From f0fbfc7fcbc1489177f5c81cad7f49ba88b8244e Mon Sep 17 00:00:00 2001
From: qikaigao <33371207+qikaigao@users.noreply.github.com>
Date: Mon, 14 Apr 2025 00:46:13 -0700
Subject: [PATCH 1/3] StreamableHTTPServerTransport should only check init
 status when there is an sessionId

When using stateless mode, the backend will create a new transport for each request. For new transport, the initialized filed is always false. So we should only check the initialized filed if there is session existing
---
 src/server/streamableHttp.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/server/streamableHttp.ts b/src/server/streamableHttp.ts
index ec8d2aa73..fc13e7620 100644
--- a/src/server/streamableHttp.ts
+++ b/src/server/streamableHttp.ts
@@ -371,7 +371,7 @@ export class StreamableHTTPServerTransport implements Transport {
    * Returns true if the session is valid, false otherwise
    */
   private validateSession(req: IncomingMessage, res: ServerResponse): boolean {
-    if (!this._initialized) {
+    if (this.sessionId && !this._initialized) {
       // If the server has not been initialized yet, reject all requests
       res.writeHead(400).end(JSON.stringify({
         jsonrpc: "2.0",

From 0058c30032991cbc8d9e26ac7430d5a9dc442015 Mon Sep 17 00:00:00 2001
From: qikaigao <33371207+qikaigao@users.noreply.github.com>
Date: Thu, 17 Apr 2025 11:08:34 -0700
Subject: [PATCH 2/3] Update src/server/streamableHttp.ts

Co-authored-by: Cliff Hall <cliff@futurescale.com>
---
 src/server/streamableHttp.ts | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/server/streamableHttp.ts b/src/server/streamableHttp.ts
index 78f3dcc54..a388b4ee3 100644
--- a/src/server/streamableHttp.ts
+++ b/src/server/streamableHttp.ts
@@ -463,7 +463,12 @@ export class StreamableHTTPServerTransport implements Transport {
    * Returns true if the session is valid, false otherwise
    */
   private validateSession(req: IncomingMessage, res: ServerResponse): boolean {
-    if (this.sessionId && !this._initialized) {
+    if (this.sessionId === undefined) {
+      // If the session ID is not set, the session management is disabled
+      // and we don't need to validate the session ID
+      return true;
+    }
+    if (!this._initialized) {
       // If the server has not been initialized yet, reject all requests
       res.writeHead(400).end(JSON.stringify({
         jsonrpc: "2.0",

From 1df348710b78746126391c02ff27d93ceb24d688 Mon Sep 17 00:00:00 2001
From: qikaigao <33371207+qikaigao@users.noreply.github.com>
Date: Thu, 17 Apr 2025 15:38:12 -0700
Subject: [PATCH 3/3] Update streamableHttp.ts

---
 src/server/streamableHttp.ts | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/server/streamableHttp.ts b/src/server/streamableHttp.ts
index a388b4ee3..dfaeed7bc 100644
--- a/src/server/streamableHttp.ts
+++ b/src/server/streamableHttp.ts
@@ -480,11 +480,7 @@ export class StreamableHTTPServerTransport implements Transport {
       }));
       return false;
     }
-    if (this.sessionId === undefined) {
-      // If the session ID is not set, the session management is disabled
-      // and we don't need to validate the session ID
-      return true;
-    }
+
     const sessionId = req.headers["mcp-session-id"];
 
     if (!sessionId) {