diff --git a/index.bs b/index.bs
index 759825bf..606c4bbe 100644
--- a/index.bs
+++ b/index.bs
@@ -3058,6 +3058,11 @@ partial interface MLGraphBuilder {
     1. If |input|'s [=MLOperand/dataType=] is not {{MLOperandDataType/"float32"}} or {{MLOperandDataType/"float16"}}, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/rank=] of any of |input|, |weight| or |recurrentWeight| is not 3, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/dataType=] of either |weight| or |recurrentWeight| is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
+    1. If |hiddenSize| * 6 is not a [=valid dimension=], then [=exception/throw=] a {{TypeError}}.
+        <details class=note>
+          <summary>Why |hiddenSize| * 6 ?</summary>
+          Some underlying platforms operate on a single bias tensor which is a concatenation of {{MLGruOptions/bias}} and {{MLGruOptions/recurrentBias}}. Therefore, 3 * |hiddenSize| + 3 * |hiddenSize| must also be a [=valid dimension=].
+        </details>
     1. If |options|.{{MLGruOptions/bias}} [=map/exists=]:
         1. If its [=MLOperand/dataType=] is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
         1. If its [=MLOperand/shape=][1] is not equal to 3 * |hiddenSize|, then [=exception/throw=] a {{TypeError}}.
@@ -3238,6 +3243,11 @@ partial interface MLGraphBuilder {
     1. If |input|'s [=MLOperand/dataType=] is not {{MLOperandDataType/"float32"}} or {{MLOperandDataType/"float16"}}, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/rank=] of any of |input|, |weight|, |recurrentWeight| or |hiddenState| is not 2, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/dataType=] of any of |weight|, |recurrentWeight|, or |hiddenState| is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
+    1. If |hiddenSize| * 6 is not a [=valid dimension=], then [=exception/throw=] a {{TypeError}}.
+        <details class=note>
+          <summary>Why |hiddenSize| * 6 ?</summary>
+          Some underlying platforms operate on a single bias tensor which is a concatenation of {{MLGruCellOptions/bias}} and {{MLGruCellOptions/recurrentBias}}. Therefore, 3 * |hiddenSize| + 3 * |hiddenSize| must also be a [=valid dimension=].
+        </details>
     1. If |weight|'s [=MLOperand/shape=][0] is not equal to 3 * |hiddenSize|, then [=exception/throw=] a {{TypeError}}.
     1. If |recurrentWeight|'s [=MLOperand/shape=][0] is not equal to 3 * |hiddenSize|, then [=exception/throw=] a {{TypeError}}.
     1. If |options|.{{MLGruOptions/bias}} [=map/exists=]:
@@ -3976,6 +3986,11 @@ partial interface MLGraphBuilder {
     1. If the [=MLOperand/rank=] of any of |input|, |weight| or |recurrentWeight| is not 3, then [=exception/throw=] a {{TypeError}}.
     1. If |input|'s [=MLOperand/shape=][0] is not equal to |steps|, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/dataType=] of either |weight| or |recurrentWeight| is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
+    1. If |hiddenSize| * 8 is not a [=valid dimension=], then [=exception/throw=] a {{TypeError}}.
+        <details class=note>
+          <summary>Why |hiddenSize| * 8 ?</summary>
+          Some underlying platforms operate on a single bias tensor which is a concatenation of {{MLLstmOptions/bias}} and {{MLLstmOptions/recurrentBias}}. Therefore, 4 * |hiddenSize| + 4 * |hiddenSize| must also be a [=valid dimension=].
+        </details>
     1. Let |batchSize| be |input|'s [=MLOperand/shape=][1].
     1. If |options|.{{MLLstmOptions/bias}} [=map/exists=]:
         1. If its [=MLOperand/dataType=] is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
@@ -4193,6 +4208,11 @@ partial interface MLGraphBuilder {
     1. If |input|'s [=MLOperand/dataType=] is not {{MLOperandDataType/"float32"}} or {{MLOperandDataType/"float16"}}, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/rank=] of any of |input|, |weight|, |recurrentWeight|, |hiddenState| or |cellState| is not 2, then [=exception/throw=] a {{TypeError}}.
     1. If the [=MLOperand/dataType=] of any of |weight|, |recurrentWeight|, |hiddenState| or |cellState| is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.
+    1. If |hiddenSize| * 8 is not a [=valid dimension=], then [=exception/throw=] a {{TypeError}}.
+        <details class=note>
+          <summary>Why |hiddenSize| * 8 ?</summary>
+          Some underlying platforms operate on a single bias tensor which is a concatenation of {{MLLstmCellOptions/bias}} and {{MLLstmCellOptions/recurrentBias}}. Therefore, 4 * |hiddenSize| + 4 * |hiddenSize| must also be a [=valid dimension=].
+        </details>
     1. Let |batchSize| be |input|'s [=MLOperand/shape=][0].
     1. If |options|.{{MLLstmCellOptions/bias}} [=map/exists=]:
         1. If its [=MLOperand/dataType=] is not equal to |input|'s [=MLOperand/dataType=], then [=exception/throw=] a {{TypeError}}.