What is Externally Owned Account (EOA)?
An Externally Owned Account (EOA) is a blockchain account controlled by a private key held by a person or system — as opposed to a contract account which is controlled by smart contract code.
WHY IT MATTERS
Ethereum has two account types: EOAs and Contract Accounts. EOAs are controlled by whoever holds the private key. They can initiate transactions, sign messages, and hold ETH and tokens. Every human user interacts with Ethereum through an EOA.
The limitation: EOAs have no programmable logic. They can't enforce spending rules, require multi-sig, or implement recovery mechanisms natively. This is why account abstraction (ERC-4337) is significant — it brings smart contract capabilities to user accounts.
For AI agents, EOAs are the simplest wallet type but the most dangerous to give direct access to. An agent with an EOA's private key has unrestricted access to all funds.
HOW POLICYLAYER USES THIS
PolicyLayer addresses the EOA limitation for agents. Instead of giving an agent an EOA's private key (unrestricted access), PolicyLayer uses session keys and smart contract policies to give agents limited, controlled access — the programmability that raw EOAs lack.