From 75bd8ead7138914e40507cbcf9e13e698041abc0 Mon Sep 17 00:00:00 2001
From: Nick Hill <nhill@redhat.com>
Date: Tue, 22 Jul 2025 18:48:56 +0100
Subject: [PATCH] fix handshake

Signed-off-by: Nick Hill <nhill@redhat.com>
---
 vllm/v1/engine/core.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/vllm/v1/engine/core.py b/vllm/v1/engine/core.py
index 3e15fbbd7589d..4a971e0b3120d 100644
--- a/vllm/v1/engine/core.py
+++ b/vllm/v1/engine/core.py
@@ -523,6 +523,7 @@ class EngineCoreProc(EngineCore):
                              bind=False) as handshake_socket:
             # Register engine with front-end.
             addresses = self.startup_handshake(handshake_socket, local_client,
+                                               headless,
                                                parallel_config_to_update)
             yield addresses
 
@@ -545,6 +546,7 @@ class EngineCoreProc(EngineCore):
     def startup_handshake(
         handshake_socket: zmq.Socket,
         local_client: bool,
+        headless: bool,
         parallel_config: Optional[ParallelConfig] = None,
     ) -> EngineZmqAddresses:
 
@@ -553,6 +555,7 @@ class EngineCoreProc(EngineCore):
             msgspec.msgpack.encode({
                 "status": "HELLO",
                 "local": local_client,
+                "headless": headless,
             }))
 
         # Receive initialization message.