Complete server warmup before scripted runtime scripts start (#27445)

python/sglang/test/scripted_runtime/http_server.py

@@ -151,12 +151,13 @@ class ScriptedHttpServer:
         # _reset_engine_state, which POSTs to this server's own HTTP port, so
         # block until the port is bound and routing before any script can run.
         #
-        # Wait for *any* HTTP response, not status 200: in scripted mode the
-        # scheduler is driven by the script, so normal warmup never completes
-        # and /health stays 503 (server_status == Starting) for the whole run.
-        # A 503 still proves the socket is bound and routes are registered,
-        # which is all the control POSTs need.
-        url = f"{self._base_url}/health"
+        # Poll /model_info rather than /health: once the server reports Up,
+        # /health runs the generation-based health check (a real probe request
+        # through the scheduler), which cannot complete while the scheduler
+        # waits for scripts between RunScript commands. Any /model_info
+        # response proves the socket is bound and routes are registered, which
+        # is all the control POSTs need.
+        url = f"{self._base_url}/model_info"
         deadline = time.monotonic() + HTTP_READY_TIMEOUT_S
         while time.monotonic() < deadline:
             if not self._server_process.is_alive():