How to Connect ChatGPT to WordPress to Build and Run Your Site

With Fabrement, ChatGPT does more than answer questions about WordPress: it builds and runs the site. It creates custom Gutenberg blocks, adds custom fields and site-wide settings, turns Figma frames into WordPress pages, sets up SEO with Yoast and translates the site with WPML. After launch, you manage all of it from the chat, without opening wp-admin. Anything beyond that, you can add yourself: what the agent builds is ordinary WordPress code you own, like a custom theme made for your site. To get there, you connect ChatGPT to the site over MCP.

ChatGPT can work on a WordPress site through MCP: you ask in the chat, and the change happens on the site. OpenAI gives you two ways to do it. ChatGPT itself, in the browser, for everyday changes in plain words. And Codex, OpenAI’s coding agent, which runs in the ChatGPT desktop app, in a terminal and in your code editor, for building and bigger jobs.

This guide shows the steps for Fabrement in each of them: ChatGPT on the web, Codex in the desktop app, the Codex CLI and IDE extension, and the application password route for sites and machines where OAuth is not an option.

The whole connection in 2 minutes and 39 seconds: Developer mode, the MCP app, OAuth sign-in, and a first change on a live page from the chat.

Key takeaways

ChatGPT connects with OAuth. Create an MCP app with your site’s address (after turning on Developer mode, if your plan needs it) and approve access on your own site. No password to copy.
It needs a paid ChatGPT plan and works in ChatGPT on the web, not in the mobile app. On a workspace, an administrator may need to grant permission first.
Codex is a separate connection. Connecting ChatGPT does not connect Codex. Codex in the desktop app, the CLI and the IDE extension share one configuration, so you connect it once for all three.
No OAuth? Use an application password. For a site without HTTPS, or Codex on a server. The key goes in the Authorization header, never in the Bearer token field.
The site must be reachable over HTTPS. ChatGPT on the web needs a public address; Codex on your computer can also reach a local site with a trusted certificate.

On this page

Which way should you use?
Before you start
1. Connect ChatGPT
2. Connect Codex in the ChatGPT desktop app
3. Connect the Codex CLI or IDE extension
4. Without OAuth: an application password
When it does not work
Revoking access
What ChatGPT and Codex can do once connected

Which way should you use?

	How it signs in	Needs	Best for
ChatGPT (web) Recommended	OAuth: create the MCP app once, then approve on your site	A paid ChatGPT plan (Developer mode on some plans), a public HTTPS site	Everyday changes in plain words, nothing to install
Codex in the ChatGPT desktop app	OAuth: add the URL, then Authenticate and approve on your site	The ChatGPT desktop app, an HTTPS site	Building sections and pages, bigger jobs
Codex CLI or IDE extension	OAuth, with two commands	The Codex CLI or the extension in VS Code or Cursor	Developers who work in a terminal or a code editor; local sites with a trusted HTTPS certificate
Application password	A key in the Authorization header	An administrator account	Sites without HTTPS, OAuth turned off, or Codex running on a server

Before you start

WordPress 6.9 or newer, PHP 8.0 or newer, and an administrator account.
Fabrement installed and the site signed in to the Fabrement service: block code is checked and stored there, so nothing can be saved until the site is signed in.
For ChatGPT: a paid ChatGPT plan, and a site reachable on the internet over HTTPS.
For Codex: the ChatGPT desktop app, the Codex CLI or the Codex extension, signed in with your ChatGPT account or an OpenAI API key.

Every connection detail below comes from Fabrement → MCP Connection in wp-admin, on the ChatGPT or Codex card. Copy it from there rather than typing it: the server name and address are specific to your site.

1. Connect ChatGPT

In Fabrement → MCP Connection, pick ChatGPT. The card walks you through the same steps as below, with the server name and URL to copy.

Fabrement MCP Connection, ChatGPT card: enable Developer mode if needed, then Open ChatGPT Plugins

Step 1: Enable Developer mode, if your plan needs it

Not every account needs this, and whether yours does depends on your ChatGPT plan. If Create app already shows on ChatGPT’s Plugins page, skip this step. Otherwise, in ChatGPT’s settings, open Security and login and switch Developer mode on. If your workspace uses the Apps layout, look under Settings → Apps → Advanced settings instead; an administrator may need to grant permission first.

ChatGPT settings, Security and login: the Developer mode switch turned on

Step 2: Create the MCP app

Press Open ChatGPT Plugins on the ChatGPT card. On the Plugins page, click the plus (+) button next to Search plugins and choose Create app. In the New Plugin dialog, click Create MCP App at the bottom left.

ChatGPT Plugins page: the plus button menu with Create app

ChatGPT New Plugin dialog with the Create MCP App button

Fill in the Name and paste the MCP server URL from the ChatGPT card into Connection. Leave Authentication on OAuth, tick I understand and want to continue (ChatGPT asks this for every custom MCP server), and press Create.

ChatGPT New Plugin form: Name, Server URL, Authentication OAuth and the I understand and want to continue checkbox

Step 3: Approve access on your site

ChatGPT sends you to your WordPress site. Sign in as an administrator if asked, then press Allow access. Your WordPress password is not shared: ChatGPT receives a token that only works through the Fabrement MCP server.

WordPress authorization page for an AI client, showing Full Fabrement MCP access and the Allow access button — The approval page names the client that asks: Claude in this example, ChatGPT in yours.

Step 4: Check the connection

Open a new chat, turn the app on for the chat if it is not on already, and ask ChatGPT to list the blocks on your site. If it answers with your real blocks, you are connected.

ChatGPT treats a custom MCP app as a developer feature and shows its own warning about it. Fabrement’s operations tell the agent to ask you in the chat before publishing or moving pages to the trash, but treat the connection like an administrator: connect it only in your own account.

2. Connect Codex in the ChatGPT desktop app

Step 1: Copy the server name and URL

In Fabrement → MCP Connection, pick Codex and stay on the Recommended tab. Copy the server name and URL it shows. Use Codex in the ChatGPT desktop app or the Codex extension for VS Code or Cursor: Codex on the web cannot connect to your own MCP server.

Fabrement MCP Connection, Codex card on the Recommended tab: open the Codex app in the ChatGPT desktop app or the VS Code or Cursor extension

Step 2: Add an MCP server in Codex

In the ChatGPT desktop app, open Codex’s Plugins page, press Add and choose Add MCP server.

Codex Plugins page in the ChatGPT desktop app: Add menu with Add MCP server

Step 3: Fill in the form

In Connect to a custom MCP, enter the name, choose Streamable HTTP, paste the URL and press Save. Leave the Bearer token and header fields empty: OAuth needs none of them.

Codex Connect to a custom MCP form: Name, Streamable HTTP and URL

Step 4: Authenticate and approve

In the list of MCP servers, press Authenticate next to your site. Your WordPress site opens the same approval page as for ChatGPT: sign in as an administrator if asked, then press Allow access.

Codex MCP servers list with the Authenticate button next to the Fabrement server

Step 5: Check the connection

Start a new Codex session and ask it to list the blocks on your site. If it answers with your real blocks, you are connected.

3. Connect the Codex CLI or IDE extension

On the Advanced tab of the Codex card, Codex (OAuth) offers three ways to add your site without the app form; pick one. The quickest is a terminal: run both commands, the first adds your site to Codex and the second opens the browser to approve access. They have this shape, with your own name and address filled in:

codex mcp add fabrement-your-site --url "https://your-site.com/wp-json/fabrement/v1/mcp"
codex mcp login fabrement-your-site

The card also shows the other ways, such as a config.toml entry if you prefer to edit the file. Whichever you pick, the desktop app, the CLI and the IDE extension all pick the site up, and since Codex connects from your own computer, it also reaches a local site with a trusted HTTPS certificate.

Fabrement MCP Connection, Codex card on the Advanced tab: Codex (OAuth) with the codex mcp add and codex mcp login commands

4. Without OAuth: an application password

Use an application password with Codex when OAuth is not an option: the site has no HTTPS, OAuth is turned off, or Codex runs where no browser can open to approve access, such as a server. ChatGPT on the web connects with OAuth only.

In Fabrement → MCP Connection, pick Codex, open the Advanced tab, then Application password, and press Generate application password.
Pick one form: a codex mcp add command for PowerShell or bash, the URL and header for the app’s form, or a ~/.codex/config.toml entry.
In the app’s form, put the key in the Authorization header and leave the Bearer token field empty. The key is a Basic authorization header, so the Bearer field makes every request fail with 401.

The config.toml entry has this shape:

[mcp_servers.fabrement-your-site]
url = "https://your-site.com/wp-json/fabrement/v1/mcp"
http_headers = { "Authorization" = "Basic YOUR_KEY" }

The password is shown once and works until you revoke it. Treat it like an administrator password: never paste it into a screenshot, a chat or a shared document, keep it out of any config file you commit to Git, and disconnect it in the Connection access card when the work is done. On Windows the commands use PowerShell; start Codex from that same terminal, because apps that are already running do not pick up new environment values.

When it does not work

What you see	What it is
Create app is missing in ChatGPT	Developer mode is off. Turn it on in ChatGPT’s settings under Security and login, or under Settings → Apps → Advanced settings on a workspace; an administrator may need to grant permission.
The app is not available in the ChatGPT mobile app	Custom MCP apps work in ChatGPT on the web only. Use a browser.
ChatGPT cannot reach the site	The site is local, not on HTTPS, or blocked by a firewall. ChatGPT on the web needs a public HTTPS address; use Codex for a local site.
Authenticate does nothing, or the approval page does not open	The site has no HTTPS, or OAuth is turned off in the Connection access card. Switch it on, or use an application password with Codex.
401, or «incorrect password»	With an application password: the key went into the Bearer token field instead of the Authorization header, the setup was cut off when copied, or the key was revoked. Generate a fresh one.
Codex on the web cannot find the server	Codex on the web cannot connect to your own MCP server. Use Codex in the ChatGPT desktop app, the CLI or the extension for VS Code or Cursor.
The server is missing from Codex’s `/mcp`	It was added to a project’s `.codex/config.toml`, which only applies inside that project. Add it with the commands above to use it everywhere.
Connected, but no tools	The chat or session started before you connected: open a new one. In the CLI, `codex mcp list` shows whether the server is there.
Codex times out	A slow host. Raise `startup_timeout_sec` (default 10 seconds) or `tool_timeout_sec` (default 60 seconds) for the server in `config.toml`.

Revoking access

OAuth access and application passwords both stay active until you revoke them. The Connection access card on Fabrement → MCP Connection lists every connection to the site, whichever client set it up. Press Disconnect next to one to revoke it, and remove the app in ChatGPT or the server in Codex too. Switching OAuth off disconnects every OAuth client at once and leaves application passwords as they are.

What ChatGPT and Codex can do once connected

The same as any other agent on the site: build new blocks as code on the site’s design system, create pages from existing sections, edit text and images, manage menus, forms, templates, custom post types, fields and SEO. They work through a fixed set of operations, not a shell: no file access beyond the blocks they write, a read-only database operation, and publishing as a separate step from saving. What that looks like in daily work is in three weeks of WordPress without wp-admin.

FAQ

Frequently asked questions

Which ChatGPT plan do I need to connect WordPress?

A paid plan. Whether you also need to turn on Developer mode depends on the plan: if Create app already shows on ChatGPT’s Plugins page, you do not. On a workspace, an administrator may need to grant permission first. Codex is included in ChatGPT plans and can also run on an OpenAI API key.

Can I manage my WordPress site from the ChatGPT mobile app?

Not at the moment. MCP apps created in Developer mode work in ChatGPT on the web, not in the mobile app, and ChatGPT’s agent mode does not use them. Work from ChatGPT in a browser, or connect Claude, whose connector is also available in its mobile app.

Does connecting ChatGPT also connect Codex?

No. Codex now runs inside the ChatGPT desktop app, but Fabrement treats ChatGPT and Codex as separate clients: each one has its own card in Fabrement → MCP Connection and its own approval. Connect the one you use, or both, and each appears on its own line in the Connection access card.

Why must the Bearer token field stay empty when I use an application password?

The application password is sent as a Basic Authorization header. Codex’s Bearer token field sends the key in a different format, which WordPress rejects with a 401 error. Put the Authorization header in the header field and leave the Bearer token field empty. With OAuth there is nothing to paste at all.

Can I connect Codex and Claude Code to the same site?

Yes. Connect each one separately, with OAuth or its own application password. Each connection gets its own line in the Connection access card on Fabrement → MCP Connection, so you can see which one was used last and disconnect one without cutting off the other.

Is it safe to give an AI agent access to my site?

Treat the connection like an administrator: whether it uses OAuth or an application password, the agent acts as your administrator user, with write and delete access to content. Connect only clients you trust, work on staging when the change is significant, keep versions so a change can be rolled back, disconnect the agent in the Connection access card when the work is done, and review anything that touches payments, authentication or personal data yourself.

Using another client? See how to connect Claude to WordPress. For Cursor, see how to connect Cursor to WordPress.

Sources

Developer mode and MCP apps in ChatGPT, OpenAI Help Center (plans, web only, creating an MCP app)
MCP documentation for Codex, OpenAI (codex mcp add, codex mcp login, Authenticate, config.toml keys and defaults, the shared configuration)
Fabrement’s own AGENTS.md (plugin version 1.4.0) and the MCP Connection screen

Checked on 30 September 2026, with Fabrement 1.4.0. If a step has changed, tell us and we will correct it.