diff --git a/.changeset/puny-meals-sniff.md b/.changeset/puny-meals-sniff.md
new file mode 100644
index 0000000..6f8caed
--- /dev/null
+++ b/.changeset/puny-meals-sniff.md
@@ -0,0 +1,5 @@
+---
+"mcp-handler": patch
+---
+
+Add raw headers to incoming message
diff --git a/src/handler/mcp-api-handler.ts b/src/handler/mcp-api-handler.ts
index 8859984..03c66e8 100644
--- a/src/handler/mcp-api-handler.ts
+++ b/src/handler/mcp-api-handler.ts
@@ -870,6 +870,11 @@ function createFakeIncomingMessage(
   req.method = method;
   req.url = url;
   req.headers = headers;
+  req.rawHeaders = Object.entries(headers).flatMap(([key, value]) => 
+    Array.isArray(value) 
+      ? value.flatMap(v => [key, v]) 
+      : [key, value ?? ""]
+  );
 
   const auth = options.auth || getAuthContext();
   if (auth) {