diff --git a/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py b/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
index 5a49b8aa1244b..12aeb4e68b61b 100644
--- a/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
+++ b/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
@@ -10,6 +10,7 @@ from collections import defaultdict
 from collections.abc import Iterator
 from concurrent.futures import Future, ThreadPoolExecutor
 from dataclasses import dataclass
+from importlib import metadata
 from typing import TYPE_CHECKING, Any, Optional
 
 import msgspec
@@ -41,17 +42,23 @@ Transfer = tuple[int, float]  # (xfer_handle, start_time)
 EngineId = str
 ReqId = str
 GET_META_MSG = b"get_meta_msg"
-NIXL_NUM_WORKERS = 32
+NIXL_NUM_WORKERS = 4
 
 logger = init_logger(__name__)
 
 # Lazy import nixl_wrapper to avoid loading nixl_bindings if nixl is not used
 try:
     from nixl._api import nixl_agent as NixlWrapper, nixl_agent_config
+    NIXL_VERSION = metadata.version("nixl")
+    NIXL_major, NIXL_minor, NIXL_patch = map(int, NIXL_VERSION.split("."))
+
+    
 except ImportError:
     logger.warning("NIXL is not available")
     NixlWrapper = None
+    NIXL_VERSION = None
 
+NIXL_NUM_WORKERS
 
 class NixlAgentMetadata(
         msgspec.Struct,
@@ -352,9 +359,8 @@ class NixlConnectorWorker:
     def __init__(self, vllm_config: VllmConfig, engine_id: str):
         if NixlWrapper is None:
             logger.error("NIXL is not available")
-            raise RuntimeError("NIXL is not available")
-        logger.info("Initializing NIXL wrapper")
-        logger.info("Initializing NIXL worker %s", engine_id)
+            raise RuntimeError("NIXL is not available.")
+        logger.info("Initializing NIXL v%s: worker %s", NIXL_VERSION, engine_id)
 
         # Config.
         self.vllm_config = vllm_config
@@ -362,10 +368,10 @@ class NixlConnectorWorker:
 
         # Agent.
         import os
-        if os.getenv("VLLM_USE_NIXL_WORKERS", "0") == "1":
-            config = nixl_agent_config(num_threads=NIXL_NUM_WORKERS)
-        else:
-            config = None
+        NIXL_NUM_WORKERS = int(os.getenv("VLLM_NIXL_NUM_WORKERS", "1"))
+        logger.info(f"Using NIXL_NUM_WORKERS={NIXL_NUM_WORKERS} for NIXL agent.")
+
+        config = nixl_agent_config(enable_prog_thread=False, num_threads=NIXL_NUM_WORKERS)
         self.nixl_wrapper = NixlWrapper(str(uuid.uuid4()), config)
         # Map of engine_id -> {rank0: agent_name0, rank1: agent_name1..}.
         self._remote_agents: dict[EngineId, dict[int, str]] = defaultdict(dict)
@@ -454,7 +460,8 @@ class NixlConnectorWorker:
 
     def __del__(self):
         """Cleanup background threads on destruction."""
-        self._handshake_initiation_executor.shutdown(wait=False)
+        if t_ := getattr(self, "_handshake_initiation_executor", None):
+            t_.shutdown(wait=False)
         if self._nixl_handshake_listener_t:
             self._nixl_handshake_listener_t.join(timeout=0)