Portia

Agent Builder is part of OpenAI’s tooling for constructing agentic applications, systems that use large language models to perform multi-step tasks autonomously, with governance, tool integration, memory, orchestration, and observability baked in. The platform offers a composable set of primitives—models, tools, memory/state, guardrails, and workflow orchestration- that developers assemble into agents capable of deciding when to call a tool, when to act, and when to halt and hand off control. OpenAI provides a new Responses API that combines chat capabilities with built-in tool use, along with an Agents SDK (Python, JS/TS) that abstracts the control loop, supports guardrail enforcement (validations on inputs/outputs), handoffs between agents, session management, and tracing of agent executions. Agents can be augmented with built-in tools like web search, file search, or computer use, or custom function-calling tools.

AgentHub is a staging environment to simulate, trace, and evaluate AI agents in a private, sandboxed space that lets you ship with confidence, speed, and precision. With easy setup, you can onboard agents in minutes; a robust evaluation infrastructure provides multi-step trace logging, LLM graders, and fully customizable evaluations. Realistic user simulation employs configurable personas to model diverse behaviors and stress scenarios, and dataset enhancement synthetically expands test sets for comprehensive coverage. Prompt experimentation enables dynamic multi-prompt testing at scale, while side-by-side trace analysis lets you compare decisions, tool invocations, and outcomes across runs. A built-in AI Copilot analyzes traces, interprets results, and answers questions grounded in your own code and data, turning agent runs into clear, actionable insights. Combined human-in-the-loop and automated feedback options, along with white-glove onboarding and best-practice guidance.