fix(proxy): skip hook-added tag checks where auth skips them and roll back reservations on cancel

The post-hook tag budget check now shares one predicate with the auth wrapper for every request auth never runs common_checks on: public routes, pass-through endpoints without auth, no-auth mode and custom auth without the opt-in. A cancellation while the hook-added tags are being reserved releases the counters already taken instead of leaving them charged.

litellm/proxy/auth/auth_checks.py

@@ -18,7 +18,7 @@ from types import MappingProxyType
 from typing import TYPE_CHECKING, Any, Final, Literal, Optional, Protocol, cast
 
 from fastapi import HTTPException, Request, status
-from pydantic import BaseModel
+from pydantic import BaseModel, TypeAdapter, ValidationError
 from typing_extensions import ReadOnly, TypedDict
 
 import litellm
@@ -133,7 +133,7 @@ from .auth_checks_organization import (
     add_team_org_context_to_request_body,
     organization_role_based_access_check,
 )
-from .auth_utils import get_model_from_request, get_request_route_template
+from .auth_utils import get_model_from_request, get_request_route_template, route_in_additonal_public_routes
 
 if TYPE_CHECKING:
     from opentelemetry.trace import Span as _Span
@@ -863,22 +863,52 @@ def route_skips_budget_checks(route: str) -> bool:
 _AUTHN_FLAGS: Final = ("enable_jwt_auth", "enable_oauth2_auth", "enable_oauth2_proxy_auth")
 
 
+class _PassThroughEndpointAuth(BaseModel):
+    """The two fields of a ``pass_through_endpoints`` entry that decide whether auth runs on it."""
+
+    path: str = ""
+    auth: bool | str | None = None
+
+
+_PASS_THROUGH_ENDPOINTS_ADAPTER: Final = TypeAdapter(tuple[_PassThroughEndpointAuth, ...])
+
+
+def _is_unauthenticated_pass_through(route: str, general_settings: Mapping[str, object]) -> bool:
+    configured: Final = general_settings.get("pass_through_endpoints")
+    if configured is None:
+        return False
+    try:
+        endpoints: Final = _PASS_THROUGH_ENDPOINTS_ADAPTER.validate_python(configured)
+    except ValidationError:
+        return False
+    return any(endpoint.path == route and endpoint.auth is not True for endpoint in endpoints)
+
+
 def auth_skips_common_checks(
-    general_settings: Mapping[str, object], master_key: str | None, custom_auth_configured: bool
+    route: str, general_settings: Mapping[str, object], master_key: str | None, custom_auth_configured: bool
 ) -> bool:
     """
-    Whether ``user_api_key_auth`` runs no ``common_checks`` at all for this deployment.
+    Whether ``user_api_key_auth`` runs no ``common_checks`` at all for this request.
 
-    That is the case in no-auth dev mode (no master key and no JWT or OAuth2
-    auth configured, so the proxy is unauthenticated by configuration) and behind
-    a custom auth hook that did not opt in with ``custom_auth_run_common_checks``.
+    That is the case on a public route, on a user-configured pass-through endpoint
+    that did not ask for auth, in no-auth dev mode (no master key and no JWT or
+    OAuth2 auth configured, so the proxy is unauthenticated by configuration) and
+    behind a custom auth hook that did not opt in with ``custom_auth_run_common_checks``.
     Post-auth checks that mirror ``common_checks`` skip themselves on the same terms.
     """
+    public_route: Final = route in LiteLLMRoutes.public_routes.value or route_in_additonal_public_routes(
+        current_route=route
+    )
     no_auth_mode: Final = master_key is None and not any(general_settings.get(flag, False) for flag in _AUTHN_FLAGS)
     custom_auth_opted_out: Final = custom_auth_configured and not general_settings.get(
         "custom_auth_run_common_checks", False
     )
-    return no_auth_mode or custom_auth_opted_out
+    return (
+        public_route
+        or _is_unauthenticated_pass_through(route=route, general_settings=general_settings)
+        or no_auth_mode
+        or custom_auth_opted_out
+    )
 
 
 async def common_checks(

litellm/proxy/auth/user_api_key_auth.py

@@ -2521,27 +2521,11 @@ async def _run_centralized_common_checks(
         user_custom_auth,
     )
 
-    # Public routes (e.g. /health/liveness) are exempt from
-    # auth in the builder — the wrapper must not retroactively apply
-    # authz on top, or k8s readiness probes and other unauthenticated
-    # callers get 401.
-    if route in LiteLLMRoutes.public_routes.value or route_in_additonal_public_routes(current_route=route):
-        return
-
-    # User-configured pass-through endpoints with ``auth: false`` are
-    # explicitly unauthenticated — the builder returns an empty
-    # UserAPIKeyAuth() and the request is forwarded as-is. Running
-    # common_checks on the empty token would reject the request as
-    # admin-only. The "auth" flag on the endpoint config is the
-    # contract; honor it.
-    pass_through_endpoints: Final = general_settings.get("pass_through_endpoints", None)
-    if pass_through_endpoints is not None:
-        for endpoint in pass_through_endpoints:
-            if isinstance(endpoint, dict) and endpoint.get("path", "") == route and endpoint.get("auth") is not True:
-                return
-
     if auth_skips_common_checks(
-        general_settings=general_settings, master_key=master_key, custom_auth_configured=user_custom_auth is not None
+        route=route,
+        general_settings=general_settings,
+        master_key=master_key,
+        custom_auth_configured=user_custom_auth is not None,
     ):
         return
 

litellm/proxy/common_request_processing.py

@@ -695,7 +695,10 @@ async def _enforce_tag_budgets_for_added_tags(
     from litellm.proxy.proxy_server import master_key, prisma_client, user_api_key_cache, user_custom_auth
 
     if auth_skips_common_checks(
-        general_settings=general_settings, master_key=master_key, custom_auth_configured=user_custom_auth is not None
+        route=route,
+        general_settings=general_settings,
+        master_key=master_key,
+        custom_auth_configured=user_custom_auth is not None,
     ):
         return ()
     await tag_max_budget_check_for_tags(

litellm/proxy/spend_tracking/budget_reservation.py

@@ -360,10 +360,9 @@ async def _reserve_counters(
                         fail_closed_budget_enforcement=fail_closed_budget_enforcement,
                     )
                     continue
-    except Exception:
-        await _release_applied_entries_best_effort(
-            entries=applied_entries,
-            default_reserved_cost=reservation_cost,
+    except BaseException:
+        await asyncio.shield(
+            _release_applied_entries_best_effort(entries=applied_entries, default_reserved_cost=reservation_cost)
         )
         raise
 

tests/test_litellm/proxy/auth/test_auth_checks.py

@@ -2482,27 +2482,60 @@ def test_route_skips_budget_checks_matches_auth_scope(route, expected):
 
 
 @pytest.mark.parametrize(
-    ("general_settings", "master_key", "custom_auth_configured", "expected"),
+    ("route", "general_settings", "master_key", "custom_auth_configured", "expected"),
     [
-        ({}, None, False, True),
-        ({"enable_jwt_auth": True}, None, False, False),
-        ({"enable_oauth2_auth": True}, None, False, False),
-        ({"enable_oauth2_proxy_auth": True}, None, False, False),
-        ({}, "sk-master", False, False),
-        ({}, "sk-master", True, True),
-        ({"custom_auth_run_common_checks": True}, "sk-master", True, False),
-        ({"custom_auth_run_common_checks": False}, "sk-master", True, True),
+        ("/v1/chat/completions", {}, None, False, True),
+        ("/v1/chat/completions", {"enable_jwt_auth": True}, None, False, False),
+        ("/v1/chat/completions", {"enable_oauth2_auth": True}, None, False, False),
+        ("/v1/chat/completions", {"enable_oauth2_proxy_auth": True}, None, False, False),
+        ("/v1/chat/completions", {}, "sk-master", False, False),
+        ("/v1/chat/completions", {}, "sk-master", True, True),
+        ("/v1/chat/completions", {"custom_auth_run_common_checks": True}, "sk-master", True, False),
+        ("/v1/chat/completions", {"custom_auth_run_common_checks": False}, "sk-master", True, True),
+        ("/health/liveliness", {}, "sk-master", False, True),
+        ("/v1/chat/completions", {"public_routes": ["/v1/chat/completions"]}, "sk-master", False, True),
+        ("/v1/chat/completions", {"public_routes": ["/v1/embeddings"]}, "sk-master", False, False),
+        ("/bria", {"pass_through_endpoints": [{"path": "/bria", "target": "https://x"}]}, "sk-master", False, True),
+        (
+            "/bria",
+            {"pass_through_endpoints": [{"path": "/bria", "target": "https://x", "auth": False}]},
+            "sk-master",
+            False,
+            True,
+        ),
+        (
+            "/bria",
+            {"pass_through_endpoints": [{"path": "/bria", "target": "https://x", "auth": True}]},
+            "sk-master",
+            False,
+            False,
+        ),
+        (
+            "/other",
+            {"pass_through_endpoints": [{"path": "/bria", "target": "https://x", "auth": False}]},
+            "sk-master",
+            False,
+            False,
+        ),
     ],
 )
-def test_auth_skips_common_checks_names_the_deployments_that_never_run_them(
-    general_settings, master_key, custom_auth_configured, expected
+def test_auth_skips_common_checks_names_the_requests_that_never_run_them(
+    monkeypatch, route, general_settings, master_key, custom_auth_configured, expected
 ):
-    """No-auth dev mode and a custom auth hook without the opt-in run no common_checks, so no budget checks."""
+    """Public routes, pass-through endpoints without auth, no-auth dev mode and a custom auth hook without
+    the opt-in run no common_checks, so no budget checks."""
+    from litellm.proxy import proxy_server
     from litellm.proxy.auth.auth_checks import auth_skips_common_checks
 
+    monkeypatch.setattr(proxy_server, "general_settings", general_settings)
+    monkeypatch.setattr(proxy_server, "premium_user", True)
+
     assert (
         auth_skips_common_checks(
-            general_settings=general_settings, master_key=master_key, custom_auth_configured=custom_auth_configured
+            route=route,
+            general_settings=general_settings,
+            master_key=master_key,
+            custom_auth_configured=custom_auth_configured,
         )
         is expected
     )

tests/test_litellm/proxy/spend_tracking/test_budget_reservation.py

@@ -1,7 +1,9 @@
 from __future__ import annotations
 
+import asyncio
 import json
 import math
+from collections.abc import Mapping
 from types import MappingProxyType, SimpleNamespace
 from typing import Final
 from unittest.mock import AsyncMock, MagicMock
@@ -139,6 +141,7 @@ async def test_repeated_token_counting_never_touches_a_tiny_budget(
 
 
 HOOK_TAG: Final = "hook-added-tag"
+SECOND_HOOK_TAG: Final = "second-hook-added-tag"
 BODY_TAG: Final = "body-tag"
 CHAT_BODY: Final[dict[str, object]] = {
     "model": "gpt-4o",
@@ -176,11 +179,14 @@ def _budgeted_tag_prisma(tag_names: tuple[str, ...], max_budget: float) -> Magic
 
 
 async def _reserve_added_tags(
-    route: str, prisma: MagicMock, tags: tuple[str, ...] = (HOOK_TAG,)
+    route: str,
+    prisma: MagicMock,
+    tags: tuple[str, ...] = (HOOK_TAG,),
+    request_body: Mapping[str, object] = CHAT_BODY,
 ) -> dict[str, object] | None:
     return await reserve_budget_for_added_tags(
         tags=tags,
-        request_body=dict(CHAT_BODY),
+        request_body=dict(request_body),
         route=route,
         llm_router=None,
         valid_token=UserAPIKeyAuth(token="hashed-hook-tag-key", max_budget=100.0, spend=0.0),
@@ -231,11 +237,63 @@ async def test_reserve_budget_for_added_tags_skips_routes_auth_never_reserves(sp
     assert spend_counter_cache.in_memory_cache.get_cache(key=f"spend:tag:{HOOK_TAG}") is None
 
 
+class _ParkingIncrementCache(DualCache):
+    """A spend-counter cache whose increment of ``parked_key`` never returns, so a test can cancel mid-reservation."""
+
+    def __init__(self, parked_key: str) -> None:
+        super().__init__()
+        self.parked_key: Final = parked_key
+        self.parked: Final = asyncio.Event()
+
+    async def async_increment_cache(self, key: str, value: float, **kwargs: object) -> float | None:
+        if key == self.parked_key:
+            self.parked.set()
+            await asyncio.Event().wait()
+        return await super().async_increment_cache(key=key, value=value, **kwargs)
+
+
+@pytest.mark.asyncio
+async def test_reserve_budget_for_added_tags_releases_the_reserved_tag_when_cancelled_mid_acquisition(
+    monkeypatch: pytest.MonkeyPatch,
+):
+    """A client disconnect under SSE keepalives cancels the request while the second tag is being reserved;
+    the first tag's counter must not stay charged for a request that never reached the provider."""
+    cache: Final = _ParkingIncrementCache(parked_key=f"spend:tag:{SECOND_HOOK_TAG}")
+    monkeypatch.setattr(proxy_server, "spend_counter_cache", cache)
+    monkeypatch.setattr(proxy_server, "prisma_client", None)
+    prisma: Final = _budgeted_tag_prisma((HOOK_TAG, SECOND_HOOK_TAG), max_budget=1.0)
+
+    reserving: Final = asyncio.create_task(
+        _reserve_added_tags("/v1/chat/completions", prisma, tags=(HOOK_TAG, SECOND_HOOK_TAG))
+    )
+    await cache.parked.wait()
+    assert cache.in_memory_cache.get_cache(key=f"spend:tag:{HOOK_TAG}") > 0
+    reserving.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await reserving
+
+    assert cache.in_memory_cache.get_cache(key=f"spend:tag:{HOOK_TAG}") == pytest.approx(0.0)
+
+
 @pytest.mark.asyncio
 async def test_reserve_budget_for_added_tags_ignores_tags_without_a_budget(spend_counter_cache: DualCache):
     assert await _reserve_added_tags("/v1/chat/completions", _budgeted_tag_prisma((), max_budget=1.0)) is None
 
 
+@pytest.mark.asyncio
+async def test_reserve_budget_for_added_tags_skips_a_request_with_no_model_to_price(spend_counter_cache: DualCache):
+    """Without a model there is no estimate to reserve, same as the auth-time reservation."""
+    body: Final = MappingProxyType({key: value for key, value in CHAT_BODY.items() if key != "model"})
+
+    assert (
+        await _reserve_added_tags(
+            "/v1/chat/completions", _budgeted_tag_prisma((HOOK_TAG,), max_budget=1.0), request_body=body
+        )
+        is None
+    )
+    assert spend_counter_cache.in_memory_cache.get_cache(key=f"spend:tag:{HOOK_TAG}") is None
+
+
 BEDROCK_SONNET: Final = "us.anthropic.claude-sonnet-4-6"
 CONVERSE_BODY: Final = {
     "messages": [{"role": "user", "content": [{"text": "Reply with one word: pong"}]}],

tests/test_litellm/proxy/test_common_request_processing.py

@@ -621,13 +621,15 @@ class TestProxyBaseLLMRequestProcessing:
             ("sk-master", object(), {}, False),
             ("sk-master", object(), {"custom_auth_run_common_checks": True}, True),
             ("sk-master", None, {}, True),
+            ("sk-master", None, {"public_routes": ["/v1/chat/completions"]}, False),
+            ("sk-master", None, {"public_routes": ["/v1/embeddings"]}, True),
         ],
     )
     async def test_common_processing_pre_call_logic_enforces_hook_added_tags_only_where_auth_runs_common_checks(
         self, monkeypatch, master_key, user_custom_auth, general_settings, checked
     ):
-        """A deployment whose auth wrapper skips common_checks (no-auth dev mode, custom auth without opt-in)
-        never budget-checked tags before, so a hook-added tag must not start 429ing it."""
+        """A request whose auth wrapper skips common_checks (a public route, no-auth dev mode, custom auth
+        without opt-in) never budget-checked tags before, so a hook-added tag must not start 429ing it."""
         processing_obj = ProxyBaseLLMRequestProcessing(data={})
 
         async def mock_pre_call_hook(user_api_key_dict, data, call_type):
@@ -639,6 +641,8 @@ class TestProxyBaseLLMRequestProcessing:
         )
         monkeypatch.setattr("litellm.proxy.proxy_server.master_key", master_key)
         monkeypatch.setattr("litellm.proxy.proxy_server.user_custom_auth", user_custom_auth)
+        monkeypatch.setattr("litellm.proxy.proxy_server.general_settings", general_settings)
+        monkeypatch.setattr("litellm.proxy.proxy_server.premium_user", True)
 
         await processing_obj.common_processing_pre_call_logic(
             request=mock_request,