diff --git a/packages/toolbox-core/src/toolbox_core/client.py b/packages/toolbox-core/src/toolbox_core/client.py
index 85e8e358..5e6fc042 100644
--- a/packages/toolbox-core/src/toolbox_core/client.py
+++ b/packages/toolbox-core/src/toolbox_core/client.py
@@ -49,7 +49,7 @@ def __init__(
         client_headers: Optional[
             Mapping[str, Union[Callable[[], str], Callable[[], Awaitable[str]], str]]
         ] = None,
-        protocol: Protocol = Protocol.TOOLBOX,
+        protocol: Protocol = Protocol.MCP,
     ):
         """
         Initializes the ToolboxClient.
diff --git a/packages/toolbox-core/tests/test_e2e.py b/packages/toolbox-core/tests/test_e2e.py
index b1275486..3379d7e8 100644
--- a/packages/toolbox-core/tests/test_e2e.py
+++ b/packages/toolbox-core/tests/test_e2e.py
@@ -20,6 +20,7 @@
 from pydantic import ValidationError
 
 from toolbox_core.client import ToolboxClient
+from toolbox_core.protocol import Protocol
 from toolbox_core.tool import ToolboxTool
 
 
@@ -27,7 +28,7 @@
 @pytest_asyncio.fixture(scope="function")
 async def toolbox():
     """Creates a ToolboxClient instance shared by all tests in this module."""
-    toolbox = ToolboxClient("http://localhost:5000")
+    toolbox = ToolboxClient("http://localhost:5000", protocol=Protocol.TOOLBOX)
     try:
         yield toolbox
     finally:
diff --git a/packages/toolbox-core/tests/test_e2e_mcp.py b/packages/toolbox-core/tests/test_e2e_mcp.py
index 9680aa87..996ed407 100644
--- a/packages/toolbox-core/tests/test_e2e_mcp.py
+++ b/packages/toolbox-core/tests/test_e2e_mcp.py
@@ -20,7 +20,6 @@
 from pydantic import ValidationError
 
 from toolbox_core.client import ToolboxClient
-from toolbox_core.protocol import Protocol
 from toolbox_core.tool import ToolboxTool
 
 
@@ -28,7 +27,7 @@
 @pytest_asyncio.fixture(scope="function")
 async def toolbox():
     """Creates a ToolboxClient instance shared by all tests in this module."""
-    toolbox = ToolboxClient("http://localhost:5000", protocol=Protocol.MCP)
+    toolbox = ToolboxClient("http://localhost:5000")
     try:
         yield toolbox
     finally:
diff --git a/packages/toolbox-core/tests/test_sync_e2e.py b/packages/toolbox-core/tests/test_sync_e2e.py
index f2730e47..64da3e5d 100644
--- a/packages/toolbox-core/tests/test_sync_e2e.py
+++ b/packages/toolbox-core/tests/test_sync_e2e.py
@@ -141,7 +141,7 @@ def test_run_tool_wrong_auth(self, toolbox: ToolboxSyncClient, auth_token2: str)
         auth_tool = tool.add_auth_token_getters({"my-test-auth": lambda: auth_token2})
         with pytest.raises(
             Exception,
-            match="tool invocation not authorized",
+            match="Unauthorized",
         ):
             auth_tool(id="2")
 
diff --git a/packages/toolbox-langchain/integration.cloudbuild.yaml b/packages/toolbox-langchain/integration.cloudbuild.yaml
index 0334f9d4..bee3dcb5 100644
--- a/packages/toolbox-langchain/integration.cloudbuild.yaml
+++ b/packages/toolbox-langchain/integration.cloudbuild.yaml
@@ -47,5 +47,5 @@ options:
   logging: CLOUD_LOGGING_ONLY
 substitutions:
   _VERSION: '3.13'
-  _TOOLBOX_VERSION: '0.16.0'
+  _TOOLBOX_VERSION: '0.17.0'
   _TOOLBOX_MANIFEST_VERSION: '34'
diff --git a/packages/toolbox-langchain/tests/test_e2e.py b/packages/toolbox-langchain/tests/test_e2e.py
index ea750c5b..1dbdb3f9 100644
--- a/packages/toolbox-langchain/tests/test_e2e.py
+++ b/packages/toolbox-langchain/tests/test_e2e.py
@@ -143,7 +143,7 @@ async def test_run_tool_wrong_auth(self, toolbox, auth_token2):
         auth_tool = tool.add_auth_token_getter("my-test-auth", lambda: auth_token2)
         with pytest.raises(
             Exception,
-            match="tool invocation not authorized. Please make sure your specify correct auth headers",
+            match="Unauthorized",
         ):
             await auth_tool.ainvoke({"id": "2"})
 
@@ -290,7 +290,7 @@ def test_run_tool_wrong_auth(self, toolbox, auth_token2):
         auth_tool = tool.add_auth_token_getter("my-test-auth", lambda: auth_token2)
         with pytest.raises(
             Exception,
-            match="tool invocation not authorized. Please make sure your specify correct auth headers",
+            match="Unauthorized",
         ):
             auth_tool.invoke({"id": "2"})
 
diff --git a/packages/toolbox-llamaindex/integration.cloudbuild.yaml b/packages/toolbox-llamaindex/integration.cloudbuild.yaml
index 488052f0..836cb7fe 100644
--- a/packages/toolbox-llamaindex/integration.cloudbuild.yaml
+++ b/packages/toolbox-llamaindex/integration.cloudbuild.yaml
@@ -47,5 +47,5 @@ options:
   logging: CLOUD_LOGGING_ONLY
 substitutions:
   _VERSION: '3.13'
-  _TOOLBOX_VERSION: '0.16.0'
+  _TOOLBOX_VERSION: '0.17.0'
   _TOOLBOX_MANIFEST_VERSION: '34'
diff --git a/packages/toolbox-llamaindex/tests/test_e2e.py b/packages/toolbox-llamaindex/tests/test_e2e.py
index 15973fb3..9dbaed6b 100644
--- a/packages/toolbox-llamaindex/tests/test_e2e.py
+++ b/packages/toolbox-llamaindex/tests/test_e2e.py
@@ -143,7 +143,7 @@ async def test_run_tool_wrong_auth(self, toolbox, auth_token2):
         auth_tool = tool.add_auth_token_getter("my-test-auth", lambda: auth_token2)
         with pytest.raises(
             Exception,
-            match="tool invocation not authorized. Please make sure your specify correct auth headers",
+            match="Unauthorized",
         ):
             await auth_tool.acall(id="2")
 
@@ -290,7 +290,7 @@ def test_run_tool_wrong_auth(self, toolbox, auth_token2):
         auth_tool = tool.add_auth_token_getter("my-test-auth", lambda: auth_token2)
         with pytest.raises(
             Exception,
-            match="tool invocation not authorized. Please make sure your specify correct auth headers",
+            match="Unauthorized",
         ):
             auth_tool.call(id="2")