Build Hour: Agentic Tool Calling

Quick Overview

OpenAI's Build Hour demonstrates how to leverage the Agents SDK and new APIs for agentic tool calling, enabling developers to build sophisticated, goal-oriented agents that can reason and perform complex, long-horizon tasks. The session highlights the practical implementation of these concepts through live coding, showcasing how to define agents with tools, integrate them into backend systems using Flask, and manage task execution with features like background processing and progress visualization via to-dos, ultimately empowering users to create more autonomous and capable AI applications.

Key Points: OpenAI's Build Hour focuses on agentic tool calling, demonstrating how to build agents that can reason and execute long-horizon tasks using the Agents SDK and new API features. The session features live coding to build a task system, starting with a simple agent and then adding tools like 'getuserdata' and 'refund' to handle customer service scenarios. A practical backend implementation using Flask is shown, detailing how to create SSE endpoints for streaming agent events and manage background task execution. The concept of "tasks" is introduced as a new abstraction for long-horizon goals, broken down into agent definition, infrastructure, product interaction, and evaluation. A key feature demonstrated is the use of "to-dos" within tasks, allowing agents to surface progress to users by updating a to-do list, enhancing transparency and user experience. Delegation is discussed as a pattern where one agent can initiate tasks with other agents or models, enabling non-blocking operations and continuous interaction. The session covers essential considerations for building agents, including goal specification, tool integration, infrastructure setup (runtime environments, failure handling), product interface design, and evaluation methods like LLM-based graders.

Context: This OpenAI Build Hour session, hosted by Sarah Urbonus and Alain from the developer experience team, focuses on empowering developers with best practices and tools to scale their companies using OpenAI's APIs and models. Kicking off 2025, the series aims to provide practical, hands-on guidance, with this specific episode concentrating on the flagship models, increased context capabilities, and the "codecs" tool. The session emphasizes the practical application of these concepts through live coding and demonstrations, building upon recent OpenAI releases like the Responses API, hosted tools, and the Agents SDK.