fix: preserve Claude reasoning content in message conversions

dto/claude.go

@@ -120,8 +120,9 @@ type ClaudeMessageSource struct {
 }
 
 type ClaudeMessage struct {
-	Role    string `json:"role"`
-	Content any    `json:"content"`
+	Role             string          `json:"role"`
+	Content          any             `json:"content"`
+	ReasoningContent json.RawMessage `json:"reasoning_content,omitempty"`
 }
 
 func (c *ClaudeMessage) IsStringContent() bool {

relay/channel/claude/relay-claude.go

@@ -264,6 +264,9 @@ func RequestOpenAI2ClaudeMessage(c *gin.Context, textRequest dto.GeneralOpenAIRe
 			Role:    message.Role,
 			Content: message.Content,
 		}
+		if message.ReasoningContent != "" {
+			fmtMessage.ReasoningContent = message.ReasoningContent
+		}
 		if message.Role == "tool" {
 			fmtMessage.ToolCallId = message.ToolCallId
 		}
@@ -331,6 +334,13 @@ func RequestOpenAI2ClaudeMessage(c *gin.Context, textRequest dto.GeneralOpenAIRe
 			claudeMessage := dto.ClaudeMessage{
 				Role: message.Role,
 			}
+			if message.ReasoningContent != "" {
+				reasoningContent, err := common.Marshal(message.ReasoningContent)
+				if err != nil {
+					return nil, err
+				}
+				claudeMessage.ReasoningContent = reasoningContent
+			}
 			if message.Role == "tool" {
 				if len(claudeMessages) > 0 && claudeMessages[len(claudeMessages)-1].Role == "user" {
 					lastMessage := claudeMessages[len(claudeMessages)-1]

relay/channel/claude/relay_claude_test.go

@@ -380,3 +380,35 @@ func TestRequestOpenAI2ClaudeMessage_ConvertsTextFileContentToText(t *testing.T)
 	require.NotNil(t, content[0].Text)
 	require.Equal(t, "alpha\nbeta", *content[0].Text)
 }
+
+func TestRequestOpenAI2ClaudeMessagePreservesReasoningContent(t *testing.T) {
+	message := dto.Message{
+		Role:             "assistant",
+		Content:          "",
+		ReasoningContent: " ",
+	}
+	message.SetToolCalls([]dto.ToolCallRequest{
+		{
+			ID:   "call_123",
+			Type: "function",
+			Function: dto.FunctionRequest{
+				Name:      "lookup",
+				Arguments: `{"query":"moonshot"}`,
+			},
+		},
+	})
+	request := dto.GeneralOpenAIRequest{
+		Model:    "kimi-k2-thinking",
+		Messages: []dto.Message{message},
+	}
+
+	claudeRequest, err := RequestOpenAI2ClaudeMessage(nil, request)
+	require.NoError(t, err)
+	require.Len(t, claudeRequest.Messages, 2)
+	require.JSONEq(t, `" "`, string(claudeRequest.Messages[1].ReasoningContent))
+
+	content, ok := claudeRequest.Messages[1].Content.([]dto.ClaudeMediaMessage)
+	require.True(t, ok)
+	require.NotEmpty(t, content)
+	require.Equal(t, "tool_use", content[len(content)-1].Type)
+}

service/convert.go

@@ -134,6 +134,9 @@ func ClaudeToOpenAIRequest(claudeRequest dto.ClaudeRequest, info *relaycommon.Re
 		openAIMessage := dto.Message{
 			Role: claudeMessage.Role,
 		}
+		if len(claudeMessage.ReasoningContent) > 0 {
+			openAIMessage.ReasoningContent = common.JsonRawMessageToString(claudeMessage.ReasoningContent)
+		}
 
 		//log.Printf("claudeMessage.Content: %v", claudeMessage.Content)
 		if claudeMessage.IsStringContent() {