Ruby UTCP

Ruby UTCP is a Ruby implementation of version 1.1 of the Universal Tool Calling Protocol, published under the MIT licence by the protocol's own organisation. The idea UTCP argues for is that a tool-calling standard should not require every integration to be re-exposed through one intermediary: an agent reads a UTCP manual to discover what a tool is and how to reach it, stores and searches those manuals locally, and then calls the tool directly over whatever protocol it already speaks. This gem supports twelve of them — HTTP, server-sent events, streamable HTTP, a command line, WebSocket, gRPC, GraphQL, TCP, UDP, WebRTC, MCP itself and plain text — with a File transport added as a Ruby-specific extension, alongside streaming, authentication, discovery from OpenAPI descriptions and a CodeMode for multi-tool workflows. It is the newest piece of a project that has shipped before: UTCP itself in July 2025, a UTCP Agent library in August 2025 and Code Mode in November 2025. One caveat on the date: the repository carries no dated release, so 19 September is the date of the launch post rather than of a tagged version. It is free and open source, and no price is published or implied.