diff --git a/messages.go b/messages.go
index eefc29a3..90236393 100644
--- a/messages.go
+++ b/messages.go
@@ -52,10 +52,11 @@ type ImageFile struct {
 }
 
 type MessageRequest struct {
-	Role     string         `json:"role"`
-	Content  string         `json:"content"`
-	FileIds  []string       `json:"file_ids,omitempty"` //nolint:revive // backwards-compatibility
-	Metadata map[string]any `json:"metadata,omitempty"`
+	Role        string             `json:"role"`
+	Content     string             `json:"content"`
+	FileIds     []string           `json:"file_ids,omitempty"` //nolint:revive // backwards-compatibility
+	Metadata    map[string]any     `json:"metadata,omitempty"`
+	Attachments []ThreadAttachment `json:"attachments,omitempty"`
 }
 
 type MessageFile struct {