OAuth 2.0 Agents Native Authorization via Structured Elicitation

This document defines a Structured Elicitation extension to the OAuth 2.0 First-Party Applications (FiPA) specification [FiPA], establishing a standard metadata format for FiPA authorization challenge responses. FiPA leaves the format for advertising available authenticators and their required inputs undefined, preventing interoperable implementation by AI Agents and other non- browser clients. This extension adds an elicitations array to the FiPA Authorization Challenge Response, providing a standard metadata format for authenticator challenges. Model Context Protocol (MCP) Elicitation [MCP-Elicitation] is the normative reference binding. This specification covers the just-in-time (JIT) authorization for AI Agents executing on behalf of users in Human-to-Agent (H2A) flows.