diff --git a/autogpt_platform/backend/backend/blocks/llm.py b/autogpt_platform/backend/backend/blocks/llm.py
index bf197f6aad..a3b2159216 100644
--- a/autogpt_platform/backend/backend/blocks/llm.py
+++ b/autogpt_platform/backend/backend/blocks/llm.py
@@ -291,10 +291,8 @@ async def resolve_model_for_call(llm_model: LlmModel) -> ResolvedModel:
         fallback = get_fallback_model_for_disabled(llm_model.value)
         if fallback:
             logger.warning(
-                "Model '%s' is disabled. Using fallback '%s' from same provider (%s).",
-                llm_model.value,
-                fallback.slug,
-                fallback.metadata.provider,
+                f"Model '{llm_model.value}' is disabled. Using fallback "
+                f"'{fallback.slug}' from same provider ({fallback.metadata.provider})."
             )
             return ResolvedModel(
                 slug=fallback.slug,
@@ -319,7 +317,7 @@ async def resolve_model_for_call(llm_model: LlmModel) -> ResolvedModel:
         )
 
     # Case 3: Model not in registry - try refresh if DB available
-    logger.warning("Model '%s' not found in registry cache", llm_model.value)
+    logger.warning(f"Model '{llm_model.value}' not found in registry cache")
 
     from backend.data.db import is_connected
 
@@ -331,7 +329,7 @@ async def resolve_model_for_call(llm_model: LlmModel) -> ResolvedModel:
 
     # Try refreshing the registry
     try:
-        logger.info("Refreshing LLM registry for model '%s'", llm_model.value)
+        logger.info(f"Refreshing LLM registry for model '{llm_model.value}'")
         await llm_registry.refresh_llm_registry()
     except Exception as e:
         raise ModelUnavailableError(
@@ -352,7 +350,7 @@ async def resolve_model_for_call(llm_model: LlmModel) -> ResolvedModel:
             f"Enable it via the admin UI at /admin/llms."
         )
 
-    logger.info("Model '%s' loaded after registry refresh", llm_model.value)
+    logger.info(f"Model '{llm_model.value}' loaded after registry refresh")
     return ResolvedModel(
         slug=llm_model.value,
         provider=model_info.metadata.provider,
@@ -449,7 +447,7 @@ def extract_openai_tool_calls(response) -> list[ToolContentBlock] | None:
 
 def get_parallel_tool_calls_param(
     llm_model: LlmModel, parallel_tool_calls: bool | None
-) -> bool | openai.NotGiven:
+) -> bool | openai.Omit:
     """Get the appropriate parallel_tool_calls parameter for OpenAI-compatible APIs."""
     # Check for o-series models (o1, o1-mini, o3-mini, etc.) which don't support
     # parallel tool calls. Handle both bare slugs ("o1-mini") and provider-prefixed
@@ -457,7 +455,7 @@ def get_parallel_tool_calls_param(
     # start of the string or after a "/" separator.
     is_o_series = re.search(r"(^|/)o\d", llm_model) is not None
     if is_o_series or parallel_tool_calls is None:
-        return openai.NOT_GIVEN
+        return openai.omit
     return parallel_tool_calls
 
 
diff --git a/autogpt_platform/backend/backend/data/block_cost_config.py b/autogpt_platform/backend/backend/data/block_cost_config.py
index 76f02ffa0a..4e16ba767c 100644
--- a/autogpt_platform/backend/backend/data/block_cost_config.py
+++ b/autogpt_platform/backend/backend/data/block_cost_config.py
@@ -85,7 +85,9 @@ async def _build_llm_costs_from_registry() -> list[BlockCost]:
     When a model has been migrated with a custom price, that price is used instead
     of the target model's default cost.
     """
-    # Query active migrations with custom pricing overrides
+    # Query active migrations with custom pricing overrides.
+    # Note: LlmModelMigration is system-level data (no userId field) and this function
+    # is only called during app startup and admin operations, so no user ID filter needed.
     migration_overrides: dict[str, int] = {}
     try:
         active_migrations = await prisma.models.LlmModelMigration.prisma().find_many(
diff --git a/autogpt_platform/backend/backend/server/v2/llm/db.py b/autogpt_platform/backend/backend/server/v2/llm/db.py
index 136b4e694b..4ef1af4b45 100644
--- a/autogpt_platform/backend/backend/server/v2/llm/db.py
+++ b/autogpt_platform/backend/backend/server/v2/llm/db.py
@@ -204,6 +204,12 @@ async def list_models(
         page: Page number (1-indexed)
         page_size: Number of models per page
     """
+    # Validate pagination inputs to avoid runtime errors
+    if page_size < 1:
+        page_size = 50
+    if page < 1:
+        page = 1
+
     where: Any = {}
     if provider_id:
         where["providerId"] = provider_id