papers/zoo-agent-nft/sections/02-background.tex

\section{Background}


\subsection{Non-Fungible Tokens}

\ERC{}-721 defines the standard NFT interface:

\begin{lstlisting}[language=Solidity,caption=ERC-721 Interface (Simplified)]
interface IERC721 {
    function ownerOf(uint256 tokenId)
        external view returns (address);
    function transferFrom(address from, address to,
        uint256 tokenId) external;
    function approve(address to, uint256 tokenId)
        external;
}
\end{lstlisting}

NFTs represent unique digital assets: artwork, collectibles, domain names, and virtual land. However, \ERC{}-721 assumes tokens are \emph{passive}---they do not act, hold assets, or generate value independently.

\subsection{Account Abstraction}

\ERC{}-4337 introduces account abstraction, enabling smart contracts to act as wallets:

\begin{itemize}
    \item \textbf{UserOperation}: Pseudo-transactions signed by any validation logic
    \item \textbf{Bundlers}: Aggregate operations for gas-efficient submission
    \item \textbf{Paymasters}: Sponsor gas for approved operations
\end{itemize}

Account abstraction provides the foundation for agent-controlled wallets but lacks agent-specific semantics.

\subsection{AI Agents}

Modern AI agents combine:

\begin{itemize}
    \item \textbf{Language Models}: For reasoning and planning
    \item \textbf{Tool Use}: For executing actions
    \item \textbf{Memory}: For maintaining context
    \item \textbf{Learning}: For improving from experience
\end{itemize}

Projects like AutoGPT, BabyAGI, and LangChain demonstrate agent capabilities but lack economic integration.