Fix Assistant OpenAI adapter to handle message content structure returned by to_hash method

lib/langchain/assistant/llm/adapters/openai.rb

@@ -34,12 +34,19 @@ def build_chat_params(
           # Build a OpenAI message
           #
           # @param role [String] The role of the message
-          # @param content [String] The content of the message
+          # @param content [String | Array<Hash>] The content of the message
           # @param image_url [String] The image URL
           # @param tool_calls [Array] The tool calls
           # @param tool_call_id [String] The tool call ID
           # @return [Messages::OpenAIMessage] The OpenAI message
           def build_message(role:, content: nil, image_url: nil, tool_calls: [], tool_call_id: nil)
+            if content.is_a?(Array)
+              content.each do |c|
+                content = c[:text] if c[:type] == "text"
+                image_url = c[:image_url][:url] if c[:type] == "image_url"
+              end
+            end
+
             Messages::OpenAIMessage.new(role: role, content: content, image_url: image_url, tool_calls: tool_calls, tool_call_id: tool_call_id)
           end
 

spec/langchain/assistant/llm/adapters/openai_spec.rb

@@ -31,4 +31,33 @@
       expect(subject.tool_role).to eq("tool")
     end
   end
+
+  describe "#build_message" do
+    context "when content is a string" do
+      it "returns the OpenAI message" do
+        expect(
+          subject.build_message(
+            role: "user",
+            content: "Hello",
+            image_url: "https://example.com/image.png",
+            tool_calls: [{"id" => "tool_call_id", "function" => {"name" => "langchain_tool_calculator__execute", "arguments" => "{\"a\": 1, \"b\": 2}"}}],
+            tool_call_id: "tool_call_id"
+          )
+        ).to have_attributes(role: "user", content: "Hello", image_url: "https://example.com/image.png", tool_calls: [{"id" => "tool_call_id", "function" => {"name" => "langchain_tool_calculator__execute", "arguments" => "{\"a\": 1, \"b\": 2}"}}], tool_call_id: "tool_call_id")
+      end
+    end
+
+    context "when content is an array" do
+      it "returns the OpenAI message" do
+        expect(
+          subject.build_message(
+            role: "user",
+            content: [{type: "text", text: "Hello"}, {type: "image_url", image_url: {url: "https://example.com/image.png"}}],
+            tool_calls: [{"id" => "tool_call_id", "function" => {"name" => "langchain_tool_calculator__execute", "arguments" => "{\"a\": 1, \"b\": 2}"}}],
+            tool_call_id: "tool_call_id"
+          )
+        ).to have_attributes(role: "user", content: "Hello", image_url: "https://example.com/image.png", tool_calls: [{"id" => "tool_call_id", "function" => {"name" => "langchain_tool_calculator__execute", "arguments" => "{\"a\": 1, \"b\": 2}"}}], tool_call_id: "tool_call_id")
+      end
+    end
+  end
 end