feat: Fill thoughtSignature only for Gemini/Vertex channels using the OpenAI format

relay/channel/gemini/adaptor.go

@@ -177,7 +177,7 @@ func (a *Adaptor) ConvertOpenAIRequest(c *gin.Context, info *relaycommon.RelayIn
 		return nil, errors.New("request is nil")
 	}
 
-	geminiRequest, err := CovertGemini2OpenAI(c, *request, info)
+	geminiRequest, err := CovertOpenAI2Gemini(c, *request, info)
 	if err != nil {
 		return nil, err
 	}

relay/channel/gemini/relay-gemini.go

@@ -44,6 +44,8 @@ var geminiSupportedMimeTypes = map[string]bool{
 	"video/flv":       true,
 }
 
+const thoughtSignatureBypassValue = "context_engineering_is_the_way_to_go"
+
 // Gemini 允许的思考预算范围
 const (
 	pro25MinBudget       = 128
@@ -181,7 +183,7 @@ func ThinkingAdaptor(geminiRequest *dto.GeminiChatRequest, info *relaycommon.Rel
 }
 
 // Setting safety to the lowest possible values since Gemini is already powerless enough
-func CovertGemini2OpenAI(c *gin.Context, textRequest dto.GeneralOpenAIRequest, info *relaycommon.RelayInfo) (*dto.GeminiChatRequest, error) {
+func CovertOpenAI2Gemini(c *gin.Context, textRequest dto.GeneralOpenAIRequest, info *relaycommon.RelayInfo) (*dto.GeminiChatRequest, error) {
 
 	geminiRequest := dto.GeminiChatRequest{
 		Contents: make([]dto.GeminiChatContent, 0, len(textRequest.Messages)),
@@ -193,6 +195,10 @@ func CovertGemini2OpenAI(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 		},
 	}
 
+	attachThoughtSignature := (info.ChannelType == constant.ChannelTypeGemini ||
+		info.ChannelType == constant.ChannelTypeVertexAi) &&
+		model_setting.GetGeminiSettings().FunctionCallThoughtSignatureEnabled
+
 	if model_setting.IsGeminiModelSupportImagine(info.UpstreamModelName) {
 		geminiRequest.GenerationConfig.ResponseModalities = []string{
 			"TEXT",
@@ -371,6 +377,8 @@ func CovertGemini2OpenAI(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 		content := dto.GeminiChatContent{
 			Role: message.Role,
 		}
+		shouldAttachThoughtSignature := attachThoughtSignature && (message.Role == "assistant" || message.Role == "model")
+		signatureAttached := false
 		// isToolCall := false
 		if message.ToolCalls != nil {
 			// message.Role = "model"
@@ -388,6 +396,10 @@ func CovertGemini2OpenAI(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 						Arguments:    args,
 					},
 				}
+				if shouldAttachThoughtSignature && !signatureAttached && hasFunctionCallContent(toolCall.FunctionCall) && len(toolCall.ThoughtSignature) == 0 {
+					toolCall.ThoughtSignature = json.RawMessage(strconv.Quote(thoughtSignatureBypassValue))
+					signatureAttached = true
+				}
 				parts = append(parts, toolCall)
 				tool_call_ids[call.ID] = call.Function.Name
 			}
@@ -496,6 +508,28 @@ func CovertGemini2OpenAI(c *gin.Context, textRequest dto.GeneralOpenAIRequest, i
 	return &geminiRequest, nil
 }
 
+func hasFunctionCallContent(call *dto.FunctionCall) bool {
+	if call == nil {
+		return false
+	}
+	if strings.TrimSpace(call.FunctionName) != "" {
+		return true
+	}
+
+	switch v := call.Arguments.(type) {
+	case nil:
+		return false
+	case string:
+		return strings.TrimSpace(v) != ""
+	case map[string]interface{}:
+		return len(v) > 0
+	case []interface{}:
+		return len(v) > 0
+	default:
+		return true
+	}
+}
+
 // Helper function to get a list of supported MIME types for error messages
 func getSupportedMimeTypesList() []string {
 	keys := make([]string, 0, len(geminiSupportedMimeTypes))

relay/channel/vertex/adaptor.go

@@ -296,7 +296,7 @@ func (a *Adaptor) ConvertOpenAIRequest(c *gin.Context, info *relaycommon.RelayIn
 		info.UpstreamModelName = claudeReq.Model
 		return vertexClaudeReq, nil
 	} else if a.RequestMode == RequestModeGemini {
-		geminiRequest, err := gemini.CovertGemini2OpenAI(c, *request, info)
+		geminiRequest, err := gemini.CovertOpenAI2Gemini(c, *request, info)
 		if err != nil {
 			return nil, err
 		}