Update error messages for timeout errors

packages/smithy-core/.changes/next-release/smithy-core-enhancement-20251124183509.json

@@ -0,0 +1,4 @@
+{
+  "type": "enhancement",
+  "description": "Improved default error message for instances of ClientTimeoutError."
+}

packages/smithy-core/src/smithy_core/aio/client.py

@@ -469,9 +469,7 @@ async def _handle_attempt[I: SerializeableShape, O: DeserializeableShape](
                     )
             except Exception as e:
                 if isinstance(e, self.transport.TIMEOUT_EXCEPTIONS):
-                    raise ClientTimeoutError(
-                        message=f"Client timeout occurred: {e}"
-                    ) from e
+                    raise ClientTimeoutError(message="A timeout error occurred.") from e
                 raise
 
             _LOGGER.debug("Received response: %s", transport_response)

packages/smithy-http/.changes/next-release/smithy-http-enhancement-20251122132342.json

@@ -0,0 +1,4 @@
+{
+  "type": "enhancement",
+  "description": "Improved error messaging for CRT-based timeout errors."
+}

packages/smithy-http/src/smithy_http/aio/crt.py

@@ -187,7 +187,7 @@ async def send(
             return await self._await_response(crt_stream)
         except AwsCrtError as e:
             if e.name in self._TIMEOUT_ERROR_NAMES:
-                raise _CRTTimeoutError() from e
+                raise _CRTTimeoutError(f"CRT {e.name}: {e.message}") from e
             raise
 
     async def _await_response(