diff --git a/docs/spec.md b/docs/spec.md
index 003de16..27a268c 100644
--- a/docs/spec.md
+++ b/docs/spec.md
@@ -574,7 +574,7 @@ function fileserver_download_handler(
 
 ```mermaid
 flowchart TD
-    A[User calls smartsend\(subject, data\)] --> B[Serialize payload according to payload_type]
+    A[User calls smartsend subject data] --> B[Serialize payload according to payload_type]
     B --> C{Calculate serialized size}
     C -->|Size < Threshold| D[Direct Transport: Encode as Base64]
     C -->|Size >= Threshold| E[Link Transport: Upload to file server]