diff --git a/lib/crewai/src/crewai/agents/agent_adapters/openai_agents/openai_agent_tool_adapter.py b/lib/crewai/src/crewai/agents/agent_adapters/openai_agents/openai_agent_tool_adapter.py
index 6096ee5d0..b6cda1009 100644
--- a/lib/crewai/src/crewai/agents/agent_adapters/openai_agents/openai_agent_tool_adapter.py
+++ b/lib/crewai/src/crewai/agents/agent_adapters/openai_agents/openai_agent_tool_adapter.py
@@ -16,6 +16,7 @@ from crewai.agents.agent_adapters.openai_agents.protocols import (
 )
 from crewai.tools import BaseTool
 from crewai.utilities.import_utils import require
+from crewai.utilities.pydantic_schema_utils import add_key_in_dict_recursively
 from crewai.utilities.string_utils import sanitize_tool_name
 
 
@@ -135,7 +136,15 @@ class OpenAIAgentToolAdapter(BaseToolAdapter):
         for tool in tools:
             schema: dict[str, Any] = tool.args_schema.model_json_schema()
 
-            schema.update({"additionalProperties": False, "type": "object"})
+            schema = add_key_in_dict_recursively(
+                schema,
+                key="additionalProperties",
+                value=False,
+                criteria=lambda d: d.get("type") == "object"
+                and "additionalProperties" not in d,
+            )
+
+            schema.update({"type": "object"})
 
             openai_tool: OpenAIFunctionTool = cast(
                 OpenAIFunctionTool,
diff --git a/lib/crewai/src/crewai/utilities/pydantic_schema_utils.py b/lib/crewai/src/crewai/utilities/pydantic_schema_utils.py
index 69354742b..9e1982e44 100644
--- a/lib/crewai/src/crewai/utilities/pydantic_schema_utils.py
+++ b/lib/crewai/src/crewai/utilities/pydantic_schema_utils.py
@@ -378,6 +378,21 @@ def create_model_from_schema(  # type: ignore[no-any-unimported]
     """
     effective_root = root_schema or json_schema
 
+    json_schema = add_key_in_dict_recursively(
+        json_schema,
+        key="additionalProperties",
+        value=False,
+        criteria=lambda d: d.get("type") == "object"
+        and "additionalProperties" not in d,
+    )
+    effective_root = add_key_in_dict_recursively(
+        effective_root,
+        key="additionalProperties",
+        value=False,
+        criteria=lambda d: d.get("type") == "object"
+        and "additionalProperties" not in d,
+    )
+
     if "allOf" in json_schema:
         json_schema = _merge_all_of_schemas(json_schema["allOf"], effective_root)
         if "title" not in json_schema and "title" in (root_schema or {}):