fix(bedrock): use boto3 client for AWS region detection

src/anthropic/_utils/_utils.py

@@ -181,13 +181,16 @@ def deepcopy_minimal(item: _T) -> _T:
 
     - mappings, e.g. `dict`
     - list
+    - tuple (recursively copies contents)
 
     This is done for performance reasons.
     """
     if is_mapping(item):
         return cast(_T, {k: deepcopy_minimal(v) for k, v in item.items()})
     if is_list(item):
         return cast(_T, [deepcopy_minimal(entry) for entry in item])
+    if isinstance(item, tuple):
+        return cast(_T, tuple(deepcopy_minimal(entry) for entry in item))
     return item
 
 

src/anthropic/lib/bedrock/_client.py

@@ -70,16 +70,22 @@ def _prepare_options(input_options: FinalRequestOptions) -> FinalRequestOptions:
 def _infer_region() -> str:
     """
     Infer the AWS region from the environment variables or
-    from the boto3 session if available.
+    from the boto3 client if available.
     """
     aws_region = os.environ.get("AWS_REGION")
     if aws_region is None:
         try:
             import boto3
-
-            session = boto3.Session()
-            if session.region_name:
-                aws_region = session.region_name
+            import botocore.exceptions
+
+            # Use boto3 client to properly detect region from config/profile
+            try:
+                aws_region = boto3.client("bedrock").meta.region_name
+            except botocore.exceptions.NoRegionError:
+                # Fall back to session-based detection
+                session = boto3.Session()
+                if session.region_name:
+                    aws_region = session.region_name
         except ImportError:
             pass