diff --git a/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel/eligible.rs b/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel/eligible.rs
index 0266a5f06..0d9d19093 100644
--- a/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel/eligible.rs
+++ b/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel/eligible.rs
@@ -65,7 +65,10 @@ impl TransformerModel {
                 .map(|s| (s.chunk_len, s.chunk_start, s.is_last_chunk)),
             streams.len(),
             self.buffers.max_batch_tokens(),
-            &self.config.model_type,
+            // is_mla == AttentionType::Mla; read the underlying fact directly to
+            // avoid rebuilding the full ModelCapabilities struct on this
+            // per-prefill-batch hot path.
+            self.config.kv_lora_rank > 0,
             self.config.head_dim,
             self.buffers.scratch_bytes(),
             self.config.num_experts_per_tok,
@@ -139,7 +142,7 @@ pub(in crate::model) fn check_kernel_batched_eligible<I>(
     streams: I,
     n: usize,
     arena_cap: usize,
-    model_type: &str,
+    is_mla: bool,
     head_dim: usize,
     scratch_cap: usize,
     top_k: usize,
@@ -154,9 +157,12 @@ where
         return false;
     }
     // No MLA layers in stack (batched attention doesn't support MLA).
-    // Conservatively check via model_type — mistral is the only MLA
-    // model in Atlas today.
-    if model_type == "mistral" {
+    // Keyed on the MLA capability (AttentionType::Mla, i.e. kv_lora_rank>0),
+    // which is architecture-generic: it covers mistral AND deepseek_v4 (the
+    // old `model_type=="mistral"` string silently missed the latter, though
+    // deepseek_v4 was already rejected one check later by head_dim>256, so the
+    // outcome is unchanged on every model shipped today).
+    if is_mla {
         return false;
     }
     // No HDIM=512 layers (Gemma-4 long-attention).
diff --git a/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel_tests.rs b/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel_tests.rs
index 588d7bd3f..494ba45f8 100644
--- a/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel_tests.rs
+++ b/crates/spark-model/src/model/trait_impl/prefill_b/batch_kernel_tests.rs
@@ -24,7 +24,7 @@ fn rejects_under_two_streams() {
         std::iter::empty(),
         0,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -36,7 +36,7 @@ fn rejects_under_two_streams() {
         vec![s(4096, 0, false)],
         1,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -52,7 +52,7 @@ fn rejects_chunk_zero() {
         vec![s(4096, 0, false), s(4096, 0, false)],
         2,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -68,7 +68,7 @@ fn accepts_chunk_zero_when_explicitly_allowed() {
         vec![s(4096, 0, false), s(4096, 0, false)],
         2,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -84,7 +84,7 @@ fn accepts_uniform_paged_n_2() {
         vec![s(4096, 4096, false), s(4096, 4096, false)],
         2,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -100,7 +100,7 @@ fn rejects_mismatched_chunk_len() {
         vec![s(4096, 4096, false), s(2048, 4096, false)],
         2,
         16384,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -118,7 +118,7 @@ fn rejects_mismatched_chunk_start() {
         vec![s(4096, 12288, false), s(4096, 4096, false)],
         2,
         16384,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -134,7 +134,7 @@ fn rejects_mismatched_is_last() {
         vec![s(4096, 4096, false), s(4096, 4096, true)],
         2,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -151,7 +151,7 @@ fn rejects_arena_overflow() {
         vec![s(4096, 4096, false), s(4096, 4096, false)],
         2,
         4100,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -167,7 +167,7 @@ fn rejects_mla_model() {
         vec![s(4096, 4096, false), s(4096, 4096, false)],
         2,
         8192,
-        "mistral",
+        true,
         128,
         BIG_SCRATCH,
         TOP_K,
@@ -184,7 +184,7 @@ fn rejects_large_head_dim() {
         vec![s(4096, 4096, false), s(4096, 4096, false)],
         2,
         8192,
-        "gemma4",
+        false,
         512,
         BIG_SCRATCH,
         TOP_K,
@@ -200,7 +200,7 @@ fn accepts_n_4_uniform() {
         vec![s(2048, 2048, false); 4],
         4,
         8192,
-        "qwen3_next",
+        false,
         256,
         BIG_SCRATCH,
         TOP_K,
@@ -227,7 +227,7 @@ fn rejects_scratch_footprint_overflow() {
             streams.iter().copied(),
             4,
             arena,
-            "qwen3_next",
+            false,
             256,
             too_small,
             8,
@@ -242,7 +242,7 @@ fn rejects_scratch_footprint_overflow() {
             streams.iter().copied(),
             4,
             arena,
-            "qwen3_next",
+            false,
             256,
             enlarged,
             8,