diff --git a/litellm/proxy/auth/auth_utils.py b/litellm/proxy/auth/auth_utils.py
index 9a6fc95f14..567b8307af 100644
--- a/litellm/proxy/auth/auth_utils.py
+++ b/litellm/proxy/auth/auth_utils.py
@@ -216,22 +216,26 @@ _EXTRA_BANNED_OBSERVABILITY_PARAMS: FrozenSet[str] = frozenset(
 def _build_banned_observability_params() -> FrozenSet[str]:
     """Derive the observability ban list from the canonical allowlist.
 
-    ``_supported_callback_params`` in
+    ``_supported_callback_params`` and ``_request_blocked_callback_params`` in
     ``litellm/litellm_core_utils/initialize_dynamic_callback_params.py`` is
-    the single place that enumerates every observability field
-    integrations resolve from kwargs/metadata. Subtract the small set of
-    informational fields (``_SAFE_CLIENT_CALLBACK_PARAMS``) and union with
-    the extras the canonical allowlist hasn't caught up to yet. New
-    integrations added to the canonical allowlist are banned by default,
-    which is the safe failure mode.
+    the single place that enumerates every observability field integrations
+    resolve from kwargs/metadata, plus fields that integration code explicitly
+    blocks from request-supplied callback params. Subtract the small set of
+    informational fields (``_SAFE_CLIENT_CALLBACK_PARAMS``) and union with the
+    extras the canonical allowlist hasn't caught up to yet. New integrations
+    added to the canonical allowlist are banned by default, which is the safe
+    failure mode.
     """
     from litellm.litellm_core_utils.initialize_dynamic_callback_params import (
+        _request_blocked_callback_params,
         _supported_callback_params,
     )
 
     return (
-        frozenset(_supported_callback_params) - _SAFE_CLIENT_CALLBACK_PARAMS
-    ) | _EXTRA_BANNED_OBSERVABILITY_PARAMS
+        (frozenset(_supported_callback_params) - _SAFE_CLIENT_CALLBACK_PARAMS)
+        | frozenset(_request_blocked_callback_params)
+        | _EXTRA_BANNED_OBSERVABILITY_PARAMS
+    )
 
 
 _BANNED_REQUEST_BODY_PARAMS: Tuple[str, ...] = (
diff --git a/tests/test_litellm/proxy/auth/test_auth_utils.py b/tests/test_litellm/proxy/auth/test_auth_utils.py
index 7c04a4f61f..d1a9d6e893 100644
--- a/tests/test_litellm/proxy/auth/test_auth_utils.py
+++ b/tests/test_litellm/proxy/auth/test_auth_utils.py
@@ -1493,6 +1493,7 @@ def test_observability_ban_covers_canonical_supported_callback_params():
     safe is an explicit decision recorded in
     ``_SAFE_CLIENT_CALLBACK_PARAMS``."""
     from litellm.litellm_core_utils.initialize_dynamic_callback_params import (
+        _request_blocked_callback_params,
         _supported_callback_params,
     )
     from litellm.proxy.auth.auth_utils import (
@@ -1508,3 +1509,8 @@ def test_observability_ban_covers_canonical_supported_callback_params():
             f"informational per-request field; otherwise the derivation will "
             f"ban it automatically."
         )
+    for param in _request_blocked_callback_params:
+        assert param in banned, (
+            f"{param} is in _request_blocked_callback_params but is not banned "
+            "at the proxy request-body boundary."
+        )