# Glossary

**Tool:** These are external services that AI agents call or interact with to perform specific actions or to increase their capabilities.

**Fiat on-ramps:** These are services that allow anyone to receive cryptocurrency in exchange for traditional currency.

**Fiat off-ramps:** These are services that allow anyone to receive traditional currency in exchange for cryptocurrency.

**Model Context Protocol (MCP):** An open protocol that facilitates interaction with AI models with external services.

**Sub-second finality:** The ability of a blockchain to facilitate, finalize, and make irreversible any transactions typically under a second.

**Executable NFT (xNFT):** An xNFT on Skynet is an NFT that is ownable, can be deployed, can hold an AI agent, can be monetized, and is modular.

**Chain abstraction:** It is a design principle or philosophy that enhances a user experience by unifying transactions or actions for different blockchains in one interface.

**Chain Agnostic:** A design approach allows any protocol to work with different blockchains without being tied to one.