Custom GPT for Marketing: Build a Team-Ready Playbook

Turn your brilliance into a scalable AI team asset.

Lisa Larter

August 7, 2025

Read time: 5 mins

Post Summary

Stop repeating your brand guidelines and start building a Custom GPT that actually knows you. By training a private AI on your unique voice and business nuances, you create a shared playbook that enables your team to produce consistent, high-quality content without the constant re-teaching. It’s time to move beyond one-off chats and turn your thought leadership into a scalable strategic asset that stays with your business forever.

Are you having one-off chats with ChatGPT, or are you building a Custom GPT your team can actually use?

A GPT is a Generative Pre-Trained Transformer.

ChatGPT is one-size-fits-most when it comes to using AI for your business, but you can create and train Custom GPTs for specific use cases.

When you’re subscribed to ChatGPT Pro, you can train a Custom GPT to be the playbook your team uses to create marketing materials.

It lets you capture all of the nuances of a project, task, and brand identity that you can share across your team, and have it ready to onboard new team members seamlessly.

Public GPTs vs. Private GPTs

A public Custom GPT is when someone allows anyone to use it.

A private Custom GPT is one where only you and anyone with access to your workspace can use it.

I’m a fan of using both.

I use public GPTs for generic, low-risk ideation. For example, I’ve used a public GPT that was built just to create great hooks. Why would I create my own GPT on hooks when I can use this one to help me create better hooks?

I use my private Custom GPT for when I need something to sound like me and be factually correct about my business. I’m also able to have more control over keeping the information I used private when I use my own GPT.

As a rule of thumb, do not upload any sensitive information to a public GPT that you do not want to be on public record.

What Can You Use A Custom GPT For?

When you encounter a task or project you do at least once a week, there’s an opportunity to create a Custom GPT, whether it’s prepping for a podcast or creating content.

There’s a podcast host, Dan Sanchez, who created a Custom GPT called My Showrunner. It’s trained to help him prep to host his podcasts. This is an example of a project application where there’s a series of questions he’s programmed his Custom GPT to ask him to cut down on his prep time.

When it comes to a marketing application, you can train a Custom GPT on your voice and business. It’ll be able to produce content that upholds your values and sounds like you.

Instead of retraining and reteaching your style, voice, and brand values to each new team member, they’re able to hit the ground running, creating blogs, social content, and newsletters with a Custom GPT marketing assistant.

How To Set Up A Custom GPT

Calibrate:
Ask, “What do you know about me/my business?” Correct errors.
Interview:
Tell it, “Ask me 30 questions, one at a time, and ask clarifying questions after each.” Include business and personal insights, such as interests, sense of humor, hobbies, because those show up in your thought leadership and offers.
Guardrails:
Document voice dos and don’ts. If you don’t use em dashes, say so. If you like ellipses, like I do, let it know you only use them 1–2 times per piece. Specify who you never quote and who you often quote.
Gold Standard:
Upload 5–8 of your best pieces and explain why they work. What is the hook, point of view, proof, CTA, or tone that sets them apart? These become the standard that the model learns from.
Access and ownership:
Host the Custom GPT inside your workspace and set permissions. Keep ownership with the business, grant access when people join, revoke it when they leave.

A Custom GPT streamlines your workflow because once you load it with your best writing, brand voice, offers, quirks, and clear guardrails, it can reference all of that on every task, and you can share the same GPT with your whole team.

Yes, setup takes real time (feeding samples, teaching brand identity, setting rules), but once it’s done, everyone drafts from the same playbook, and you stop re-teaching the rules every time the team changes.

Perks Of A Custom GPT

Centralize A Working Knowledge Base

I host the Custom GPT inside our workspace, set permissions, and keep ownership in the business, not in any one person’s account. If someone joins, they get access. If someone leaves, the know-how stays.

Recalibrate On A Rhythm

I can run quick check-ins monthly or when priorities shift to update content pillars, offers, and voice guardrails. If the model drifts, I correct it. If we change direction, I teach it.

Set The Gold Standard

Instead of everyone having an opinion on which social content or newsletter they feel is strongest, you’re able to identify and update your best pieces and what made them effective. This keeps everyone operating under the same proven standards that have given you results in the past.

If you want this set up for yourself and your team, then learn about custom GPTs and more practical marketing applications in my course, AI-Driven Marketing Made Easy.

Our first session is on August 19th.

Let’s move on from one-off chats and dive into AI’s larger potential of building a Custom GPT that streamlines and skips the learning curve of your marketing processes.