How to install and uninstall plugins on a Modular Account

ERC-6900 Modular Accounts implements Plugin manager interface IPluginManager.sol to support installing and uninstalling plugins on a Modular Account. This contract interface defines the method installPlugin() and uninstallPlugin() that clients can use to install or uninstall plugins on a Modular Account.

Account Kit provides a streamlined experience of interacting with the Modular Account AccoutLoupe interface easily by providing pluginManagerActions defined in @account-kit/smart-contracts package. When you connect your Modular Account to SmartAccountClient you can extend the client with pluginManagerActions, which exposes a set of methods available to call the account AccountLoupe with the client connected to the account.

There are two ways to install plugins. The first method is to use the pluginManagerActions's generic installPlugin method, but this method requires the PluginGenConfig configure the correct plugin dependencies and function references for the plugin.

Account Kit provides a more robust, easier way to install plugins with pluginActions. Each plugin comes with the its own pluginActions that includes already configured install method, named install<PluginName>, for installing any plugin of interest. For example, MultiOwnerPlugin has multiOwnerPluginActions that includes installMultiOwnerPlugin() method, and SessionKeyPlugin has sessionKeyPluginActions that includes installSessionKeyPlugin() method, all exported from the @account-kit/smart-contracts package.

This guide will use the SessionKeyPlugin as an example to show how you can install SessionKeyPlugin easily using the SmartAccountClient extended with sessionKeyPluginActions.

1. Installing the Session Key Plugin

You should first extend the SmartAccountClient connected to a Modular Account with sessionKeyPluginActions.

Then, you can use the installSessionKeyPlugin() method exposed on sessionKeyPluginActions extended smart account client to install the session key plugin for the connected account.

example.ts

import { modularAccountClient } from "./client";
import { sessionKeyPluginActions } from "@account-kit/smart-contracts";
 

// extend smart account client with sessionKeyPluginActions to call SessionKeyPlugin methods
const sessionKeyExtendedClient = modularAccountClient.extend(
  sessionKeyPluginActions
);
 
const { hash } = await sessionKeyExtendedClient.installSessionKeyPlugin({
  // 1st arg is the initial set of session keys
  // 2nd arg is the tags for the session keys
  // 3rd arg is the initial set of permissions
  args: [[], [], []],
});
 
await client.waitForUserOperationTransaction({ hash });

Refer to the Session Key section to learn more about using the SessionKeyPlugin.

2. Uninstalling the Session Key Plugin

On the other hand, uninstalling plugins usually does not involve configuring contract dependencies or function references. You can use the pluginManagerActions's generic uninstallPlugin method to uninstall a particular plugin of interest. First, extend the SmartAccountClient connected to a Modular Account with pluginManagerActions.

Then, you can use the uninstallPlugin() method exposed on pluginManagerActions extended smart account client to uninstall the session key plugin for the connected account.

example.ts

import { chain, modularAccountClient } from "./client";
import { SessionKeyPlugin } from "@account-kit/smart-contracts";
 
const { hash } = await modularAccountClient.uninstallPlugin({
  pluginAddress: SessionKeyPlugin.meta.addresses[chain.id],
});
 
await modularAccountClient.waitForUserOperationTransaction({ hash });

Extend Modular Account with Multisig

As mentioned above, you should not uninstall the multiowner plugin from a Modular Account in a single action. This will leave your account without a validator, no owner, and therefore will be unusable.

Recommended flow today: Rather than switch ownership post creation, use createModularAccountAlchemyClient OR the createMultisigAccountAlchemyClient on account creation directly depending on if you want multi-owner or multi-sig ownership respectively.

Problem: In order to switch from multi-owner (installed in Modular Account by default) to multi-sig, you will need to batch call an uninstall of the multi-owner plugin and an install of the multi-sig plugin. It is required to batch these steps! If you uninstall the multi-owner plugin in a single action, the account will no longer have a validation function, and will be bricked (unusable).

Solution for extending Modular Account AFTER deployment: You will need to manually encode 1) the uninstall of the multi-owner plugin and 2) the install of the multi-sig plugin and batch those together in one UO (using encodeFunctionData and batching using sendUserOperation). We are working to make this workflow easier in the next SDK version.

See a working example in this discussion.

After uninstalling and installing successfully, you will then be able to use the Multisig Account Client to sign and send UOs.