Specification (1.0)
Introduction

Introduction

The Open Tool Calling (OTC) standard establishes a set of protocols and formats to facilitate communication between agents (clients) and tools (functions or services) in distributed systems. It ensures that tool definitions, requests, and responses adhere to a structured and open standard.

This document defines the structures and protocols used to describe tools, initiate tool calls, and process responses. The standard consists of a set of JSON schemas that govern tool definitions, tool requests, and tool responses as described in the OTC OpenAPI spec (opens in a new tab). It aims to provide a unified, extensible, and interoperable framework for client-to-tool interactions.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 (opens in a new tab) [RFC2119 (opens in a new tab)] [RFC8174 (opens in a new tab)] when, and only when, they appear in all capitals, as shown here.

Terminology

  • Tool: A service or function that can be invoked by an agent using the defined protocols.
  • Tool Server: An entity that hosts a collection of tools and provides a trusted execution environment for executing tools (functions or services).
  • Agent: An entity that issues requests to Tool Servers to execute tools.

Design Principles

The Open Tool Calling standard is designed to be:

  • Familiar: The standard is designed to feel comfortable to developers who are familiar with REST and JSON.
  • Interoperable: The standard is intended to promote interoperability between agents and tools. It is designed to be easy to implement for different languages and frameworks.
  • Lightweight: The standard is designed to be lightweight and easy to understand.
  • Extensible: The standard is designed to be extensible. New parameters or response types can be added as additional properties in the respective schemas.

Editors

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