System Overview
Brain is implemented as a layered protocol that separates capital custody, identity, authorization, execution, and payments into distinct but coordinated components. This separation enables independent validation of each function while preserving composability and interoperability with existing infrastructure.
Design Principles
Separation of concerns — each layer validates independently, enabling modular auditing
Standards-based — built on ERC-4337, EIP-7702, ERC-8004, ERC-8183, and x402
Non-custodial — the backend never holds funds or private keys
Deterministic execution — no action bypasses identity verification, policy enforcement, or payment validation
High-Level System Flow
User creates an account
User deploys one or more agents
User funds agents
Policies and budgets are attached to agents
Agents propose actions
Policy engine evaluates and signs approvals
If needed, payment intents are created and settled
Execution is routed to on-chain or off-chain systems
Results and receipts are recorded
Trust and reputation are updated on-chain
The Seven Layers
Account Abstraction
ERC-4337
Programmable smart accounts, UserOperation validation
Delegated Execution
EIP-7702
EOAs adopt Brain logic without address migration
Identity & Auth
SIWX
Cryptographic sign-in for users and agents
Trust & Reputation
ERC-8004
Persistent agent identifiers and on-chain reputation
Authorization & Policy
Brain Policy Engine
Structured constraints evaluated before every action
Execution & Commerce
ERC-8183
Conditional jobs, escrow, and external integrations
Payments
x402
HTTP-native machine payments with on-chain settlement
Standards Composition
Brain does not redefine these standards — it implements and composes them into a cohesive protocol:
ERC-4337 → programmable accounts and UserOperation-based execution
EIP-7702 → delegated execution for EOAs
ERC-8004 → agent identity and trust registry
ERC-8183 → conditional commerce and job-based settlement
ERC-7902 → wallet capability discovery
ERC-7769 → bundler and transaction infrastructure interfaces
x402 → machine-native HTTP payments