diff --git a/litellm/llms/bedrock/common_utils.py b/litellm/llms/bedrock/common_utils.py
index f99f0102d83..a8d2fb9ad72 100644
--- a/litellm/llms/bedrock/common_utils.py
+++ b/litellm/llms/bedrock/common_utils.py
@@ -72,34 +72,42 @@ def remove_custom_field_from_tools(request_body: dict) -> None:
 
 def normalize_json_schema_custom_types_to_object(schema: dict) -> None:
     """
-    In-place: replace JSON Schema ``type: \"custom\"`` with ``\"object\"`` recursively.
+    In-place: replace JSON Schema ``type: \"custom\"`` with ``\"object`` (iterative walk).
 
     Anthropic / Claude Code use ``custom`` for tool schemas; Bedrock Invoke and
     Bedrock Converse only accept standard JSON Schema type strings.
-    """
 
-    def _fix_schema(node: Any) -> None:
+    Uses an explicit stack (not recursion) to satisfy recursive-function guards in CI.
+    """
+    stack: List[Any] = [schema]
+    seen: set[int] = set()
+    while stack:
+        node = stack.pop()
         if not isinstance(node, dict):
-            return
+            continue
+        node_id = id(node)
+        if node_id in seen:
+            continue
+        seen.add(node_id)
         if node.get("type") == "custom":
             node["type"] = "object"
         items = node.get("items")
         if isinstance(items, dict):
-            _fix_schema(items)
+            stack.append(items)
         addl = node.get("additionalProperties")
         if isinstance(addl, dict):
-            _fix_schema(addl)
+            stack.append(addl)
         props = node.get("properties")
         if isinstance(props, dict):
             for sub in props.values():
-                _fix_schema(sub)
+                if isinstance(sub, dict):
+                    stack.append(sub)
         for combiner in ("allOf", "anyOf", "oneOf"):
             arr = node.get(combiner)
             if isinstance(arr, list):
                 for sub in arr:
-                    _fix_schema(sub)
-
-    _fix_schema(schema)
+                    if isinstance(sub, dict):
+                        stack.append(sub)
 
 
 def normalize_tool_input_schema_types_for_bedrock_invoke(request_body: dict) -> None: