ChatGPT MCP plugin for on-brand copy, images, video and audio

Install the plugin

ChatGPT calls its integrations plugins. Older guides call them connectors or apps and send you to Developer Mode, which you no longer need. The Rainbrand plugin connects ChatGPT to Rainbrand's MCP server, so ChatGPT can list your brands and request Briefs and Reviews.

The link opens the plugin's page in ChatGPT's plugin directory. Select Install plugin, then Connect when ChatGPT asks, and sign in to Rainbrand or create an account.

Then start a new chat and check which account is connected. If you use more than one Rainbrand account, do this before anything else.

Show me which Rainbrand account is connected.

Which ChatGPT plans can use it

The plugin directory is on every ChatGPT plan. OpenAI says whether you can install a particular plugin depends on your plan, your workspace, your role and your region.

Personal plans

You install plugins yourself.

Business

Apps are on by default, and admins manage which plugins are available.

Enterprise and Edu

Admins choose which plugins each role can use. If Rainbrand shows Disabled by admin, ask your ChatGPT admin.

Pick a brand, or add one

If your team already has brands in Rainbrand, ask ChatGPT to list them. To add one, give ChatGPT what defines it: a website, a brand guide, written rules, logos or images. Upload files through Rainbrand's file picker, which opens in the chat. A brand is usually ready in about 90 seconds.

Add a brand in Rainbrand from [your website] and the files I upload. Wait until it's ready, then show me its name and a summary of its guidance.

Write the newsletter section

Ask for a Brief before ChatGPT drafts anything. Describe the task, the audience and the format, because Rainbrand picks the guidance and assets for that task rather than sending the whole brand. I used Teenage Engineering's brand to write a newsletter section introducing the OP–XY to people who already own an OP-1 field.

Request a Rainbrand Brief for Teenage Engineering. The task is a short email newsletter section, about 120 words, introducing the OP–XY to people on the mailing list who already own an OP-1 field. Wait for the Brief and show me its guidance. Then write the section using it. Only claim features that the Brief or teenage.engineering supports.

The Brief described the voice as precise, informed and quietly playful. It said to introduce the OP–XY without calling it an upgrade or a replacement for the OP-1 field, and to keep both product names exactly as the brand writes them. It also said what it didn't know: the brand holds no verified OP–XY specifications, so it sent ChatGPT to teenage.engineering to check each feature before writing it.

ChatGPT then listed where each feature came from on teenage.engineering, and noted that it had kept the copy from calling the OP–XY an upgrade.

Make the header image

ChatGPT can make an image itself or through Rainbrand. Both routes start from a Brief, which for an image includes reference images such as product photos.

I asked for Rainbrand's AI Gateway, but ChatGPT made this image with its own image tool, which uses your ChatGPT plan instead of Rainbrand credits. The image stays in ChatGPT, so it has to be uploaded to Rainbrand before Rainbrand can animate or review it. Images made through Rainbrand are saved there and go straight to the next step.

Request a Rainbrand Brief for Teenage Engineering for a 1536×1024 header image for that newsletter section: a product-led still life of the OP–XY, with no added text. Show me the Brief's reference images. Then generate the image through Rainbrand's AI Gateway with GPT Image 2.5 Flare.

Turn the image into a video and a voiceover

Rainbrand's AI Gateway also makes video and audio, so the same chat can take the work into other formats. Tell ChatGPT which image to start from, the length and the shape. I asked for a 5-second clip from the header image and a short voiceover in the brand's voice.

Make a 5-second 9:16 video from that header image through Rainbrand's AI Gateway with Seedance 2.5. Keep the camera slow while the display lights up and the red record light comes on. Then write a one-line voiceover from the copy Brief and generate it with Eleven v4.

Because ChatGPT had made the header image itself, it opened Rainbrand's uploader in the chat, and I uploaded the image there. Seedance kept the image's 3:2 shape rather than the 9:16 I asked for. The voiceover came out at 6 seconds, a second longer than the clip.

Check the Instagram post against the brand

Reviews are most useful on designed pieces, like a social post with a headline and a logo. I asked for an Instagram post for the OP–XY and a Review of all four checks.

Request a Rainbrand Brief for Teenage Engineering for a portrait Instagram post: “meet OP–XY” and the OP–XY on a light background, with the logo. Generate it through Rainbrand's AI Gateway with GPT Image 2.5 Flare, then request a Review for colour, typography, logo and copy.

It passed all four checks on the first try. In an earlier test through Rainbrand's API, the same request failed three: OP-XY set with a hyphen, the brand name typed out instead of the logo, and the wrong font for that name. The one thing left is the shape. The image came out 2:3, taller than Instagram's 4:5 portrait, so it needs cropping before posting, and ChatGPT pointed that out itself.

Colour

Pass: the monochrome palette and clean contrast match the brand.

Typography

Pass: a light sans-serif headline with the right letter shapes and spacing.

Logo

Pass: the primary logo, sharp, correctly proportioned and with enough clear space.

Copy

Pass: the exact headline "meet OP–XY", including the en dash.

Why not keep the brand in a custom GPT?

A custom GPT keeps the brand in ChatGPT only, and OpenAI retires custom GPTs on December 11, 2026. Migrating turns the GPT into a private plugin, which still lives inside OpenAI's tools. A brand in Rainbrand is one source for every agent you connect: ChatGPT, Codex, Claude, Cursor, and your own product through the API, which returns the same Briefs. When the brand changes, you edit it once and each agent uses the new version on its next task, instead of someone re-uploading files to every GPT and project.

It's also quicker to set up. Rainbrand builds the brand from a PDF or your website in about 90 seconds on average, while a custom GPT needs its instructions written and its files uploaded by hand.

Open Rainbrand's file picker. I'll upload the knowledge files from our brand GPT: the brand book PDF, the logo files and the voice guide. Add a brand from them, using the GPT instructions I paste below as written guidance. Wait until it's ready and summarise its guidance.

What it can't do in ChatGPT

Files you attach to a ChatGPT message don't reach Rainbrand. Upload them through Rainbrand's file picker in the chat, or share a public link. Images ChatGPT makes with its own image tool stay in ChatGPT, so you upload one before Rainbrand can review it. Reviews check images, including the words in them, but not plain text like the newsletter section.

Adding Rainbrand yourself as a custom MCP server works on Business, Enterprise and Edu, on the web only. Pro accounts can add one with read and fetch permissions only. Rainbrand doesn't read or update a custom GPT or a ChatGPT project, so moving a brand GPT is a one-time copy.

Fix common problems

Rainbrand isn't in the plugin list

Check your plan and workspace settings above. In a managed workspace, a plugin that's turned off shows Disabled by admin. In Codex, directory changes can take up to six hours to appear.

ChatGPT answers without Rainbrand

Type @ and choose Rainbrand, or ask for a Rainbrand Brief by name.

A Brief or brand is still processing

Ask ChatGPT to check the same Brief or brand again. Starting the task over can create a duplicate.

Rainbrand can't open a file

Upload it through Rainbrand's file picker or share a public link. Attachment links from ChatGPT are private.

Sign-in fails or tools are missing

Reconnect Rainbrand from its plugin page and sign in again.

Out of credits

Follow the link in the error to add credits or upgrade.

More fixes are in Rainbrand's troubleshooting guide.

Questions

Does the plugin work in Codex?

Yes. ChatGPT and Codex share one plugin directory, so Rainbrand works in Codex in the ChatGPT desktop app and in Codex CLI, where /plugins opens the directory. Codex CLI can also connect to the server directly with codex mcp add rainbrand --url https://mcp.rainbrand.com/mcp.

Is a plugin the same as a ChatGPT connector or app?

OpenAI first called these integrations connectors, then apps. Today an app connects ChatGPT to one service, and a plugin packages one or more apps, skills or both for a job. To set up Rainbrand, install its plugin.

Do I need to paste brand guidelines into ChatGPT projects?

No. The brand stays in Rainbrand, and any chat can request a Brief from its current version. If you use projects, keep campaign facts and drafts there.

Can my team use the same brands?

Yes. Brands in a Rainbrand team are available to everyone in it, in whichever agent they connect. Each person installs the plugin and signs in with their own Rainbrand account.

What does it cost?

Your ChatGPT plan covers ChatGPT, including its own image generation. The plugin works on every Rainbrand plan, and Briefs, Reviews and generations through Rainbrand use Rainbrand credits. Plans and credit prices are on our pricing page.