Empty text content should not be set when content is nil when using A…

…nthropicMessage

lib/langchain/assistant/messages/anthropic_message.rb

@@ -53,14 +53,14 @@ def to_hash
         #
         # @return [Hash] The message as an Anthropic API-compatible hash, with the role as "assistant"
         def assistant_hash
+          content_array = []
+          if content && !content.empty?
+            content_array << { type: "text", text: content }
+          end
+
           {
             role: "assistant",
-            content: [
-              {
-                type: "text",
-                text: content
-              }
-            ].concat(tool_calls)
+            content: content_array.concat(tool_calls)
           }
         end
 

spec/langchain/assistant/messages/anthropic_message_spec.rb

@@ -60,6 +60,40 @@
           ]
         )
       end
+
+      it "returns assistant_hash with tool_calls without content" do
+        message = described_class.new(
+          role: role,
+          content: nil,
+          tool_calls: [
+            {
+              "type" => "tool_use",
+              "id" => "toolu_01UEciZACvRZ6S4rqAwD1syH",
+              "name" => "news_retriever__get_everything",
+              "input" => {
+                "q" => "Google I/O 2024",
+                "sort_by" => "publishedAt",
+                "language" => "en"
+              }
+            }
+          ]
+        )
+        expect(message.to_hash).to eq(
+          role: role,
+          content: [
+            {
+              "type" => "tool_use",
+              "id" => "toolu_01UEciZACvRZ6S4rqAwD1syH",
+              "name" => "news_retriever__get_everything",
+              "input" => {
+                "q" => "Google I/O 2024",
+                "sort_by" => "publishedAt",
+                "language" => "en"
+              }
+            }
+          ]
+        )
+      end
     end
 
     context "when role is tool_result" do