Agentic Reasoning Protocol (ARP) Version 2.0

This document defines the Agentic Reasoning Protocol (ARP) version 2.0, a machine-readable protocol enabling entities (brands, organizations, persons) to publish self-attested context, verified factual corrections, domain expertise, and recommendation boundaries directly to autonomous AI agents, RAG (Retrieval-Augmented Generation) pipelines, and agentic AI systems. ARP v2.0 extends the static file model of v1.x with a live REST API, bidirectional feedback channels, multi-party cryptographic attestation, W3C Decentralized Identifier (DID) anchoring, Agent-to- Agent (A2A) trust handshakes, event-driven freshness via Server-Sent Events, and first-class internationalization support. ARP complements existing web conventions (robots.txt [RFC9309], schema.org, llms.txt) but is specifically designed for the reasoning behavior of modern AI agents -- systems that do not merely index content but synthesize, infer, and make decisions on behalf of users. All examples in this document use example.com and "Example Organization" per [RFC2606] and are purely illustrative.