LLMS-API.txt: Rise of AI agents and the need for seamless API interaction

Abstract

In the era of AI agents, inconsistent API documentation and heavyweight protocols slow down reliable interactions. LLMS-API.txt is a lightweight, text-based protocol inspired by robots.txt that lets web apps publish structured, machine-readable API definitions at a standard URL. It outlines endpoints, parameters, authentication, and rate limits so language models can execute complex calls with minimal developer overhead. Unlike Model Context Protocol (MCP), LLMS-API.txt requires only a static file, democratizing agent access while reducing hosting cost. We evaluate the format with small and state-of-the-art models across authenticated calls, rate limiting, and malformed files, demonstrating robust, efficient API interactions and a path to safer agent-driven web app integrations.