diff --git a/examples/tutorials/00_sync/010_multiturn/manifest.yaml b/examples/tutorials/00_sync/010_multiturn/manifest.yaml
index c0c7a08f..6b10e48b 100644
--- a/examples/tutorials/00_sync/010_multiturn/manifest.yaml
+++ b/examples/tutorials/00_sync/010_multiturn/manifest.yaml
@@ -114,4 +114,4 @@ deployment:
         memory: "1Gi"
       limits:
         cpu: "1000m"
-        memory: "2Gi" 
\ No newline at end of file
+        memory: "2Gi"
\ No newline at end of file
diff --git a/src/agentex/lib/adk/_modules/acp.py b/src/agentex/lib/adk/_modules/acp.py
index 657f8e14..650fe486 100644
--- a/src/agentex/lib/adk/_modules/acp.py
+++ b/src/agentex/lib/adk/_modules/acp.py
@@ -4,6 +4,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.acp.acp import ACPService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.acp.acp_activities import (
@@ -40,7 +41,7 @@ def __init__(self, acp_service: ACPService | None = None):
             acp_activities (Optional[ACPActivities]): Optional pre-configured ACP activities. If None, will be auto-initialized.
         """
         if acp_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._acp_service = ACPService(agentex_client=agentex_client, tracer=tracer)
         else:
diff --git a/src/agentex/lib/adk/_modules/agent_task_tracker.py b/src/agentex/lib/adk/_modules/agent_task_tracker.py
index 44ffd518..b7385ee1 100644
--- a/src/agentex/lib/adk/_modules/agent_task_tracker.py
+++ b/src/agentex/lib/adk/_modules/agent_task_tracker.py
@@ -3,6 +3,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.agent_task_tracker import AgentTaskTrackerService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.agent_task_tracker_activities import (
@@ -33,7 +34,7 @@ def __init__(
         agent_task_tracker_service: AgentTaskTrackerService | None = None,
     ):
         if agent_task_tracker_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._agent_task_tracker_service = AgentTaskTrackerService(
                 agentex_client=agentex_client, tracer=tracer
diff --git a/src/agentex/lib/adk/_modules/agents.py b/src/agentex/lib/adk/_modules/agents.py
index 5e1bbe0e..b97633c6 100644
--- a/src/agentex/lib/adk/_modules/agents.py
+++ b/src/agentex/lib/adk/_modules/agents.py
@@ -1,6 +1,7 @@
 from datetime import timedelta
 from typing import Optional
 
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.temporal.activities.adk.agents_activities import AgentsActivityName, GetAgentParams
 from temporalio.common import RetryPolicy
 
@@ -28,7 +29,7 @@ def __init__(
         agents_service: Optional[AgentsService] = None,
     ):
         if agents_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._agents_service = AgentsService(agentex_client=agentex_client, tracer=tracer)
         else:
diff --git a/src/agentex/lib/adk/_modules/events.py b/src/agentex/lib/adk/_modules/events.py
index 529db4c3..20817a0a 100644
--- a/src/agentex/lib/adk/_modules/events.py
+++ b/src/agentex/lib/adk/_modules/events.py
@@ -3,6 +3,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.events import EventsService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.events_activities import (
@@ -32,7 +33,7 @@ def __init__(
         events_service: EventsService | None = None,
     ):
         if events_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._events_service = EventsService(
                 agentex_client=agentex_client, tracer=tracer
diff --git a/src/agentex/lib/adk/_modules/messages.py b/src/agentex/lib/adk/_modules/messages.py
index 6d2e2477..51cd0629 100644
--- a/src/agentex/lib/adk/_modules/messages.py
+++ b/src/agentex/lib/adk/_modules/messages.py
@@ -3,6 +3,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.adapters.streams.adapter_redis import RedisStreamRepository
 from agentex.lib.core.services.adk.messages import MessagesService
 from agentex.lib.core.services.adk.streaming import StreamingService
@@ -37,7 +38,7 @@ def __init__(
         messages_service: MessagesService | None = None,
     ):
         if messages_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             stream_repository = RedisStreamRepository()
             streaming_service = StreamingService(
                 agentex_client=agentex_client,
diff --git a/src/agentex/lib/adk/_modules/state.py b/src/agentex/lib/adk/_modules/state.py
index c13a6b59..7759e981 100644
--- a/src/agentex/lib/adk/_modules/state.py
+++ b/src/agentex/lib/adk/_modules/state.py
@@ -5,6 +5,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.state import StateService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.state_activities import (
@@ -36,7 +37,7 @@ def __init__(
         state_service: StateService | None = None,
     ):
         if state_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._state_service = StateService(
                 agentex_client=agentex_client, tracer=tracer
diff --git a/src/agentex/lib/adk/_modules/streaming.py b/src/agentex/lib/adk/_modules/streaming.py
index f604db16..d75fa0f4 100644
--- a/src/agentex/lib/adk/_modules/streaming.py
+++ b/src/agentex/lib/adk/_modules/streaming.py
@@ -1,6 +1,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.adapters.streams.adapter_redis import RedisStreamRepository
 from agentex.lib.core.services.adk.streaming import (
     StreamingService,
@@ -34,7 +35,7 @@ def __init__(self, streaming_service: StreamingService | None = None):
         """
         if streaming_service is None:
             stream_repository = RedisStreamRepository()
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             self._streaming_service = StreamingService(
                 agentex_client=agentex_client,
                 stream_repository=stream_repository,
diff --git a/src/agentex/lib/adk/_modules/tasks.py b/src/agentex/lib/adk/_modules/tasks.py
index 8b8f949a..2b95dd52 100644
--- a/src/agentex/lib/adk/_modules/tasks.py
+++ b/src/agentex/lib/adk/_modules/tasks.py
@@ -3,6 +3,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.tasks import TasksService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.tasks_activities import (
@@ -31,7 +32,7 @@ def __init__(
         tasks_service: TasksService | None = None,
     ):
         if tasks_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._tasks_service = TasksService(
                 agentex_client=agentex_client, tracer=tracer
diff --git a/src/agentex/lib/adk/_modules/tracing.py b/src/agentex/lib/adk/_modules/tracing.py
index 138f25c9..f4073d0e 100644
--- a/src/agentex/lib/adk/_modules/tracing.py
+++ b/src/agentex/lib/adk/_modules/tracing.py
@@ -6,6 +6,7 @@
 from temporalio.common import RetryPolicy
 
 from agentex import AsyncAgentex
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from agentex.lib.core.services.adk.tracing import TracingService
 from agentex.lib.core.temporal.activities.activity_helpers import ActivityHelpers
 from agentex.lib.core.temporal.activities.adk.tracing_activities import (
@@ -38,7 +39,7 @@ def __init__(self, tracing_service: TracingService | None = None):
             tracing_activities (Optional[TracingActivities]): Optional pre-configured tracing activities. If None, will be auto-initialized.
         """
         if tracing_service is None:
-            agentex_client = AsyncAgentex()
+            agentex_client = get_async_agentex_client()
             tracer = AsyncTracer(agentex_client)
             self._tracing_service = TracingService(tracer=tracer)
         else:
diff --git a/src/agentex/lib/adk/utils/_modules/client.py b/src/agentex/lib/adk/utils/_modules/client.py
new file mode 100644
index 00000000..bfe4ad93
--- /dev/null
+++ b/src/agentex/lib/adk/utils/_modules/client.py
@@ -0,0 +1,43 @@
+import threading
+from typing import Dict, Optional, Any
+
+from agentex import AsyncAgentex
+from agentex.lib.environment_variables import EnvironmentVariables, refreshed_environment_variables
+
+_client: Optional["AsyncAgentex"] = None
+_cached_headers: Dict[str, str] = {}
+_init_kwargs: Dict[str, Any] = {}
+_lock = threading.RLock()
+
+
+def _build_headers() -> Dict[str, str]:
+    EnvironmentVariables.refresh()
+    if refreshed_environment_variables and getattr(refreshed_environment_variables, "AGENT_ID", None):
+        return {"x-agent-identity": refreshed_environment_variables.AGENT_ID}
+    return {}
+
+
+def get_async_agentex_client(**kwargs) -> "AsyncAgentex":
+    """
+    Return a cached AsyncAgentex instance (created synchronously).
+    Each call re-checks env vars and updates client.default_headers if needed.
+    """
+    global _client, _cached_headers, _init_kwargs
+
+    new_headers = _build_headers()
+
+    with _lock:
+        # First time (or kwargs changed) -> build a new client
+        if _client is None or kwargs != _init_kwargs:
+            _client = AsyncAgentex(default_headers=new_headers.copy(), **kwargs)
+            _cached_headers = new_headers
+            _init_kwargs = dict(kwargs)
+            return _client
+
+        # Same client; maybe headers changed
+        if new_headers != _cached_headers:
+            _cached_headers = new_headers
+            _client.default_headers.clear()
+            _client.default_headers.update(new_headers)
+
+        return _client
\ No newline at end of file
diff --git a/src/agentex/lib/sdk/fastacp/base/base_acp_server.py b/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
index 8b8cc9ae..c503d5ce 100644
--- a/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
+++ b/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
@@ -2,18 +2,20 @@
 import base64
 import inspect
 import json
+import os
 from collections.abc import AsyncGenerator, Awaitable, Callable
 from contextlib import asynccontextmanager
 from typing import Any
 
 import httpx
 import uvicorn
+from agentex.lib.adk.utils._modules.client import get_async_agentex_client
 from fastapi import FastAPI, Request
 from fastapi.responses import StreamingResponse
 from pydantic import TypeAdapter, ValidationError
 
 # from agentex.lib.sdk.fastacp.types import BaseACPConfig
-from agentex.lib.environment_variables import EnvironmentVariables
+from agentex.lib.environment_variables import EnvironmentVariables, refreshed_environment_variables
 from agentex.lib.types.acp import (
     PARAMS_MODEL_BY_METHOD,
     RPC_SYNC_METHODS,
@@ -390,6 +392,14 @@ async def _register_agent(self, env_vars: EnvironmentVariables):
                         registration_url, json=registration_data, timeout=30.0
                     )
                     if response.status_code == 200:
+                        agent = response.json()
+                        agent_id, agent_name = agent["id"], agent["name"]
+
+                        os.environ["AGENT_ID"] = agent_id
+                        os.environ["AGENT_NAME"] = agent_name
+                        refreshed_environment_variables.AGENT_ID = agent_id
+                        refreshed_environment_variables.AGENT_NAME = agent_name
+                        get_async_agentex_client()  # refresh cache
                         logger.info(
                             f"Successfully registered agent '{env_vars.AGENT_NAME}' with Agentex server with acp_url: {full_acp_url}. Registration data: {registration_data}"
                         )