Agents & Protocols

The Agent2Agent protocol (A2A) is an open protocol that lets AI agents built on different frameworks and by different vendors communicate …

An Agent Card is a JSON document in which an AI agent describes itself under the Agent2Agent (A2A) protocol: its name, what it can do …

An API (application programming interface) is, in MDN's wording, a set of features and rules in a software program that lets other …

MCP (Model Context Protocol) is an open standard that lets AI applications such as Claude or ChatGPT connect to external data sources …

An MCP server is a program that exposes capabilities such as functions, data and prompt templates to AI applications through the Model …

NLWeb (Natural Language Web) is an open project that gives websites a natural language interface for people and AI agents.

OpenAPI is a language-agnostic specification format for describing HTTP APIs.

Tool calling, also called function calling or tool use, is the ability of a language model to answer with a structured request to run a …

WebMCP is a proposed web standard that lets a website expose structured tools to AI agents working in the browser.

Agentic commerce describes purchases in which an AI agent acts on a person's behalf to find, compare, and buy products, up to and …

The Agentic Commerce Protocol (ACP) is an open standard for connecting buyers, their AI agents and businesses so that purchases can be …

The Agent Payments Protocol (AP2) is an open protocol from Google for payments that AI agents make on behalf of users.

An AI product feed is a file that provides a shop's product data in a defined format so that AI assistants can find, compare and display …

Instant Checkout was a ChatGPT feature that let users buy products without leaving the chat.

The Universal Commerce Protocol (UCP) is an open standard that lets AI agents discover products and complete purchases at businesses.

The accessibility tree is a representation of a page that the browser derives from the DOM and exposes to assistive technologies such as …

An agentic browser is a web browser with a built-in AI agent that plans and carries out tasks on a user's behalf, such as opening pages …

Agent readiness describes how well AI agents can discover, read and use a website.

ARIA (Accessible Rich Internet Applications, specifically WAI-ARIA) is a W3C specification for giving HTML elements extra information for …