diff --git a/packages/cosmwasm/src/cosmwasmclient.ts b/packages/cosmwasm/src/cosmwasmclient.ts
index 1f356b1d..358c0fda 100644
--- a/packages/cosmwasm/src/cosmwasmclient.ts
+++ b/packages/cosmwasm/src/cosmwasmclient.ts
@@ -118,7 +118,8 @@ export interface Contract {
 }
 
 export interface ContractCodeHistoryEntry {
-  readonly operation: string;
+  /** The source of this history entry */
+  readonly operation: "Genesis" | "Init" | "Migrate";
   readonly codeId: number;
   readonly msg: object;
 }
diff --git a/packages/cosmwasm/src/lcdapi/wasm.ts b/packages/cosmwasm/src/lcdapi/wasm.ts
index 330eddfa..22edd2b2 100644
--- a/packages/cosmwasm/src/lcdapi/wasm.ts
+++ b/packages/cosmwasm/src/lcdapi/wasm.ts
@@ -54,8 +54,8 @@ export interface ContractInfo {
 
 // An entry in the contracts code/ migration history
 export interface ContractCodeHistoryEntry {
-  // operation can be "Init", "Migrate", "Genesis"
-  readonly operation: string;
+  /** The source of this history entry */
+  readonly operation: "Genesis" | "Init" | "Migrate";
   readonly code_id: number;
   readonly msg: object;
 }
diff --git a/packages/cosmwasm/types/cosmwasmclient.d.ts b/packages/cosmwasm/types/cosmwasmclient.d.ts
index 65d2ea2f..a45dd0a5 100644
--- a/packages/cosmwasm/types/cosmwasmclient.d.ts
+++ b/packages/cosmwasm/types/cosmwasmclient.d.ts
@@ -85,7 +85,8 @@ export interface Contract {
   readonly label: string;
 }
 export interface ContractCodeHistoryEntry {
-  readonly operation: string;
+  /** The source of this history entry */
+  readonly operation: "Genesis" | "Init" | "Migrate";
   readonly codeId: number;
   readonly msg: object;
 }
diff --git a/packages/cosmwasm/types/lcdapi/wasm.d.ts b/packages/cosmwasm/types/lcdapi/wasm.d.ts
index e01f0d42..621eac1b 100644
--- a/packages/cosmwasm/types/lcdapi/wasm.d.ts
+++ b/packages/cosmwasm/types/lcdapi/wasm.d.ts
@@ -34,7 +34,8 @@ export interface ContractInfo {
   readonly label: string;
 }
 export interface ContractCodeHistoryEntry {
-  readonly operation: string;
+  /** The source of this history entry */
+  readonly operation: "Genesis" | "Init" | "Migrate";
   readonly code_id: number;
   readonly msg: object;
 }