Chapter 34: OpenAI Agents SDK
Chapter 33 gave you the conceptual foundation—agent taxonomy, architecture, and patterns. Now you'll build your first production agent using OpenAI's official Agents SDK, the framework powering ChatGPT's agentic capabilities.
OpenAI released the Agents SDK in March 2025 as a lightweight, production-ready framework for building agentic applications. Unlike wrapper libraries, it's the same infrastructure OpenAI uses internally. The SDK embodies the architecture you learned: agents with instructions, tools they can call, and handoffs between specialized agents. You'll recognize every pattern from Chapter 33 as you implement them.
This chapter follows specification-driven development throughout. You'll write specs first, then implement with Claude Code as your pair programmer. By the end, you'll have built a multi-agent system that demonstrates the patterns enterprises use in production.
Your Path to Shipping Digital FTEs
This chapter is the BUILD phase of creating Digital Full-Time Equivalents (Digital FTEs)—AI agents that work like employees, priced and sold as workforce replacements.
| Phase | Chapter | What You Learn | Outcome |
|---|---|---|---|
| BUILD | Ch34: OpenAI Agents SDK | Production agent architecture, multi-agent systems, guardrails, sessions, tracing | Working agent system |
| DISTRIBUTE | Ch42: OpenAI Apps SDK | Package agents for ChatGPT marketplace | Reach 800M+ users |
| DEPLOY | Part 7: Cloud-Native | Kubernetes, scaling, monitoring | Production infrastructure |
By chapter's end, you'll have built a Customer Support Digital FTE that:
- Routes inquiries to specialist agents (FAQ, Booking, Escalation)
- Maintains conversation context across handoffs
- Validates inputs with guardrails (abuse detection, PII filtering)
- Persists conversations with SQLite sessions
- Provides full observability through tracing
- Integrates external knowledge via MCP and RAG
The capstone includes monetization models (subscription, success fee, hybrid) so you understand how to price your Digital FTE when you're ready to ship.
What You'll Learn
By the end of this chapter, you'll be able to:
- Configure the OpenAI Agents SDK: Set up your development environment, manage API keys securely, and understand the SDK's core primitives (Agent, Runner, tools, handoffs)
- Build single agents with tools: Create agents that use function tools to interact with external systems, implementing the Tool-Use pattern from Chapter 33
- Implement multi-agent handoffs: Design systems where specialized agents hand off to each other, applying the Coordinator and Sequential patterns
- Add guardrails and safety: Implement input/output validation, content filtering, and the Human-in-the-Loop pattern for sensitive operations
- Handle streaming and async: Build responsive agents that stream responses and handle concurrent operations efficiently
- Trace and debug agents: Use OpenAI's tracing infrastructure to understand agent behavior and diagnose issues
Prerequisites
- Chapter 33: Introduction to AI Agents (conceptual foundation)
- Part 5: Python Fundamentals (async/await, type hints, dataclasses)
- Part 4: SDD-RI Fundamentals (specification-driven workflow)
- OpenAI API key with Agents SDK access