diff --git a/tests/test_litellm/conftest.py b/tests/test_litellm/conftest.py
index 4421d227f4e..7b3c0b27842 100644
--- a/tests/test_litellm/conftest.py
+++ b/tests/test_litellm/conftest.py
@@ -10,6 +10,7 @@
 import importlib
 import os
 import sys
+from pathlib import Path
 import pytest
 
 sys.path.insert(
@@ -18,6 +19,75 @@ sys.path.insert(
 import asyncio
 
 import litellm
+from litellm._logging import ALL_LOGGERS
+from litellm.litellm_core_utils.prompt_templates import (
+    image_handling as image_handling_module,
+)
+from litellm.llms.custom_httpx.async_client_cleanup import (
+    close_litellm_async_clients,
+)
+from litellm.proxy.db import tool_registry_writer as tool_registry_writer_module
+
+
+@pytest.fixture(scope="session")
+def isolated_aws_credentials_dir(tmp_path_factory):
+    aws_dir = tmp_path_factory.mktemp("aws-config")
+    credentials_file = Path(aws_dir) / "credentials"
+    config_file = Path(aws_dir) / "config"
+    credentials_file.write_text("", encoding="utf-8")
+    config_file.write_text("", encoding="utf-8")
+    return {
+        "credentials": str(credentials_file),
+        "config": str(config_file),
+    }
+
+
+@pytest.fixture(scope="function", autouse=True)
+def isolate_host_aws_config(monkeypatch, isolated_aws_credentials_dir):
+    """Prevent botocore from reading host AWS profiles during unit tests."""
+    monkeypatch.setenv(
+        "AWS_SHARED_CREDENTIALS_FILE", isolated_aws_credentials_dir["credentials"]
+    )
+    monkeypatch.setenv("AWS_CONFIG_FILE", isolated_aws_credentials_dir["config"])
+    monkeypatch.setenv("AWS_EC2_METADATA_DISABLED", "true")
+    monkeypatch.delenv("AWS_PROFILE", raising=False)
+    monkeypatch.delenv("AWS_DEFAULT_PROFILE", raising=False)
+    monkeypatch.delenv("AWS_CONTAINER_CREDENTIALS_FULL_URI", raising=False)
+    monkeypatch.delenv("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI", raising=False)
+
+
+def _run_coroutine_if_needed(result):
+    if not asyncio.iscoroutine(result):
+        return
+
+    try:
+        asyncio.run(result)
+    except RuntimeError:
+        # If pytest-asyncio already has a running loop, best-effort scheduling is
+        # still better than leaking the client entirely.
+        try:
+            loop = asyncio.get_running_loop()
+        except RuntimeError:
+            return
+        if loop.is_running():
+            loop.create_task(result)
+    except Exception:
+        pass
+
+
+def _close_handler_if_needed(handler):
+    if handler is None:
+        return
+
+    close_fn = getattr(handler, "close", None)
+    if not callable(close_fn):
+        return
+
+    try:
+        result = close_fn()
+        _run_coroutine_if_needed(result)
+    except Exception:
+        pass
 
 
 @pytest.fixture(scope="function", autouse=True)
@@ -44,10 +114,14 @@ def isolate_litellm_state():
         original_state['success_callback'] = litellm.success_callback.copy() if litellm.success_callback else []
     if hasattr(litellm, 'failure_callback'):
         original_state['failure_callback'] = litellm.failure_callback.copy() if litellm.failure_callback else []
+    if hasattr(litellm, 'input_callback'):
+        original_state['input_callback'] = litellm.input_callback.copy() if litellm.input_callback else []
     if hasattr(litellm, '_async_success_callback'):
         original_state['_async_success_callback'] = litellm._async_success_callback.copy() if litellm._async_success_callback else []
     if hasattr(litellm, '_async_failure_callback'):
         original_state['_async_failure_callback'] = litellm._async_failure_callback.copy() if litellm._async_failure_callback else []
+    if hasattr(litellm, '_async_input_callback'):
+        original_state['_async_input_callback'] = litellm._async_input_callback.copy() if litellm._async_input_callback else []
 
     # Store routing globals — leaked model_fallbacks causes tests to route
     # through async_completion_with_fallbacks / Router, bypassing HTTP mocks
@@ -60,9 +134,68 @@ def isolate_litellm_state():
         if hasattr(litellm, _attr):
             original_state[_attr] = getattr(litellm, _attr)
 
+    # Store request-mapping globals that are frequently mutated in tests.
+    if hasattr(litellm, "drop_params"):
+        original_state["drop_params"] = litellm.drop_params
+    if hasattr(litellm, "cache"):
+        original_state["cache"] = litellm.cache
+
+    # Store secret-manager globals. Several tests swap these out, which changes
+    # get_secret() behavior for later env-driven tests (for example Redis config).
+    for _attr in ("secret_manager_client", "_key_management_system", "_key_management_settings"):
+        if hasattr(litellm, _attr):
+            original_state[_attr] = getattr(litellm, _attr)
+
+    # Store other commonly-mutated LiteLLM globals that affect provider routing,
+    # auth, and request shaping during larger suite runs.
+    for _attr in (
+        "api_base",
+        "num_retries",
+        "modify_params",
+        "ssl_verify",
+        "credential_list",
+        "model_group_settings",
+        "default_internal_user_params",
+        "default_team_params",
+        "prometheus_emit_stream_label",
+        "vector_store_registry",
+        "model_cost",
+        "cost_margin_config",
+        "cost_discount_config",
+        "disable_hf_tokenizer_download",
+        "disable_copilot_system_to_assistant",
+        "cohere_models",
+        "anthropic_models",
+        "token_counter",
+        "initialized_langfuse_clients",
+    ):
+        if hasattr(litellm, _attr):
+            original_state[_attr] = getattr(litellm, _attr)
+
+    # Store LiteLLM logger state. Some tests reconfigure handlers/propagation for
+    # JSON logging and do not restore them, which breaks later caplog-based tests.
+    logger_state = {}
+    for logger in ALL_LOGGERS:
+        logger_state[logger.name] = {
+            "level": logger.level,
+            "disabled": logger.disabled,
+            "propagate": logger.propagate,
+            "handlers": list(logger.handlers),
+            "filters": list(logger.filters),
+        }
+
+    # Store singleton registries that are lazily initialized during tests and
+    # can change endpoint behavior later in the suite.
+    original_tool_policy_registry = tool_registry_writer_module._tool_policy_registry
+    had_module_level_client = "module_level_client" in litellm.__dict__
+    had_module_level_aclient = "module_level_aclient" in litellm.__dict__
+    original_module_level_client = litellm.__dict__.get("module_level_client")
+    original_module_level_aclient = litellm.__dict__.get("module_level_aclient")
+
     # Flush cache before test (critical for respx mocks)
     if hasattr(litellm, "in_memory_llm_clients_cache"):
         litellm.in_memory_llm_clients_cache.flush_cache()
+    image_handling_module.in_memory_cache.flush_cache()
 
     # Clear all callback lists to prevent cross-test contamination
     if hasattr(litellm, 'callbacks'):
@@ -71,26 +204,63 @@ def isolate_litellm_state():
         litellm.success_callback = []
     if hasattr(litellm, 'failure_callback'):
         litellm.failure_callback = []
+    if hasattr(litellm, 'input_callback'):
+        litellm.input_callback = []
     if hasattr(litellm, '_async_success_callback'):
         litellm._async_success_callback = []
     if hasattr(litellm, '_async_failure_callback'):
         litellm._async_failure_callback = []
+    if hasattr(litellm, '_async_input_callback'):
+        litellm._async_input_callback = []
 
     # Clear routing globals
     if hasattr(litellm, 'model_fallbacks'):
         litellm.model_fallbacks = None
+    if hasattr(litellm, "cache"):
+        litellm.cache = None
+    litellm.__dict__.pop("module_level_client", None)
+    litellm.__dict__.pop("module_level_aclient", None)
+    tool_registry_writer_module._tool_policy_registry = None
 
     yield
 
     # Cleanup after test
     if hasattr(litellm, "in_memory_llm_clients_cache"):
         litellm.in_memory_llm_clients_cache.flush_cache()
+    image_handling_module.in_memory_cache.flush_cache()
+    current_module_level_client = litellm.__dict__.get("module_level_client")
+    current_module_level_aclient = litellm.__dict__.get("module_level_aclient")
 
     # Restore all callback lists to original state
     for attr_name, original_value in original_state.items():
         if hasattr(litellm, attr_name):
             setattr(litellm, attr_name, original_value)
 
+    # Restore logger configuration mutated by logging-focused tests.
+    for logger in ALL_LOGGERS:
+        original_logger_state = logger_state.get(logger.name)
+        if original_logger_state is None:
+            continue
+        logger.setLevel(original_logger_state["level"])
+        logger.disabled = original_logger_state["disabled"]
+        logger.propagate = original_logger_state["propagate"]
+        logger.handlers = list(original_logger_state["handlers"])
+        logger.filters = list(original_logger_state["filters"])
+
+    tool_registry_writer_module._tool_policy_registry = original_tool_policy_registry
+    if current_module_level_client is not original_module_level_client:
+        _close_handler_if_needed(current_module_level_client)
+    if current_module_level_aclient is not original_module_level_aclient:
+        _close_handler_if_needed(current_module_level_aclient)
+    if had_module_level_client:
+        litellm.__dict__["module_level_client"] = original_module_level_client
+    else:
+        litellm.__dict__.pop("module_level_client", None)
+    if had_module_level_aclient:
+        litellm.__dict__["module_level_aclient"] = original_module_level_aclient
+    else:
+        litellm.__dict__.pop("module_level_aclient", None)
+
 
 @pytest.fixture(scope="module", autouse=True)
 def setup_and_teardown():
@@ -220,3 +390,16 @@ def strict_isolation():
     # Final cache flush
     if hasattr(litellm, "in_memory_llm_clients_cache"):
         litellm.in_memory_llm_clients_cache.flush_cache()
+
+
+def pytest_sessionfinish(session, exitstatus):
+    """Close any globally cached HTTP clients so xdist workers exit cleanly."""
+    _close_handler_if_needed(litellm.__dict__.get("module_level_client"))
+    _close_handler_if_needed(litellm.__dict__.get("module_level_aclient"))
+    litellm.__dict__.pop("module_level_client", None)
+    litellm.__dict__.pop("module_level_aclient", None)
+    _close_handler_if_needed(getattr(litellm, "base_llm_aiohttp_handler", None))
+    _close_handler_if_needed(getattr(litellm, "httpx_client", None))
+    _close_handler_if_needed(getattr(litellm, "aclient", None))
+    _close_handler_if_needed(getattr(litellm, "client", None))
+    _run_coroutine_if_needed(close_litellm_async_clients())
diff --git a/tests/test_litellm/integrations/gitlab/test_gitlab_prompt_manager.py b/tests/test_litellm/integrations/gitlab/test_gitlab_prompt_manager.py
index d623dba0c34..a11c2cd4fa8 100644
--- a/tests/test_litellm/integrations/gitlab/test_gitlab_prompt_manager.py
+++ b/tests/test_litellm/integrations/gitlab/test_gitlab_prompt_manager.py
@@ -87,7 +87,7 @@ def test_gitlab_client_missing_required_fields():
 # GitLabClient: get_file_content
 # -----------------------
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_get_file_content_raw_success(mock_get):
     """Successful file content retrieval via RAW endpoint."""
     mock_response = MagicMock()
@@ -104,7 +104,7 @@ def test_gitlab_client_get_file_content_raw_success(mock_get):
     mock_get.assert_called_once()
 
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_get_file_content_raw_404_fallback_json_base64(mock_get):
     """When RAW returns 404, fallback to JSON endpoint and decode base64 content."""
     import base64
@@ -136,7 +136,7 @@ def test_gitlab_client_get_file_content_raw_404_fallback_json_base64(mock_get):
     assert content == "json-content"
 
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_get_file_content_not_found(mock_get):
     """File not found returns None."""
     # Simulate RAW 404 and JSON 404
@@ -152,7 +152,7 @@ def test_gitlab_client_get_file_content_not_found(mock_get):
     assert content is None
 
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_get_file_content_access_denied(mock_get):
     """403 raises a helpful message."""
     import httpx
@@ -168,7 +168,7 @@ def test_gitlab_client_get_file_content_access_denied(mock_get):
         client.get_file_content("test.prompt")
 
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_get_file_content_auth_failed(mock_get):
     """401 raises auth error."""
     import httpx
@@ -186,7 +186,7 @@ def test_gitlab_client_get_file_content_auth_failed(mock_get):
 # GitLabClient: list_files
 # -----------------------
 
-@patch("litellm.llms.custom_httpx.http_handler.HTTPHandler.get")
+@patch("litellm.integrations.gitlab.gitlab_client.HTTPHandler.get")
 def test_gitlab_client_list_files_success(mock_get):
     """List .prompt files via repository tree API."""
     mock_response = MagicMock()
@@ -817,4 +817,3 @@ def test_cache_get_by_file_returns_exact_entry(mock_pm_cls, fake_managers):
     assert alpha and alpha["id"] == "alpha"
     assert beta and beta["id"] == "nested/beta"
 
-
diff --git a/tests/test_litellm/proxy/client/test_chat.py b/tests/test_litellm/proxy/client/test_chat.py
index 4de58723761..b8e55c45502 100644
--- a/tests/test_litellm/proxy/client/test_chat.py
+++ b/tests/test_litellm/proxy/client/test_chat.py
@@ -1,20 +1,53 @@
-import os
+import importlib
+import importlib.util
+from importlib.machinery import PathFinder
+import site
 import sys
 
 import pytest
 import requests
-
-sys.path.insert(
-    0, os.path.abspath("../../..")
-)  # Adds the parent directory to the system path
-
-
-import responses
-
 from litellm.proxy.client.chat import ChatClient
 from litellm.proxy.client.exceptions import UnauthorizedError
 
 
+def _load_http_mocking_responses():
+    """Load the third-party `responses` package even if test collection creates
+    a top-level `responses` namespace package from `tests/test_litellm/responses`.
+    """
+    module = importlib.import_module("responses")
+    if hasattr(module, "activate"):
+        return module
+
+    for module_name in list(sys.modules):
+        if module_name == "responses" or module_name.startswith("responses."):
+            sys.modules.pop(module_name, None)
+
+    search_paths = []
+    try:
+        search_paths.extend(site.getsitepackages())
+    except AttributeError:
+        pass
+    user_site = site.getusersitepackages()
+    if isinstance(user_site, str):
+        search_paths.append(user_site)
+    else:
+        search_paths.extend(user_site)
+
+    spec = PathFinder.find_spec("responses", search_paths)
+    if spec is None or spec.loader is None:
+        raise ImportError("Unable to load the third-party `responses` package")
+    module = importlib.util.module_from_spec(spec)
+    sys.modules["responses"] = module
+    spec.loader.exec_module(module)
+
+    if not hasattr(module, "activate"):
+        raise ImportError("Unable to load the third-party `responses` package")
+    return module
+
+
+responses = _load_http_mocking_responses()
+
+
 @pytest.fixture
 def base_url():
     return "http://localhost:8000"
diff --git a/tests/test_litellm/proxy/management_endpoints/test_customer_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_customer_endpoints.py
index 25ff6f89427..8aeb1009101 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_customer_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_customer_endpoints.py
@@ -11,7 +11,7 @@ from litellm.proxy._types import (
     LitellmUserRoles,
     ProxyException,
 )
-from litellm.proxy.auth.user_api_key_auth import UserAPIKeyAuth
+from litellm.proxy.auth.user_api_key_auth import UserAPIKeyAuth, user_api_key_auth
 from litellm.proxy.management_endpoints.customer_endpoints import router
 
 app = FastAPI()
@@ -42,11 +42,14 @@ def mock_prisma_client():
 
 @pytest.fixture
 def mock_user_api_key_auth():
-    with patch("litellm.proxy.proxy_server.user_api_key_auth") as mock:
-        mock.return_value = UserAPIKeyAuth(
-            user_id="test-user", user_role=LitellmUserRoles.PROXY_ADMIN
-        )
-        yield mock
+    original_overrides = app.dependency_overrides.copy()
+    app.dependency_overrides[user_api_key_auth] = lambda: UserAPIKeyAuth(
+        user_id="test-user", user_role=LitellmUserRoles.PROXY_ADMIN
+    )
+    try:
+        yield
+    finally:
+        app.dependency_overrides = original_overrides
 
 
 def test_update_customer_success(mock_prisma_client, mock_user_api_key_auth):
diff --git a/tests/test_litellm/proxy/test_proxy_cli.py b/tests/test_litellm/proxy/test_proxy_cli.py
index 349fe76ed71..6c6ea11bf90 100644
--- a/tests/test_litellm/proxy/test_proxy_cli.py
+++ b/tests/test_litellm/proxy/test_proxy_cli.py
@@ -348,7 +348,10 @@ class TestProxyInitializationHelpers:
             },
         ), patch(
             "litellm.proxy.proxy_cli.ProxyInitializationHelpers._get_default_unvicorn_init_args"
-        ) as mock_get_args:
+        ) as mock_get_args, patch(
+            "litellm.proxy.proxy_cli.ProxyInitializationHelpers._is_port_in_use",
+            return_value=False,
+        ):
             mock_get_args.return_value = {
                 "app": "litellm.proxy.proxy_server:app",
                 "host": "localhost",
diff --git a/tests/test_litellm/test_main.py b/tests/test_litellm/test_main.py
index ce5873f5063..c241813d08a 100644
--- a/tests/test_litellm/test_main.py
+++ b/tests/test_litellm/test_main.py
@@ -39,6 +39,12 @@ def add_api_keys_to_env(monkeypatch):
     monkeypatch.setenv("AWS_ACCESS_KEY_ID", "my-fake-aws-access-key-id")
     monkeypatch.setenv("AWS_SECRET_ACCESS_KEY", "my-fake-aws-secret-access-key")
     monkeypatch.setenv("AWS_REGION", "us-east-1")
+    # Keep these transformation tests on the simple access-key path. A leaked
+    # session token or role/web-identity env var pushes Bedrock auth down a
+    # different branch and fails before the mocked HTTP client is exercised.
+    monkeypatch.delenv("AWS_SESSION_TOKEN", raising=False)
+    monkeypatch.delenv("AWS_ROLE_ARN", raising=False)
+    monkeypatch.delenv("AWS_WEB_IDENTITY_TOKEN_FILE", raising=False)
 
 
 @pytest.fixture