diff --git a/neo/assistant/api.go b/neo/assistant/api.go
index 7a6ab2c9..b38288fe 100644
--- a/neo/assistant/api.go
+++ b/neo/assistant/api.go
@@ -240,7 +240,7 @@ func (ast *Assistant) streamChat(
 			content.Append(value)
 			if value != "" {
 				// Handle stream
-				res, err := ast.HookStream(c, ctx, messages, content.String(), msg.Type == "tool_calls")
+				res, err := ast.HookStream(c, ctx, messages, content.String(), content.Type == "function")
 				if err == nil && res != nil {
 					if res.Output != "" {
 						value = res.Output
@@ -277,7 +277,7 @@ func (ast *Assistant) streamChat(
 
 				// Call HookDone
 				content.SetStatus(message.ContentStatusDone)
-				res, hookErr := ast.HookDone(c, ctx, messages, content.String(), msg.Type == "tool_calls")
+				res, hookErr := ast.HookDone(c, ctx, messages, content.String(), content.Type == "function")
 				if hookErr == nil && res != nil {
 					if res.Output != "" {
 						chatMessage.New().
diff --git a/neo/message/content.go b/neo/message/content.go
index 972037f3..e79a8f4d 100644
--- a/neo/message/content.go
+++ b/neo/message/content.go
@@ -1,6 +1,8 @@
 package message
 
-import "fmt"
+import (
+	jsoniter "github.com/json-iterator/go"
+)
 
 const (
 	// ContentStatusPending the content status pending
@@ -36,7 +38,32 @@ func NewContent(typ string) *Content {
 // String the content string
 func (c *Content) String() string {
 	if c.Type == "function" {
-		return fmt.Sprintf(`{"id":"%s","type": "function", "function": {"name": "%s", "arguments": "%s"}}`, c.ID, c.Name, c.Bytes)
+
+		var arguments interface{} = string(c.Bytes)
+		if c.Status == ContentStatusDone {
+			var vv interface{} = nil
+			err := jsoniter.Unmarshal(c.Bytes, &vv)
+			if err != nil {
+				return ""
+			}
+			arguments = vv
+		}
+
+		data := map[string]interface{}{
+			"id":   c.ID,
+			"type": "function",
+			"function": map[string]interface{}{
+				"name":      c.Name,
+				"arguments": arguments,
+			},
+		}
+
+		raw, err := jsoniter.MarshalToString(data)
+		if err != nil {
+			return ""
+		}
+
+		return raw
 	}
 	return string(c.Bytes)
 }
diff --git a/neo/message/message.go b/neo/message/message.go
index 72b9c702..97c90ee6 100644
--- a/neo/message/message.go
+++ b/neo/message/message.go
@@ -97,6 +97,7 @@ func NewOpenAI(data []byte) *Message {
 			return msg
 		}
 
+		msg.Type = "text"
 		if len(message.Choices) > 0 {
 			msg.Text = message.Choices[0].Delta.Content
 		}