diff --git a/dev_config/python/mypy.ini b/dev_config/python/mypy.ini
index c29449969f..c41f425b5d 100644
--- a/dev_config/python/mypy.ini
+++ b/dev_config/python/mypy.ini
@@ -7,6 +7,7 @@ warn_unreachable = True
 warn_redundant_casts = True
 no_implicit_optional = True
 strict_optional = True
+disable_error_code = type-abstract
 
 # Exclude third-party runtime directory from type checking
 exclude = (third_party/|enterprise/)
diff --git a/openhands/experiments/experiment_manager.py b/openhands/experiments/experiment_manager.py
index 96a81b9652..4a5857d95b 100644
--- a/openhands/experiments/experiment_manager.py
+++ b/openhands/experiments/experiment_manager.py
@@ -31,13 +31,15 @@ def load_experiment_config(conversation_id: str) -> ExperimentConfig | None:
 class ExperimentManager:
     @staticmethod
     def run_conversation_variant_test(
-        user_id: str, conversation_id: str, conversation_settings: ConversationInitData
+        user_id: str | None,
+        conversation_id: str,
+        conversation_settings: ConversationInitData,
     ) -> ConversationInitData:
         return conversation_settings
 
     @staticmethod
     def run_config_variant_test(
-        user_id: str, conversation_id: str, config: OpenHandsConfig
+        user_id: str | None, conversation_id: str, config: OpenHandsConfig
     ) -> OpenHandsConfig:
         exp_config = load_experiment_config(conversation_id)
         if exp_config and exp_config.config:
diff --git a/openhands/server/routes/manage_conversations.py b/openhands/server/routes/manage_conversations.py
index ced25610c5..d996feecd9 100644
--- a/openhands/server/routes/manage_conversations.py
+++ b/openhands/server/routes/manage_conversations.py
@@ -45,7 +45,6 @@ from openhands.server.services.conversation_service import (
     setup_init_conversation_settings,
 )
 from openhands.server.shared import (
-    ConversationManagerImpl,
     ConversationStoreImpl,
     config,
     conversation_manager,
@@ -397,7 +396,7 @@ async def get_prompt(
     )
 
     prompt_template = generate_prompt_template(stringified_events)
-    prompt = generate_prompt(llm_config, prompt_template, conversation_id)
+    prompt = await generate_prompt(llm_config, prompt_template, conversation_id)
 
     return JSONResponse(
         {
@@ -413,7 +412,7 @@ def generate_prompt_template(events: str) -> str:
     return template.render(events=events)
 
 
-def generate_prompt(
+async def generate_prompt(
     llm_config: LLMConfig, prompt_template: str, conversation_id: str
 ) -> str:
     messages = [
@@ -427,7 +426,7 @@ def generate_prompt(
         },
     ]
 
-    raw_prompt = ConversationManagerImpl.request_llm_completion(
+    raw_prompt = await conversation_manager.request_llm_completion(
         'remember_prompt', conversation_id, llm_config, messages
     )
     prompt = re.search(r'<update_prompt>(.*?)</update_prompt>', raw_prompt, re.DOTALL)
diff --git a/openhands/utils/import_utils.py b/openhands/utils/import_utils.py
index 49b17d9d2a..905904c3ff 100644
--- a/openhands/utils/import_utils.py
+++ b/openhands/utils/import_utils.py
@@ -31,6 +31,14 @@ def import_from(qual_name: str):
 
 
 @lru_cache()
+def _get_impl(cls: type[T], impl_name: str | None) -> type[T]:
+    if impl_name is None:
+        return cls
+    impl_class = import_from(impl_name)
+    assert cls == impl_class or issubclass(impl_class, cls)
+    return impl_class
+
+
 def get_impl(cls: type[T], impl_name: str | None) -> type[T]:
     """Import and validate a named implementation of a base class.
 
@@ -62,8 +70,4 @@ def get_impl(cls: type[T], impl_name: str | None) -> type[T]:
 
     The implementation is cached to avoid repeated imports of the same class.
     """
-    if impl_name is None:
-        return cls
-    impl_class = import_from(impl_name)
-    assert cls == impl_class or issubclass(impl_class, cls)
-    return impl_class
+    return _get_impl(cls, impl_name)  # type: ignore