diff --git a/llama_stack/distribution/routers/routers.py b/llama_stack/distribution/routers/routers.py
index 2e87b2e24..c360bcfb0 100644
--- a/llama_stack/distribution/routers/routers.py
+++ b/llama_stack/distribution/routers/routers.py
@@ -101,7 +101,7 @@ class InferenceRouter(Inference):
         tool_choice: Optional[ToolChoice] = ToolChoice.auto,
         tool_prompt_format: Optional[ToolPromptFormat] = ToolPromptFormat.json,
         stream: Optional[bool] = False,
-        logprobs: Optional[LogProbConfig] = False,
+        logprobs: Optional[LogProbConfig] = None,
     ) -> AsyncGenerator:
         params = dict(
             model=model,
@@ -125,7 +125,7 @@ class InferenceRouter(Inference):
         content: InterleavedTextMedia,
         sampling_params: Optional[SamplingParams] = SamplingParams(),
         stream: Optional[bool] = False,
-        logprobs: Optional[LogProbConfig] = False,
+        logprobs: Optional[LogProbConfig] = None,
     ) -> Union[CompletionResponse, CompletionResponseStreamChunk]:
         return await self.routing_table.get_provider_impl(model).completion(
             model=model,
diff --git a/llama_stack/providers/impls/meta_reference/inference/inference.py b/llama_stack/providers/impls/meta_reference/inference/inference.py
index e50736b04..9abafb451 100644
--- a/llama_stack/providers/impls/meta_reference/inference/inference.py
+++ b/llama_stack/providers/impls/meta_reference/inference/inference.py
@@ -135,6 +135,10 @@ class MetaReferenceInferenceImpl(Inference, RoutableProvider):
                         assert (
                             len(token_result.logprobs) == 1
                         ), "Expected logprob to contain 1 result for the current token"
+                        assert (
+                            logprobs.top_k == 1
+                        ), "Only top_k=1 is supported for LogProbConfig"
+
                         logprobs.append(
                             TokenLogProbs(
                                 logprobs_by_token={