diff --git a/packages/sdk38/src/types.ts b/packages/sdk38/src/types.ts
index 49346bf7..e0c085a8 100644
--- a/packages/sdk38/src/types.ts
+++ b/packages/sdk38/src/types.ts
@@ -1,11 +1,15 @@
 import { Coin } from "./coins";
 import { Msg } from "./msgs";
 
-/** An Amino/Cosmos SDK StdTx */
+/**
+ * A Cosmos SDK StdTx
+ *
+ * @see https://docs.cosmos.network/master/modules/auth/03_types.html#stdtx
+ */
 export interface StdTx {
-  readonly msg: ReadonlyArray<Msg>;
+  readonly msg: readonly Msg[];
   readonly fee: StdFee;
-  readonly signatures: ReadonlyArray<StdSignature>;
+  readonly signatures: readonly StdSignature[];
   readonly memo: string | undefined;
 }
 
diff --git a/packages/sdk38/types/types.d.ts b/packages/sdk38/types/types.d.ts
index 2eb30fc9..2f3d218d 100644
--- a/packages/sdk38/types/types.d.ts
+++ b/packages/sdk38/types/types.d.ts
@@ -1,10 +1,14 @@
 import { Coin } from "./coins";
 import { Msg } from "./msgs";
-/** An Amino/Cosmos SDK StdTx */
+/**
+ * A Cosmos SDK StdTx
+ *
+ * @see https://docs.cosmos.network/master/modules/auth/03_types.html#stdtx
+ */
 export interface StdTx {
-  readonly msg: ReadonlyArray<Msg>;
+  readonly msg: readonly Msg[];
   readonly fee: StdFee;
-  readonly signatures: ReadonlyArray<StdSignature>;
+  readonly signatures: readonly StdSignature[];
   readonly memo: string | undefined;
 }
 export declare function isStdTx(txValue: unknown): txValue is StdTx;