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The specification for the Universal Tool Calling Protocol

Universal Tool Calling Protocol (UTCP) Specification

This repository contains the official specification documentation for the Universal Tool Calling Protocol (UTCP). UTCP is a modern, flexible, and scalable standard for defining and interacting with tools across various communication protocols.

What is UTCP?

UTCP provides a standardized way for AI systems and other clients to discover and call tools from different providers, regardless of the underlying protocol used (HTTP, WebSocket, CLI, etc.). This specification defines:

  • Tool discovery mechanisms
  • Tool call formats and templates
  • Plugin-based architecture for extensibility
  • Enhanced authentication methods
  • Comprehensive error handling
  • Response processing and validation

Version 1.0 Features

UTCP v1.0 introduces significant architectural improvements:

  • Plugin Architecture: Core functionality split into pluggable components for better modularity
  • Enhanced Data Models: Improved Pydantic models with comprehensive validation
  • Multiple Protocol Support: HTTP, CLI, WebSocket, Text, and MCP protocols via plugins
  • Advanced Authentication: Expanded authentication options including API key, OAuth, and custom auth
  • Better Error Handling: Specific exception types for different error scenarios
  • Performance Optimizations: Optimized client and protocol implementations
  • Async/Await Support: Full asynchronous client interface for better performance

Contributing to the Specification

We welcome contributions to the UTCP specification! Here's how you can contribute:

  1. Fork the repository: Create your own fork of the specification repository
  2. Make your changes: Update or add documentation as needed
  3. Submit a pull request: Open a PR with your changes for review
  4. Participate in discussions: Join the conversation about proposed changes

When contributing, please follow these guidelines:

  • Ensure your changes align with the overall vision and goals of UTCP
  • Follow the established documentation structure and formatting
  • Include examples when adding new features or concepts
  • Update relevant sections to maintain consistency across the documentation

Installation and Usage

Core Package Installation

# Install the core UTCP package
pip install utcp

# Install protocol plugins as needed
pip install utcp-http utcp-cli utcp-websocket utcp-text utcp-mcp

Migration from v0.1 to v1.0

If you're upgrading from UTCP v0.1, please see our comprehensive Migration Guide which covers:

  • Breaking changes and architectural improvements
  • Step-by-step migration instructions
  • Configuration and manual format updates
  • Common migration issues and solutions

Building the Documentation Locally

Prerequisites

To build and preview the documentation site locally, you'll need:

  • Node.js version 18.0 or higher
  • npm or yarn package manager

Setup

  1. Clone the repository:

    git clone https://github.com/universal-tool-calling-protocol/utcp-specification.git
    cd utcp-specification
    
  2. Install dependencies:

    npm install
    

Running the Documentation Site

To build and serve the site locally:

npm start

This will start a local development server at http://localhost:3000 where you can preview the documentation.

Documentation Structure

The UTCP documentation is organized as follows:

  • docs/
    • index.md: Homepage and introduction to UTCP
    • introduction.md: Detailed introduction and core concepts
    • for-tool-providers.md: Guide for implementing tool providers
    • for-tool-callers.md: Guide for implementing tool callers
    • migration-v0.1-to-v1.0.md: Comprehensive migration guide from v0.1 to v1.0
    • protocols/: Documentation for each protocol type
      • http.md: HTTP protocol implementation
      • websocket.md: WebSocket protocol implementation
      • cli.md: CLI protocol implementation
      • sse.md: Server-Sent Events protocol implementation
      • text.md: Text protocol implementation
      • mcp.md: Model Context Protocol implementation
    • api/: API reference documentation
      • core/: Core API documentation
      • plugins/: Plugin API documentation
    • implementation.md: Implementation guidelines and best practices
  • versioned_docs/: Version-specific documentation for backwards compatibility

Working with the Specification

Modifying the Documentation

The documentation is built with Docusaurus and written in Markdown format. When making changes:

  1. Ensure your Markdown follows the established style
  2. Preview changes locally before submitting PRs
  3. Keep examples up-to-date with the latest specification (v1.0)
  4. Update navigation items in sidebars.ts if adding new pages
  5. Consider version compatibility when making breaking changes

File Organization

When adding new documentation:

  • Place protocol-specific documentation in docs/protocols/
  • Place API documentation in docs/api/core/ or docs/api/plugins/
  • Use consistent front matter with appropriate navigation ordering
  • Include tags for improved searchability
  • Consider versioning for breaking changes using versioned_docs/

Version Control

The UTCP specification follows semantic versioning:

  • Major versions (1.0, 2.0): Breaking changes to the protocol
  • Minor versions (1.1, 1.2): New features added in a backward-compatible manner
  • Patch versions (1.0.1, 1.0.2): Backward-compatible bug fixes and clarifications

License

This specification is distributed under the Mozilla Public License 2.0 (MPL-2.0).

Additional Resources