgressJson() const {
+  // GCD server requires "progress" to be a JSON object. We will just make
+  // an object with a single field, "progress", so the patch request will
+  // look like this: {"progress": {"progress":100}}.
+  std::unique_ptr<base::DictionaryValue> progress_object{
+      new base::DictionaryValue};
+  progress_object->SetInteger(commands::attributes::kCommand_Progress,
+                              progress_);
+  return std::move(progress_object);
+}
 
 }  // namespace buffet
diff --git a/buffet/commands/command_instance.h b/buffet/commands/command_instance.h
index 2b09829..e5e0f9f 100644
--- a/buffet/commands/command_instance.h
+++ b/buffet/commands/command_instance.h
@@ -95,6 +95,9 @@
   int GetProgress() const { return progress_; }
   const std::string& GetStatus() const { return status_; }
 
+  // Returns the "progress" portion of JSON command resource.
+  std::unique_ptr<base::Value> GetProgressJson() const;
+
   // Values for command execution status.
   static const char kStatusQueued[];
   static const char kStatusInProgress[];
diff --git a/buffet/commands/command_instance_unittest.cc b/buffet/commands/command_instance_unittest.cc
index 48d54b9..e1d874b 100644
--- a/buffet/commands/command_instance_unittest.cc
+++ b/buffet/commands/command_instance_unittest.cc
@@ -209,7 +209,7 @@
 
   json->MergeDictionary(CreateDictionaryValue(R"({
     'id': 'testId',
-    'progress': 15,
+    'progress': {'progress': 15},
     'state': 'inProgress',
     'results': {'testResult': 17}
   })").get());