diff --git a/src/browserbase/_models.py b/src/browserbase/_models.py
index 6a3cd1d..8c0e2b7 100644
--- a/src/browserbase/_models.py
+++ b/src/browserbase/_models.py
@@ -93,7 +93,7 @@ class Config(pydantic.BaseConfig):  # pyright: ignore[reportDeprecated]
             extra: Any = pydantic.Extra.allow  # type: ignore
     else:
         model_config: ClassVar[ConfigDict] = ConfigDict(
-            extra="allow", defer_build=coerce_boolean(os.environ.get("DEFER_PYDANTIC_BUILD", "true"))
+            extra="ignore", defer_build=coerce_boolean(os.environ.get("DEFER_PYDANTIC_BUILD", "true"))
         )
 
     def to_dict(