diff --git a/sdk/Connection.js b/sdk/Connection.js
index 1557580..d3fbaca 100644
--- a/sdk/Connection.js
+++ b/sdk/Connection.js
@@ -80,11 +80,9 @@ export class Connection {
     }
 
     _onMessage(data) {
-        if (typeof data === 'string') {
-            const parsed = JSON.parse(data);
-            for (const cb of this._packCallbacks) cb(parsed);
-        } else if (data instanceof ArrayBuffer) {
-            // Binary frame — passed raw to WSTSProtocol for codec decoding.
+        // Pass raw wire data to WSTSProtocol; codec.decode() handles parsing.
+        // Pre-parsing here would hand an object to codec.decode which only accepts string/ArrayBuffer.
+        if (typeof data === 'string' || data instanceof ArrayBuffer) {
             for (const cb of this._packCallbacks) cb(data);
         }
     }