# ChatGPT, custom GPTs and Actions

Web page: https://academy.memberpress.ai/courses/ai-tool-guides/l1/

Lesson 1 of 4 in [AI Tool Guides: ChatGPT, Codex, Cursor and Grok](https://academy.memberpress.ai/courses/ai-tool-guides/), 12 min.

**What it is**

ChatGPT is OpenAI's assistant, on the web, on desktop and on mobile. Plans run from Free up to Pro, plus Business and Enterprise for teams; OpenAI's pricing page has the current list.

**When to pick it**

When your team already works in ChatGPT, or you want one place for chat, files and projects with OpenAI's models. For coding inside a repository, see the Codex guide.

**Setup**

1. Sign in at chatgpt.com, or install the desktop app.
2. Create a project for one piece of ongoing work. A project keeps chats, files, instructions and sources together.
3. Write project instructions; they apply across all of the project's chats.
4. Add the files the work depends on to the project's Sources. In the desktop app, a local project can attach a folder on your computer.

**A first real task**

In your new project, add your site's About page and pricing page to Sources, then ask: "Using only these sources, write the three questions a new visitor is most likely to ask, and answer each in two sentences." Check every answer against the pages.

**Connect it to your site or data**

- **MCP servers:** OpenAI's developer docs add one at chatgpt.com/plugins: the plus button, "Add custom MCP server", paste an HTTPS URL ending in `/mcp`, then "Create as a plugin". In a chat, type `@` and pick it. Try it with the academy's own server, `https://academy.memberpress.ai/mcp`. What you can add depends on your plan and workspace settings.
- **Custom GPTs and Actions:** an Action lets a custom GPT call your own REST API. It needs an OpenAPI schema, and its auth is none, an API key, or OAuth. But OpenAI is moving custom GPTs to plugins: a GPT's instructions become a skill and its files become a skill's reference files, while Actions don't transfer and have to be rebuilt, for example as a custom MCP server. For new work, start with an MCP server.

Checked against OpenAI's docs on 2026-10-14: [pricing](https://learn.chatgpt.com/docs/pricing), [projects](https://learn.chatgpt.com/docs/projects), [plugins quickstart](https://developers.openai.com/apps-sdk/quickstart), [Actions getting started](https://developers.openai.com/api/docs/actions/getting-started), [moving custom GPTs to plugins](https://learn.chatgpt.com/docs/migrate-custom-gpts).

## Try these prompts

- I run a membership site. Set up a ChatGPT project for it: suggest the project instructions and the five files I should add to its Sources.
- I have a custom GPT with Actions. Walk me through what changes when OpenAI moves custom GPTs to plugins.

Next: [OpenAI Codex](https://academy.memberpress.ai/courses/ai-tool-guides/l2/)