fix: add error handling for missing built-in tools and validate response in stream handler

relay/channel/openai/relay_responses.go

@@ -48,7 +48,12 @@ func OaiResponsesHandler(c *gin.Context, info *relaycommon.RelayInfo, resp *http
 	}
 	// 解析 Tools 用量
 	for _, tool := range responsesResponse.Tools {
-		info.ResponsesUsageInfo.BuiltInTools[common.Interface2String(tool["type"])].CallCount++
+		buildToolinfo, ok := info.ResponsesUsageInfo.BuiltInTools[common.Interface2String(tool["type"])]
+		if !ok {
+			logger.LogError(c, fmt.Sprintf("BuiltInTools not found for tool type: %v", tool["type"]))
+			continue
+		}
+		buildToolinfo.CallCount++
 	}
 	return &usage, nil
 }
@@ -72,7 +77,7 @@ func OaiResponsesStreamHandler(c *gin.Context, info *relaycommon.RelayInfo, resp
 			sendResponsesStreamData(c, streamResponse, data)
 			switch streamResponse.Type {
 			case "response.completed":
-				if streamResponse.Response.Usage != nil {
+				if streamResponse.Response != nil && streamResponse.Response.Usage != nil {
 					if streamResponse.Response.Usage.InputTokens != 0 {
 						usage.PromptTokens = streamResponse.Response.Usage.InputTokens
 					}