diff --git a/packages/toolbox-core/src/toolbox_core/client.py b/packages/toolbox-core/src/toolbox_core/client.py
index 1fcea46c..25a3d267 100644
--- a/packages/toolbox-core/src/toolbox_core/client.py
+++ b/packages/toolbox-core/src/toolbox_core/client.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 
-from asyncio import get_running_loop
 from types import MappingProxyType
 from typing import Any, Awaitable, Callable, Mapping, Optional, Union
 
@@ -194,6 +193,11 @@ async def load_tool(
         # request the definition of the tool from the server
         url = f"{self.__base_url}/api/tool/{name}"
         async with self.__session.get(url, headers=resolved_headers) as response:
+            if not response.ok:
+                error_text = await response.text()
+                raise RuntimeError(
+                    f"API request failed with status {response.status} ({response.reason}). Server response: {error_text}"
+                )
             json = await response.json()
         manifest: ManifestSchema = ManifestSchema(**json)
 
@@ -272,6 +276,11 @@ async def load_toolset(
         # Request the definition of the toolset from the server
         url = f"{self.__base_url}/api/toolset/{name or ''}"
         async with self.__session.get(url, headers=resolved_headers) as response:
+            if not response.ok:
+                error_text = await response.text()
+                raise RuntimeError(
+                    f"API request failed with status {response.status} ({response.reason}). Server response: {error_text}"
+                )
             json = await response.json()
         manifest: ManifestSchema = ManifestSchema(**json)
 
diff --git a/packages/toolbox-core/src/toolbox_core/tool.py b/packages/toolbox-core/src/toolbox_core/tool.py
index ebfa8358..1545ded4 100644
--- a/packages/toolbox-core/src/toolbox_core/tool.py
+++ b/packages/toolbox-core/src/toolbox_core/tool.py
@@ -289,7 +289,7 @@ async def __call__(self, *args: Any, **kwargs: Any) -> str:
             headers=headers,
         ) as resp:
             body = await resp.json()
-            if resp.status < 200 or resp.status >= 300:
+            if not resp.ok:
                 err = body.get("error", f"unexpected status from server: {resp.status}")
                 raise Exception(err)
         return body.get("result", body)