MoltBrain GAME Plugin

GAME SDK plugin that gives any Virtuals AI agent persistent long-term memory and storage via MoltBrain x402 micropayments on Base.

What it does

This plugin lets Virtuals Protocol AI agents:

• Chat with MoltBrain AI for contextual assistance
• Search memories semantically across sessions
• Store and retrieve content-addressed data blobs
• Allocate, write, and read named memory slots
• Check storage capacity

Every paid endpoint costs $0.01 USDC on Base, settled via the x402 protocol (EIP-3009 TransferWithAuthorization).

Quick start

npm install @moltbrain/game-plugin

import { GameAgent } from "@virtuals-protocol/game";
import { MoltBrainPlugin } from "@moltbrain/game-plugin";

const moltbrain = new MoltBrainPlugin({
  privateKey: process.env.AGENT_PRIVATE_KEY!, // wallet with USDC on Base
});

const agent = new GameAgent(process.env.GAME_API_KEY!, {
  name: "My Agent",
  goal: "Remember everything across sessions",
  description: "An agent with persistent memory via MoltBrain",
  workers: [moltbrain.getWorker()],
});

await agent.init();
await agent.step({ verbose: true });

Configuration

Option	Required	Default	Description
privateKey	Yes	—	Hex private key for agent wallet (must hold USDC on Base)
serverUrl	No	https://app.moltbrain.dev/api/x402	MoltBrain API URL
rpcUrl	No	https://mainnet.base.org	Base RPC endpoint
id	No	moltbrain_worker	Worker ID
name	No	MoltBrain Memory Worker	Worker display name
description	No	(auto)	Worker description for the GAME planner

Available functions

Function	Cost	Description
moltbrain_chat	$0.01	Chat with MoltBrain AI
moltbrain_search	$0.01	Semantic memory search
moltbrain_store	$0.01	Store a JSON blob (content-addressed). Accepts optional label.
moltbrain_retrieve	$0.01	Retrieve blob by SHA-256 hash
moltbrain_allocate_slot	$0.01	Allocate a named memory slot. Accepts optional label.
moltbrain_write_slot	$0.01	Write data to a slot
moltbrain_read_slot	$0.01	Read data from a slot
moltbrain_stats	$0.01	Memory analytics
moltbrain_capacity	FREE	Node storage capacity

Vault dapp

Everything your agent stores or allocates shows up in the MoltBrain Storage dapp at app.moltbrain.dev/storage. Connect the same wallet your agent uses to browse, view, and delete stored data.

Use the optional label parameter on moltbrain_store and moltbrain_allocate_slot to tag items (e.g. "virtuals_agent", "session_config"). Labels appear as badges in the vault UI.

How x402 payments work

1. Agent makes an HTTP request to a MoltBrain endpoint
2. Server responds 402 Payment Required with USDC payment requirements
3. Plugin signs an EIP-3009 TransferWithAuthorization off-chain
4. Request retries with X-PAYMENT header containing the signed proof
5. PayAI facilitator verifies and settles the USDC transfer on Base

The agent wallet needs USDC on Base and a small amount of ETH for gas.

Run the example

cp .env.example .env
# Fill in GAME_API_KEY and AGENT_PRIVATE_KEY
npm install
npm run example

Links

• MoltBrain App
• MoltBrain GitHub
• Virtuals Protocol
• GAME SDK Docs
• x402 Protocol

License

MIT