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# GPT Agents vs OpenAI AgentKit: What to Build With

Custom GPTs, Workspace Agents, AgentKit, the Agents SDK or n8n? What each OpenAI agent option does in late 2026 and which fits a small business build.

Micromarketing October 26, 2026

![Title card reading GPT Agents vs OpenAI AgentKit: What to Build With beside a glowing cyan node network on a dark grid](https://www.micromarketing.dev/images/optimized/resources-gpt-agents-vs-openai-agentkit-gpt-agents-vs-agentkit-hero-480.webp)

**If you want a “GPT agent” for your business in late 2026, the short answer is: use ChatGPT’s Workspace Agents for internal, prompt-built helpers on a Business or Enterprise plan, and use OpenAI’s Agents SDK (Python or TypeScript) when the agent has to live inside your own app, website or workflows.** Custom GPTs are being retired, and AgentKit’s visual Agent Builder is being wound down, so don’t start new projects on either. For many small businesses, an n8n workflow with an AI agent step is a third option that’s easier to maintain. Here’s what each one is and when it fits.

*Last verified: October 18, 2026. OpenAI renames and retires products often; check the linked official pages before you commit.*

## The quick comparison

![Comparison of OpenAI agent options for small business in late 2026: custom GPTs, Workspace Agents, AgentKit Agent Builder, Agents SDK and n8n AI agents, by status, who builds and best fit](https://www.micromarketing.dev/images/resources/gpt-agents-vs-openai-agentkit/openai-agent-options-compared.webp)

| Option | What it is | Status (Oct 2026) | Best fit |
| --- | --- | --- | --- |
| **Custom GPTs** | Custom versions of ChatGPT with instructions, files and actions | Being retired; no new GPTs on personal plans | Existing GPTs only; plan a migration |
| **Workspace Agents** | Shared, cloud-run agents inside ChatGPT for teams | Available on Business, Enterprise, Edu and Teachers plans | Internal team workflows, built by prompting |
| **AgentKit: Agent Builder** | Visual canvas for multi-agent workflows | Winding down; OpenAI says unavailable from Nov 30, 2026 | Don’t start new builds |
| **AgentKit: ChatKit** | Toolkit to embed chat-based agents in your product | Not part of the announced wind-down | Embedding an agent chat UI |
| **Agents SDK** (Python, TypeScript) | Code library for agents, tools, handoffs, guardrails and tracing | OpenAI’s recommended path for workflows in code | Agents inside your app or backend |
| **n8n AI agents** | AI Agent node inside n8n workflows | Third-party (n8n) | Agents that sit in a larger automation |

## Custom GPTs: what changed

“GPT agents” used to mean custom GPTs: a version of ChatGPT with your instructions, uploaded files and optional actions that call outside APIs. They were the easiest way to give a team a specialized assistant.

That’s changing. According to [OpenAI’s help article on GPTs](https://help.openai.com/en/articles/8554397-creating-and-editing-gpts):

- OpenAI is planning to **retire custom GPTs** and recommends moving workflows to **Plugins**, with a migration flow.
- For affected **Enterprise workspaces, retirement is planned for December 11, 2026**, and other plans are expected to follow the same timeline.
- **New GPT creation and publishing aren’t available on personal accounts** (Free, Go, Plus and Pro). Business, Enterprise and Edu workspaces can still create them where settings allow.

**What to do:** if your business relies on a custom GPT, list what it does (instructions, files, actions) now, so you can rebuild it as a Workspace Agent, a plugin or a code-based agent.

## Workspace Agents: the ChatGPT-native option

OpenAI describes Workspace Agents as an evolution of GPTs. They’re shared agents inside ChatGPT that run in the cloud, use connected apps, can run on a schedule or in Slack, and can be set to ask for approval before sensitive steps like sending an email. They’re available on ChatGPT Business, Enterprise, Edu and Teachers plans, and OpenAI moved them to credit-based pricing in May 2026.

**Good for:** internal jobs like weekly reports, lead research briefs, drafting follow-ups and answering staff questions from docs, built by describing the workflow instead of coding it.

**Not for:** customer-facing chat on your website, or agents that need to run inside your own systems with your own data store and approval logic.

## AgentKit: what’s staying and what’s going

OpenAI launched AgentKit in October 2025 as a set of building blocks: **Agent Builder** (a visual canvas for multi-agent workflows), a **Connector Registry**, **ChatKit** (embeddable chat UI) and expanded **Evals**.

On June 3, 2026, OpenAI added an update to the [AgentKit announcement](https://openai.com/index/introducing-agentkit/): it’s **winding down Agent Builder and Evals**, which won’t be available on the OpenAI platform from **November 30, 2026**. For workflows that should continue as code, OpenAI recommends the **Agents SDK**. For use cases better suited to natural-language prompting, it recommends **Workspace Agents in ChatGPT**.

So if you searched “AgentKit OpenAI” planning to build in Agent Builder: don’t. If you already have Agent Builder workflows, plan the move now.

## The OpenAI Agents SDK, including TypeScript

The Agents SDK is a code library for building agents in your own application. OpenAI’s docs describe a small set of primitives:

- **Agents:** a model with instructions and tools.
- **Tools:** turn your own functions into tools, plus support for MCP servers.
- **Handoffs and agents-as-tools:** one agent delegates to another.
- **Guardrails:** input validation and safety checks that run alongside the agent.
- **Sessions:** memory across turns.
- **Human in the loop:** built-in ways to pause for a person.
- **Tracing:** see every step for debugging and monitoring.
- **Sandbox and voice agents** for workspace tasks and low-latency spoken interactions.

It’s available in Python and TypeScript. The [TypeScript SDK docs](https://openai.github.io/openai-agents-js/) show the basic setup:

```
npm install @openai/agents zod
```

```
import { Agent, run } from '@openai/agents';

const agent = new Agent({
  name: 'Quote triage',
  instructions:
    'Classify the email as quote request, support or other. ' +
    'For quote requests, extract name, service and address.',
});

const result = await run(agent, emailText);
console.log(result.finalOutput);
```

The docs note that the SDK requires Zod v4 and that you set the `OPENAI_API_KEY` environment variable. From there you add function tools (for example, “create CRM deal”), guardrails and a human-approval step before anything is sent.

**Why TypeScript matters for small businesses:** if your website or internal tools already run on Node.js (Next.js, Astro or a serverless backend), the TypeScript SDK lets the agent live in the same codebase and deploy the same way.

OpenAI’s platform docs also list a managed **Agents API**, where OpenAI runs the agent infrastructure for long-running tasks, alongside the SDK and the lower-level Responses API. For most SMB builds, the SDK gives the right balance of control and effort.

## n8n AI agents: the workflow-first option

n8n is a workflow automation platform with an **AI Agent** node. You build a normal workflow (trigger, CRM lookup, email, Slack), and drop an AI agent step where judgment is needed. It can use OpenAI models or others.

**Good for:** agents that are one step in a bigger process, for example “when a form arrives, have the agent classify it and draft a reply, then route it.” It’s visual, self-hostable and easy to hand over. We cover it in hiring an n8n automation expert and our [n8n automation](https://www.micromarketing.dev/services/n8n-automation) service.

## Which one should a small business build with?

![Decision path for choosing an OpenAI agent option: internal team task, customer-facing or inside your app, or part of a larger workflow](https://www.micromarketing.dev/images/resources/gpt-agents-vs-openai-agentkit/choose-openai-agent-option-decision.webp)

Ask three questions:

1. **Is it an internal helper for your team, and are you on ChatGPT Business or Enterprise?** Start with a Workspace Agent.
2. **Does it face customers, live in your app or need your own approval logic and data store?** Build with the Agents SDK.
3. **Is the agent one step in a larger automation across several tools?** Use n8n with an AI Agent node, or an SDK agent triggered by n8n.

And one rule: don’t start anything new on custom GPTs or Agent Builder.

## How we build OpenAI agents for clients

Our [AI agent development service](https://www.micromarketing.dev/services/ai-agent-development) usually ends up in one of two shapes: an Agents SDK build in TypeScript or Python for customer-facing or app-embedded agents, or an n8n workflow with an AI step for back-office automations. Either way we scope permissions narrowly, add human approvals on anything customer-facing, test on your real examples and monitor runs after launch. We also build on other stacks, including Grok and open-source agents like [Hermes Agent](https://www.micromarketing.dev/resources/ai-automation/hermes-ai-agent-explainer), and pick per task. For the bigger picture, see our [AI automation services](https://www.micromarketing.dev/services/ai-automation).

## Frequently asked questions

### What are GPT agents?

“GPT agents” usually means AI assistants built on OpenAI’s GPT models that can take actions, not just chat. In 2026 that covers custom GPTs (being retired), Workspace Agents in ChatGPT, and agents built in code with the OpenAI Agents SDK.

### Is OpenAI AgentKit being discontinued?

Partly. OpenAI says it’s winding down AgentKit’s Agent Builder and Evals, which won’t be available from November 30, 2026. It recommends the Agents SDK for code-based workflows and Workspace Agents for prompt-based ones.

### Can I still create a custom GPT?

Not on personal ChatGPT plans (Free, Go, Plus or Pro). Business, Enterprise and Edu workspaces can still create GPTs where settings allow, but OpenAI plans to retire custom GPTs, with Enterprise retirement planned for December 11, 2026.

### Does the OpenAI Agents SDK support TypeScript?

Yes. There’s a TypeScript SDK installed with npm (`@openai/agents` plus `zod`) and a Python SDK. Both support tools, handoffs, guardrails, sessions, human-in-the-loop steps and tracing.

### Should a small business use n8n or the Agents SDK?

Use n8n when the agent is one step in a larger workflow across tools and you want something visual and easy to hand over. Use the Agents SDK when the agent lives inside your app or website, faces customers or needs custom approval logic.

## Not sure which OpenAI option fits?

Tell us what the agent should do, who it serves and which tools it touches. We’ll recommend the build path and the guardrails it needs. **[Book a free strategy call](https://www.micromarketing.dev/contact)**. The first consult is free. Or read how our [AI agent development](https://www.micromarketing.dev/services/ai-agent-development) process handles model choice, guardrails and monitoring.

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