diff --git a/crates/ml/src/cuda_pipeline/common_device_functions.cuh b/crates/ml/src/cuda_pipeline/common_device_functions.cuh
index 42e99435c..f9d172007 100644
--- a/crates/ml/src/cuda_pipeline/common_device_functions.cuh
+++ b/crates/ml/src/cuda_pipeline/common_device_functions.cuh
@@ -1632,6 +1632,9 @@ __device__ __forceinline__ int simulate_fill_check(
     } while (0)
 #endif
 
+/* Guard: only compile when DQN architecture constants are defined */
+#if defined(SHARED_H1) && defined(SHARED_H2) && defined(VALUE_H) && defined(ADV_H)
+
 /**
  * Warp-cooperative dueling Q-network forward pass (clean, no noise).
  *
@@ -1711,3 +1714,5 @@ __device__ void q_forward_dueling_warp_shmem(
         q_values[i] = value + adv[i] - adv_mean;
     }
 }
+
+#endif /* SHARED_H1 && SHARED_H2 && VALUE_H && ADV_H */