How to start building AI agents with OpenAI Agentic SDK: A practical guide

As AI systems move beyond passive prompts toward autonomous decision-making, the concept of agentic AI has emerged as a foundational shift. Agentic AI refers to systems that can reason, act autonomously, interact with tools and APIs, and complete multi-step goals. OpenAI’s new Agentic SDK provides a standardized framework for building such AI agents—bridging large language models with structured tool use, memory, and reasoning loops.

This article offers a practical, human-readable guide on how to get started with the OpenAI Agentic SDK. You’ll learn how to create your first AI agent, define tools, manage context, and handle task planning—all using a clean and production-friendly approach.

What is OpenAI's Agentic SDK?

The OpenAI Agentic SDK is a Python or Typescript framework that enables developers to create agentic AI systems using OpenAI models (e.g., GPT-4o). It simplifies the orchestration of:

  • Tool usage: Letting the model interact with external APIs, functions, and systems
  • Task planning and execution: Breaking down goals into steps
  • Memory and state: Persisting information between steps
  • Multi-turn conversations: With grounding in actions and retrieved context

Why use the Agentic SDK?

Traditional prompt-based usage of LLMs is stateless and limited to single-turn reasoning. In contrast, agentic AI systems can:

  • Take autonomous actions
  • React to API responses
  • Defer and retry sub-tasks
  • Coordinate across plugins, databases, and services
  • Maintain short-term and long-term memory

The Agentic SDK offers a flexible yet opinionated scaffold for building these types of systems safely and systematically.

Key components of the Agentic SDK

Before you start coding, it helps to understand the core building blocks:

ComponentDescription
AgentThe main controller that receives tasks and decides how to execute them
ToolsFunctions or APIs the agent can use (e.g., calculator, web search, database query)
PlannerDetermines how to break tasks into sub-steps
MemoryStores and retrieves historical context
Observer/ReporterLogs actions or emits real-time feedback to UIs

Step-by-step: building an AI agent with OpenAI Agentic SDK

Let’s walk through creating a simple AI agent that can perform calculations, look up current weather, and answer user questions based on those actions.

1. Install the OpenAI SDK

The Agentic SDK is part of OpenAI’s Python client as of mid-2024. Make sure your version is up to date:

1 bash
2 pip install --upgrade openai

2. Define your tools

Tools are functions the agent can call. You register them using decorators so that GPT knows how to use them.

1 python
2 from openai import tool

@tool
def add_numbers(a: int, b: int) -> int:
"""Adds two numbers and returns the result."""
return a + b

@tool
def get_weather(city: str) -> str:
"""Returns fake weather for demo."""
return f"The weather in {city} is 29°C and sunny."

Each tool should have:

  • A Python type signature
  • A clear, single-purpose description
  • Side-effect awareness if it touches systems like databases or email

3. Create an agent with tools

Now instantiate an agent and give it access to the tools.

1 python
2 from openai import AssistantAgent

agent = AssistantAgent(
tools=[add_numbers, get_weather],
model="gpt-4o"
)

The model you choose must support function calling (e.g., GPT-4o or GPT-4-turbo). The agent will automatically invoke tools as needed.

4. Start a conversation with your agent

You can now start sending messages to the agent. It will determine whether to respond directly or call a tool.

1 python
2 response = agent.chat("What's the weather in Miami and also add 12 and 15?")
print(response)

Under the hood:

  • The agent parses the question
  • It determines tool usage
  • Calls get_weather("Chennai")
  • Calls add_numbers(12, 15)
  • Responds with a combined answer

How the agent plans and reasons

You can extend the agent’s reasoning loop by defining a Planner. This is a strategy engine that breaks high-level tasks into steps.

For example:

1 python
2 from openai import TaskPlanner

class CustomPlanner(TaskPlanner):
def plan(self, task, tools, memory):
# Insert logic to decide task order or retry paths
return super().plan(task, tools, memory)

You can inject this planner into the agent during creation. Planners are useful when your AI agents need to coordinate multi-step workflows—such as reading emails, extracting data, making decisions, and sending replies.

Managing agent memory and state

By default, agents can maintain a short-term memory within a single session. You can extend this to longer-term or persistent memory via:

  • Embedding-based vector search (e.g., Pinecone, Weaviate)
  • Session storage (Redis, PostgreSQL, etc.)
  • File-backed scratchpad history

For instance:

1 python
2 agent.memory.save_context("user_name", "Zylker")
agent.memory.retrieve_context("user_name") # returns "Zylker"

This becomes crucial in applications like personal assistants or customer support bots where context continuity improves user experience.

Real-world use cases for Agentic SDK

Use caseHow agents help
Customer support botsCan look up ticket history, perform account actions, and suggest solutions
Workflow automationAgents can read emails, fetch data from APIs, and fill out forms
Data assistantsPull structured data from databases and generate insights on demand
AI copilotsHelp engineers or analysts write queries, generate reports, or test APIs

How to deploy agentic AI safely

Autonomous AI introduces new safety and governance concerns. When using the Agentic SDK, consider:

  • Tool validation: Restrict inputs/outputs and validate data before execution.
  • Rate limiting: Prevent abuse of tool APIs.
  • Audit logs: Track which actions the agent took and why.
  • Guardrails: Implement policies to prevent risky behavior (e.g., never delete files).

You can also use human-in-the-loop designs where agents propose actions, and humans approve them.

Comparison: Agentic SDK vs LangChain vs Semantic Kernel

FeatureOpenAI Agentic SDKLangChainSemantic Kernel
Tight OpenAI integration
Clean function interface
Native model supportGPT-4o, GPT-4-turboMulti-providerMulti-provider
Ideal forProduction OpenAI workloadsRapid prototypingEnterprise orchestration

If you are primarily working with OpenAI models and want high-fidelity tool calling, the Agentic SDK is the most seamless choice.

Final thoughts: Building reliable AI agents with the OpenAI Agentic SDK

The Agentic SDK brings structure, safety, and scalability to agent-based AI systems. It abstracts the repetitive tasks of routing, tool invocation, and state management—letting you focus on task design and user experience.

By starting with simple tools and layering on planning and memory, you can gradually evolve your agents from basic assistants to fully autonomous copilots that operate within your domain.

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