Ruby UTCP

Ruby developers, UTCP and the agent

Ruby UTCP brings the Universal Tool Calling Protocol, in its 1.1 release, to Ruby, and is published under the MIT licence by the protocol's own organisation. It gives developers building agents in Ruby a way to discover tools, store and search their descriptions, and call them directly.

Discovering a tool from its manual

UTCP holds that tools should not all have to be routed back through a single middleman. An agent reads a UTCP manual to learn what a tool is and how to reach it, keeps those manuals locally where they can be searched, and then calls the tool over whatever protocol it already speaks.

Twelve transports and a Ruby extension

Twelve transports are supported: HTTP, server-sent events and streamable HTTP, along with WebSocket, gRPC, GraphQL, TCP, UDP and WebRTC, a command line, MCP itself and plain text. A File transport is added as a Ruby-specific extension. It also offers streaming, authentication, discovery of tools from OpenAPI descriptions, and a CodeMode for workflows that combine several tools. The repository documents secure-by-default protocol rules, response limits and authentication for each transport.

Place in the wider project

The gem follows earlier releases from the same project: the protocol in July 2025, an agent library that August, and Code Mode in November 2025. The gem is free and open source, and no price is published.