diff --git a/.changeset/soft-papayas-hear.md b/.changeset/soft-papayas-hear.md
new file mode 100644
index 000000000..3ea7fcd15
--- /dev/null
+++ b/.changeset/soft-papayas-hear.md
@@ -0,0 +1,7 @@
+---
+"@sei-js/mcp-server": patch
+---
+
+fix:http-server/handlePostMessage
+
+https://github.com/modelcontextprotocol/typescript-sdk/issues/187#issuecomment-2765284408
diff --git a/packages/mcp-server/src/server/http-server.ts b/packages/mcp-server/src/server/http-server.ts
index bdf0a48ef..0e30f9327 100644
--- a/packages/mcp-server/src/server/http-server.ts
+++ b/packages/mcp-server/src/server/http-server.ts
@@ -145,7 +145,7 @@ app.post('/messages', (req: Request, res: Response) => {
 
 	console.error(`Handling message for session: ${sessionId}`);
 	try {
-		transport.handlePostMessage(req, res).catch((error: Error) => {
+		transport.handlePostMessage(req, res, req.body).catch((error: Error) => {
 			console.error(`Error handling post message: ${error}`);
 			res.status(500).json({ error: `Internal server error: ${error.message}` });
 		});