Merge pull request #38914 from BerriAI/litellm_fix_skills_hook_import_side_effect

fix(proxy): register SkillsInjectionHook at proxy startup instead of import time

litellm/proxy/hooks/litellm_skills/__init__.py

@@ -21,10 +21,7 @@ from litellm.llms.litellm_proxy.skills import (
     code_execution_handler,
     get_litellm_code_execution_tool,
 )
-from litellm.proxy.hooks.litellm_skills.main import (
-    SkillsInjectionHook,
-    skills_injection_hook,
-)
+from litellm.proxy.hooks.litellm_skills.main import SkillsInjectionHook
 
 __all__ = [
     "LITELLM_CODE_EXECUTION_TOOL",
@@ -35,5 +32,4 @@ __all__ = [
     "SkillsSandboxExecutor",
     "code_execution_handler",
     "get_litellm_code_execution_tool",
-    "skills_injection_hook",
 ]

litellm/proxy/hooks/litellm_skills/main.py

@@ -29,6 +29,7 @@ import json
 from collections.abc import Mapping, Sequence
 from typing import TYPE_CHECKING, Any, Final, Protocol
 
+import litellm
 from litellm._logging import verbose_proxy_logger
 from litellm.caching.caching import DualCache
 from litellm.integrations.custom_logger import CustomLogger
@@ -493,7 +494,6 @@ class SkillsInjectionHook(CustomLogger):
 
         Returns the final response with generated files inline.
         """
-        import litellm
         from litellm.llms.litellm_proxy.skills.code_execution import (
             LiteLLMInternalTools,
         )
@@ -723,7 +723,6 @@ print('No executable skill module found')
 
         Returns the final response with generated files inline.
         """
-        import litellm
         from litellm.llms.litellm_proxy.skills.code_execution import (
             LiteLLMInternalTools,
         )
@@ -913,11 +912,3 @@ print('No executable skill module found')
         verbose_proxy_logger.debug("SkillsInjectionHook: Attached %s files to response", len(generated_files))
 
         return response
-
-
-# Global instance for registration
-skills_injection_hook: Final = SkillsInjectionHook()
-
-import litellm
-
-litellm.logging_callback_manager.add_litellm_callback(skills_injection_hook)

tests/test_litellm/proxy/hooks/litellm_skills/test_main.py

@@ -1,3 +1,7 @@
+import os
+import subprocess
+import sys
+from typing import Final
 from unittest.mock import AsyncMock, patch
 
 import pytest
@@ -65,3 +69,19 @@ async def test_execute_code_loop_dispatches_litellm_skill_tool():
     mock_exec.assert_awaited_once()
     assert mock_exec.await_args.args[0] == SKILL_TOOL_NAME
     assert result is final_response
+
+
+def test_importing_proxy_hooks_does_not_mutate_litellm_callbacks():
+    script: Final = (
+        "import litellm; "
+        "litellm.callbacks = []; "
+        "import litellm.proxy.hooks; "
+        "assert len(litellm.callbacks) == 0, f'mutated: {litellm.callbacks}'"
+    )
+    result: Final = subprocess.run(
+        [sys.executable, "-c", script],
+        capture_output=True,
+        text=True,
+        env={**os.environ, "LITELLM_LOCAL_MODEL_COST_MAP": "True"},
+    )
+    assert result.returncode == 0, f"stdout: {result.stdout}\nstderr: {result.stderr}"