diff --git a/src/connectors/webwallet/constants.ts b/src/connectors/webwallet/constants.ts
index c0357e0..76e9a69 100644
--- a/src/connectors/webwallet/constants.ts
+++ b/src/connectors/webwallet/constants.ts
@@ -26,3 +26,5 @@ export const RPC_NODE_URL_TESTNET =
 
 export const RPC_NODE_URL_MAINNET =
   "https://cloud.argent-api.com/v1/starknet/mainnet/rpc/v0.6"
+
+export const OFFCHAIN_SESSION_ENTRYPOINT = "use_offchain_session"
diff --git a/src/connectors/webwallet/starknetWindowObject/account.ts b/src/connectors/webwallet/starknetWindowObject/account.ts
index 5a3a525..a93b217 100644
--- a/src/connectors/webwallet/starknetWindowObject/account.ts
+++ b/src/connectors/webwallet/starknetWindowObject/account.ts
@@ -16,6 +16,7 @@ import {
   SIGN_MESSAGE_POPUP_HEIGHT,
   SIGN_MESSAGE_POPUP_WIDTH,
 } from "../helpers/popupSizes"
+import { OFFCHAIN_SESSION_ENTRYPOINT } from "../constants"
 
 class UnimplementedSigner implements SignerInterface {
   async getPubKey(): Promise<string> {
@@ -64,7 +65,7 @@ export class MessageAccount extends Account implements AccountInterface {
       if (
         Array.isArray(calls) &&
         calls[0] &&
-        calls[0].entrypoint === "use_offchain_session"
+        calls[0].entrypoint === OFFCHAIN_SESSION_ENTRYPOINT
       ) {
         setPopupOptions({
           width: 1,
diff --git a/src/connectors/webwallet/starknetWindowObject/argentStarknetWindowObject.ts b/src/connectors/webwallet/starknetWindowObject/argentStarknetWindowObject.ts
index 8a3ead7..db7c1d4 100644
--- a/src/connectors/webwallet/starknetWindowObject/argentStarknetWindowObject.ts
+++ b/src/connectors/webwallet/starknetWindowObject/argentStarknetWindowObject.ts
@@ -14,6 +14,7 @@ import {
   SIGN_MESSAGE_POPUP_HEIGHT,
   SIGN_MESSAGE_POPUP_WIDTH,
 } from "../helpers/popupSizes"
+import { OFFCHAIN_SESSION_ENTRYPOINT } from "../constants"
 
 export const userEventHandlers: WalletEvents[] = []
 
@@ -77,7 +78,7 @@ export const getArgentStarknetWindowObject = (
           if (
             Array.isArray(calls) &&
             calls[0] &&
-            calls[0].entrypoint === "use_offchain_session"
+            calls[0].entrypoint === OFFCHAIN_SESSION_ENTRYPOINT
           ) {
             setPopupOptions({
               width: 1,
@@ -86,9 +87,7 @@ export const getArgentStarknetWindowObject = (
               atLeftBottom: true,
             })
           }
-          const hash = await proxyLink.addInvokeTransaction.mutate(
-            (call.params as any).calls,
-          )
+          const hash = await proxyLink.addInvokeTransaction.mutate(calls)
 
           return { transaction_hash: hash }
         }
diff --git a/src/types/window.ts b/src/types/window.ts
index 4740315..a0dcaca 100644
--- a/src/types/window.ts
+++ b/src/types/window.ts
@@ -1,3 +1,4 @@
+import { OFFCHAIN_SESSION_ENTRYPOINT } from "../connectors/webwallet/constants"
 import type { InvokeFunctionResponse, Signature } from "starknet"
 import { z } from "zod"
 
@@ -164,16 +165,33 @@ export type IframeMethods = {
   connect: () => void
 }
 
+export const OffchainSessionDetailsSchema = z.object({
+  nonce: bignumberishSchema,
+  maxFee: bignumberishSchema.optional(),
+  version: z.string(),
+})
+
 export const RpcCallSchema = z
   .object({
     contract_address: z.string(),
     entrypoint: z.string(),
     calldata: z.array(bignumberishSchema).optional(),
+    offchainSessionDetails: OffchainSessionDetailsSchema.optional(),
   })
-  .transform(({ contract_address, entrypoint, calldata }) => ({
-    contractAddress: contract_address,
-    entrypoint,
-    calldata: calldata || [],
-  }))
+  .transform(
+    ({ contract_address, entrypoint, calldata, offchainSessionDetails }) =>
+      entrypoint === OFFCHAIN_SESSION_ENTRYPOINT
+        ? {
+            contractAddress: contract_address,
+            entrypoint,
+            calldata: calldata || [],
+            offchainSessionDetails: offchainSessionDetails || undefined,
+          }
+        : {
+            contractAddress: contract_address,
+            entrypoint,
+            calldata: calldata || [],
+          },
+  )
 
 export const RpcCallsArraySchema = z.array(RpcCallSchema).nonempty()