diff --git a/package-lock.json b/package-lock.json
index a193a2b..b01e212 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,6 +16,7 @@
         "ajv": "^8.17.1",
         "axios": "^1.13.2",
         "jwt-decode": "^4.0.0",
+        "ox": "^0.13.1",
         "socket.io-client": "^4.8.1",
         "tsup": "^8.5.0",
         "viem": "^2.28.2"
@@ -8673,9 +8674,9 @@
       }
     },
     "node_modules/ox": {
-      "version": "0.9.6",
-      "resolved": "https://registry.npmjs.org/ox/-/ox-0.9.6.tgz",
-      "integrity": "sha512-8SuCbHPvv2eZLYXrNmC0EC12rdzXQLdhnOMlHDW2wiCPLxBrOOJwX5L5E61by+UjTPOryqQiRSnjIKCI+GykKg==",
+      "version": "0.13.1",
+      "resolved": "https://registry.npmjs.org/ox/-/ox-0.13.1.tgz",
+      "integrity": "sha512-S6XU/Chz7HSSlAp7KYZigW8iwSyfS9M+GKTbyDQuZDsqC8S8GUFB2bLBLLB2SfHw8eE2MfymQazVXoLNljLycg==",
       "funding": [
         {
           "type": "github",
@@ -8690,7 +8691,7 @@
         "@noble/hashes": "^1.8.0",
         "@scure/bip32": "^1.7.0",
         "@scure/bip39": "^1.6.0",
-        "abitype": "^1.0.9",
+        "abitype": "^1.2.3",
         "eventemitter3": "5.0.1"
       },
       "peerDependencies": {
@@ -8703,9 +8704,9 @@
       }
     },
     "node_modules/ox/node_modules/abitype": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/abitype/-/abitype-1.1.1.tgz",
-      "integrity": "sha512-Loe5/6tAgsBukY95eGaPSDmQHIjRZYQq8PB1MpsNccDIK8WiV+Uw6WzaIXipvaxTEL2yEB0OpEaQv3gs8pkS9Q==",
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/abitype/-/abitype-1.2.3.tgz",
+      "integrity": "sha512-Ofer5QUnuUdTFsBRwARMoWKOH1ND5ehwYhJ3OJ/BQO+StkwQjHw0XyVh4vDttzHB7QOFhPHa/o413PJ82gU/Tg==",
       "license": "MIT",
       "funding": {
         "url": "https://github.com/sponsors/wevm"
@@ -10319,6 +10320,36 @@
         }
       }
     },
+    "node_modules/viem/node_modules/ox": {
+      "version": "0.9.6",
+      "resolved": "https://registry.npmjs.org/ox/-/ox-0.9.6.tgz",
+      "integrity": "sha512-8SuCbHPvv2eZLYXrNmC0EC12rdzXQLdhnOMlHDW2wiCPLxBrOOJwX5L5E61by+UjTPOryqQiRSnjIKCI+GykKg==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/wevm"
+        }
+      ],
+      "license": "MIT",
+      "dependencies": {
+        "@adraffy/ens-normalize": "^1.11.0",
+        "@noble/ciphers": "^1.3.0",
+        "@noble/curves": "1.9.1",
+        "@noble/hashes": "^1.8.0",
+        "@scure/bip32": "^1.7.0",
+        "@scure/bip39": "^1.6.0",
+        "abitype": "^1.0.9",
+        "eventemitter3": "5.0.1"
+      },
+      "peerDependencies": {
+        "typescript": ">=5.4.0"
+      },
+      "peerDependenciesMeta": {
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/viem/node_modules/ws": {
       "version": "8.18.3",
       "resolved": "https://registry.npmjs.org/ws/-/ws-8.18.3.tgz",
diff --git a/package.json b/package.json
index a8337d9..60762eb 100644
--- a/package.json
+++ b/package.json
@@ -35,6 +35,7 @@
     "ajv": "^8.17.1",
     "axios": "^1.13.2",
     "jwt-decode": "^4.0.0",
+    "ox": "^0.13.1",
     "socket.io-client": "^4.8.1",
     "tsup": "^8.5.0",
     "viem": "^2.28.2"
diff --git a/src/contractClients/acpContractClientV2.ts b/src/contractClients/acpContractClientV2.ts
index d3bcdd4..28c6e12 100644
--- a/src/contractClients/acpContractClientV2.ts
+++ b/src/contractClients/acpContractClientV2.ts
@@ -30,6 +30,8 @@ import {
 import { AcpX402 } from "../acpX402";
 import { base, baseSepolia } from "viem/chains";
 import MEMO_MANAGER_ABI from "../abis/memoManagerAbi";
+import { Attribution } from "ox/erc8021";
+import { appendBuilderCodeData } from "../utils";
 
 class AcpContractClientV2 extends BaseAcpContractClient {
   private RETRY_CONFIG = {
@@ -47,7 +49,8 @@ class AcpContractClientV2 extends BaseAcpContractClient {
     private memoManagerAddress: Address,
     private accountManagerAddress: Address,
     agentWalletAddress: Address,
-    config: AcpContractConfig = baseAcpConfigV2
+    config: AcpContractConfig = baseAcpConfigV2,
+    private builderCode?: string
   ) {
     super(agentWalletAddress, config);
   }
@@ -56,7 +59,8 @@ class AcpContractClientV2 extends BaseAcpContractClient {
     walletPrivateKey: Address,
     sessionEntityKeyId: number,
     agentWalletAddress: Address,
-    config: AcpContractConfig = baseAcpConfigV2
+    config: AcpContractConfig = baseAcpConfigV2,
+    builderCode?: string
   ) {
     const publicClients: Record<
       number,
@@ -106,7 +110,8 @@ class AcpContractClientV2 extends BaseAcpContractClient {
       memoManagerAddress.result as Address,
       accountManagerAddress.result as Address,
       agentWalletAddress,
-      config
+      config,
+      builderCode
     );
 
     acpContractClient.publicClients = publicClients;
@@ -221,10 +226,16 @@ class AcpContractClientV2 extends BaseAcpContractClient {
       throw new AcpError("Session key client not initialized");
     }
 
+    const dataSuffix = this.builderCode
+      ? Attribution.toDataSuffix({ codes: [this.builderCode] })
+      : undefined;
+
     const basePayload: any = {
       uo: operations.map((operation) => ({
         target: operation.contractAddress,
-        data: operation.data,
+        data: dataSuffix
+          ? appendBuilderCodeData(operation.data, dataSuffix as Hex)
+          : operation.data,
         value: operation.value,
       })),
     };
diff --git a/src/utils.ts b/src/utils.ts
index 1fe3f91..bb89e9c 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,4 +1,11 @@
-import { Address, decodeAbiParameters, encodeAbiParameters } from "viem";
+import {
+  Address,
+  concatHex,
+  decodeAbiParameters,
+  encodeAbiParameters,
+  Hex,
+  pad,
+} from "viem";
 import {
   arbitrum,
   arbitrumSepolia,
@@ -118,3 +125,15 @@ export function encodeTransferEventMetadata(
 
   return result;
 }
+
+export function appendBuilderCodeData(data: Hex, suffix: Hex): Hex {
+  const opDataByteLength = (data.length - 2) / 2;
+  const suffixByteLength = (suffix.length - 2) / 2;
+  const opDataPaddedSize = Math.ceil(opDataByteLength / 32) * 32;
+  const suffixPaddedSize = Math.ceil(suffixByteLength / 32) * 32;
+
+  const paddedData = pad(data, { size: opDataPaddedSize, dir: "right" });
+  const paddedSuffix = pad(suffix, { size: suffixPaddedSize });
+
+  return concatHex([paddedData, paddedSuffix]);
+}