diff --git a/crates/ml/src/mamba/mod.rs b/crates/ml/src/mamba/mod.rs
index 9f53b1030..c4ddee06e 100644
--- a/crates/ml/src/mamba/mod.rs
+++ b/crates/ml/src/mamba/mod.rs
@@ -602,7 +602,16 @@ impl Mamba2SSM {
                     reason: e.to_string(),
                 })
             },
-            DType::F8E4M3 | DType::U8 | DType::U32 | DType::I64 | DType::BF16 | DType::F16 => {
+            DType::BF16 | DType::F16 => {
+                // Create as F32 scalar, then cast to the target half-precision dtype.
+                Tensor::new(&[value as f32], device)
+                    .and_then(|t| t.to_dtype(dtype))
+                    .map_err(|e| MLError::TensorCreationError {
+                        operation: format!("scalar_tensor ({:?} via F32)", dtype),
+                        reason: e.to_string(),
+                    })
+            },
+            DType::F8E4M3 | DType::U8 | DType::U32 | DType::I64 => {
                 Err(MLError::ModelError(format!(
                     "Unsupported dtype: {:?}",
                     dtype