A guide to your first biz dev custom GPT

What you’ll build

A custom GPT that drafts personalized follow-up emails after sales calls. You feed it a call recording or notes, and it generates a ready-to-edit email in your voice. Amanda says this cut her follow-up time from 15–20 minutes per email to about two minutes.

Time commitment

• Quick version (this guide): 30–45 minutes
• Full version (see original post): 4–6 hours for all five agents

The build (minimum viable version)

Step 1: Gather your email templates—10 minutes

Pull 3–5 follow-up emails you’ve already sent that represent how you want to sound. Save them in a single document with labels like ​“post-discovery call,” ​“post-intro call,” or ​“re-engagement.” These become the voice reference for your GPT.

Quick version: If you don’t have 3–5 saved, grab your 2 most recent follow-up emails from your sent folder. Two examples are enough to start.

You’re doing it right if: You have a document with at least 2 labeled email examples that sound like you at your best.

Step 2: Create the custom GPT—15 minutes

Open ChatGPT and ask it to help you write the system prompt:

Answer the clarifying questions ChatGPT asks. Then copy the generated prompt, go to ​“Create a GPT” in the ChatGPT sidebar, paste the prompt into the Instructions field, and upload your email template document as a knowledge file.

Quick version: Don’t overthink the prompt. Amanda’s approach is to get it roughly right, then refine after testing. If the first attempt produces bad output, delete the GPT and start again with clearer instructions.

You’re doing it right if: You can see the new custom GPT in your ChatGPT sidebar and it responds when you type ​“I just had a call with a marketing director at a mid-size company. Help me draft a follow-up.”

Step 3: Test with a real call—10 minutes

Take a recent call recording or your notes from a real meeting. Paste them into the custom GPT along with the person’s name, company, and what stage of your sales process they’re in. Review what comes back.

Quick version: If you don’t have a recording, type up 3–4 bullet points from your last sales call—who you met, what they need, and what you discussed. That’s enough for a useful test.

You’re doing it right if: The GPT produces a follow-up email that sounds roughly like you, references specific details from the call, and needs only light editing before sending.

You’re done when…

You have a custom GPT that takes call notes as input and produces a follow-up email draft that sounds like your writing. You should be able to edit the output in under five minutes instead of writing from scratch.