fix: keep body tags visible to _tag_max_budget_check pre-auth

Stripping body-supplied tags in apply_client_tag_policy_pre_auth silently
disabled per-tag budget enforcement for non-opted-in keys — pre-PR
behavior was that those tags reached _tag_max_budget_check inside
common_checks. The post-auth strip in add_litellm_data_to_request
continues to remove unauthorized tags before they leave the proxy.

Also moves the LiteLLMProxyRequestSetup import to module-level (no
circular dep with auth/user_api_key_auth.py).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

litellm/proxy/auth/user_api_key_auth.py

@@ -67,6 +67,7 @@ from litellm.proxy.common_utils.http_parsing_utils import (
     populate_request_with_path_params,
 )
 from litellm.proxy.common_utils.realtime_utils import _realtime_request_body
+from litellm.proxy.litellm_pre_call_utils import LiteLLMProxyRequestSetup
 from litellm.proxy.utils import (
     PrismaClient,
     ProxyLogging,
@@ -1939,13 +1940,10 @@ async def _run_centralized_common_checks(
         llm_router=llm_router,
     )
 
-    # Merge x-litellm-tags (or strip body tags when the key/team has not
-    # opted in via allow_client_tags) into request_data BEFORE common_checks
-    # runs. _tag_max_budget_check inside common_checks only inspects
-    # request_data; without this pre-merge, header-supplied tags bypass
-    # tag-budget enforcement.
-    from litellm.proxy.litellm_pre_call_utils import LiteLLMProxyRequestSetup
-
+    # Merge x-litellm-tags into request_data BEFORE common_checks runs.
+    # _tag_max_budget_check inside common_checks only inspects request_data;
+    # without this pre-merge, header-supplied tags bypass tag-budget
+    # enforcement.
     LiteLLMProxyRequestSetup.apply_client_tag_policy_pre_auth(
         request=request,
         request_data=request_data,

litellm/proxy/litellm_pre_call_utils.py

@@ -1217,15 +1217,12 @@ class LiteLLMProxyRequestSetup:
                 break
 
         if not _admin_allow_client_tags:
-            # Strip any caller-supplied tags so the budget gate doesn't act
-            # on tags this key/team isn't authorized to set. Matches the
-            # post-auth strip in add_litellm_data_to_request.
-            for _meta_key in ("metadata", "litellm_metadata"):
-                _user_meta = request_data.get(_meta_key)
-                if isinstance(_user_meta, dict) and "tags" in _user_meta:
-                    _user_meta.pop("tags", None)
-            if "tags" in request_data:
-                request_data.pop("tags", None)
+            # Don't strip body-supplied tags here — pre-PR behavior was that
+            # _tag_max_budget_check (inside common_checks) saw and enforced
+            # per-tag budgets on body tags regardless of allow_client_tags.
+            # Stripping pre-auth would silently disable that enforcement.
+            # The post-auth strip in add_litellm_data_to_request still
+            # removes unauthorized tags before they leave the proxy.
             return
 
         headers = _safe_get_request_headers(request=request)

tests/test_litellm/proxy/test_litellm_pre_call_utils.py

@@ -4110,7 +4110,14 @@ class TestApplyClientTagPolicyPreAuth:
         # Existing tags first, dedupe header tags
         assert data["metadata"]["tags"] == ["env:prod", "team:platform", "tenant:acme"]
 
-    def test_strips_body_tags_when_not_opted_in(self):
+    def test_preserves_body_tags_when_not_opted_in(self):
+        # Pre-auth must NOT strip body-supplied tags for non-opted-in keys.
+        # _tag_max_budget_check (inside common_checks) enforces per-tag
+        # budgets on whatever tags it sees in request_data, and pre-PR
+        # behavior was that body tags hit that check regardless of
+        # allow_client_tags. The post-auth strip in add_litellm_data_to_request
+        # cleans them up before they leave the proxy — that's covered by a
+        # separate regression test.
         request_mock = _build_request_mock_with_headers(
             {"x-litellm-tags": "tenant:acme"}
         )
@@ -4132,9 +4139,9 @@ class TestApplyClientTagPolicyPreAuth:
             user_api_key_dict=user_api_key_dict,
         )
 
-        assert "tags" not in data
-        assert "tags" not in data["metadata"]
-        assert "tags" not in data["litellm_metadata"]
+        assert data["tags"] == ["root-tag"]
+        assert data["metadata"]["tags"] == ["meta-tag"]
+        assert data["litellm_metadata"]["tags"] == ["litellm-meta-tag"]
 
     def test_does_not_merge_header_tags_when_not_opted_in(self):
         # Even with the header set, no opt-in means the header is ignored