fix: Make a POST request to discover OAuth metadata, not a GET

Author: clareliguori

e2e_tests/python/server_clients/automated_oauth.py

@@ -370,8 +370,8 @@ async def _discover_scope_and_auth_server(self, server_url: str) -> tuple[str, s
 
         async with httpx.AsyncClient() as client:
             headers = {MCP_PROTOCOL_VERSION: LATEST_PROTOCOL_VERSION}
-            response = await client.get(
-                server_url, headers=headers, follow_redirects=True
+            response = await client.post(
+                server_url, headers=headers, follow_redirects=True, json={}
             )
 
             if response.status_code != 401:

e2e_tests/typescript/src/server_clients/automated_oauth.ts

@@ -461,7 +461,13 @@ export class AutomatedOAuthClient extends Server {
     logger.debug("Making initial request to discover OAuth metadata...");
 
     const serverUrl = this.config.serverUrl;
-    const response = await fetch(serverUrl);
+    const response = await fetch(serverUrl, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({}),
+    });
     const resourceMetadataUrl = extractResourceMetadataUrl(response);
 
     if (!resourceMetadataUrl) {