Custom GPT instructions for sales: write the rules once
Updated · By Robert Breen
Use this when your sales team keeps getting generic, pushy follow-ups from ChatGPT. Instead of a better one-off prompt, you write the rules once, as instructions for a Custom GPT or a ChatGPT Project, and every rep gets the same voice and the same limits. Fill in what you sell, who you sell to and your rules, and ChatGPT writes the instructions for you to paste in.
One timing note: OpenAI's Help Center says it plans to retire Custom GPTs, so for new work paste the same instructions into a ChatGPT Project. The rules are what matter, and they work in either place.
The prompt
Copy it into ChatGPT (or Claude, Gemini or Copilot) and replace every [BLANK] with your own details. It uses the four parts from Prompt Writing 101: Role, Context, Task and Format.
Role: You are writing the instructions for an AI assistant that drafts sales emails for [COMPANY]. Context: We sell [WHAT WE SELL] to [WHO WE SELL TO]. Reps use the assistant after [WHEN USED]. Our voice: [VOICE]. Rules it must always follow: [RULES]. Prices and features come only from the attached file called [REFERENCE FILE]. Task: Write the assistant's instructions in plain words, under four headings: Voice and tone, Structure, Content rules and Company context. Include a rule never to invent a price, discount, feature or result, and a rule to use a [bracket] for any detail the rep has not given. Format: Short bullet lists under each heading, under 300 words in total, written to the assistant as "you". No examples inside the instructions.
Fill in the blanks
[COMPANY]- Your company name.
[WHAT WE SELL]- Your product or service in one line.
[WHO WE SELL TO]- Your usual buyers, such as "small service businesses with 2 to 50 staff".
[WHEN USED]- The moment reps will use it, such as "a demo or discovery call".
[VOICE]- Three or four words or rules, such as "helpful, direct, short sentences, no emojis".
[RULES]- Your must-follow rules: length limit, one next step, price only if asked, banned pressure words.
[REFERENCE FILE]- The name of the playbook or price sheet you will upload as knowledge.
Example, filled in
A made-up example from the free lesson Build a Custom GPT That Writes Sales Follow-Up Emails. Northwind Scheduling Software is the made-up company in the sales Custom GPT lesson, where you build a Sales Follow-Up Writer and attach Northwind-Sales-Playbook.pdf. Here is how the sales lead might fill in this prompt to get instructions like the ones in the lesson.
Role: You are writing the instructions for an AI assistant that drafts sales emails for Northwind Scheduling Software. Context: We sell online scheduling software to small service businesses: cleaning companies, salons, lawn care crews and repair shops. Reps use the assistant after a call or a demo. Our voice: a helpful rep who listened, direct, short sentences, no emojis, no all caps. Rules it must always follow: emails under 150 words, one next step with a clear ask, give the price only if they asked, never use pressure words like act now or limited time, never promise results. Prices and features come only from the attached file called Northwind-Sales-Playbook.pdf. Task: Write the assistant's instructions in plain words, under four headings: Voice and tone, Structure, Content rules and Company context. Include a rule never to invent a price, discount, feature or result, and a rule to use a [bracket] for any detail the rep has not given. Format: Short bullet lists under each heading, under 300 words in total, written to the assistant as "you". No examples inside the instructions.
What a good answer looks like
- Every rule you listed appears once, under the right heading.
- "Never invent a price or a discount" is there word for word or close to it.
- The instructions tell the assistant to use brackets for missing details instead of guessing names or team sizes.
- It stays under 300 words, so the rules are easy to update.
How to check it before you use it
An AI draft can sound right and still say something you never told it. Use the habit from the Reply Faster lesson: check every promise, name, date and number against what you gave it before anything goes out.
- Paste the instructions into a Project or GPT, upload the playbook, and test with a real call note.
- Ask about a price that is not in the playbook. The assistant should say it does not have it, not make one up.
- Have one rep use it for a week and tell you which rule they keep overriding.
Why this prompt works
Generic prompts give generic, pushy emails because the AI fills gaps with sales clichés. Written instructions plus a reference file close those gaps once, for the whole team, which is the whole point of the Custom GPT for sales lesson.
Practice it in the free lesson
Replace Your Custom GPT with a ChatGPT Project: Custom GPTs are retiring (Enterprise: December 11, 2026). Copy your GPT's instructions, starters and files, rebuild it as a ChatGPT Project with project-only memory, and test it on a real customer question. You do every step yourself in a practice copy of ChatGPT, and nothing touches your real accounts.
Also useful: ChatGPT Projects: Keep Your Brand Voice, Files and Instructions in One Place
Terms used here
Related prompts
- Sales follow-up after demo prompt: Write a follow-up after a sales demo from your call notes: the features that fit, price only if asked, one next step. A ChatGPT…
- Discovery call recap email prompt: A copy-ready prompt that turns a call transcript into a same-day recap email and CRM notes, using only what the prospect…
- Stalled deal follow-up prompt: Restart a deal that went quiet after pricing or a proposal: address the likely blocker in the prospect's own words and ask for a…
- Demo request reply prompt: Reply to a demo request fast with a ChatGPT prompt that shows you read it, answers questions only from your product facts and…
More sales prompts
- Upsell offer email prompt: Offer an existing customer one related service that fits what they bought or told you, with your real price, the reason it fits…
- Account plan prompt: Build a 90-day plan for a current customer from your notes: goals in their words, people, risks, questions to confirm and dated…
- Call notes to CRM update prompt: Turn messy sales call notes into a clean CRM entry: summary, needs, objections, next step with a date, and a deal stage you…
Frequently asked questions
- What are good custom GPT instructions for sales?
- Clear rules on voice, email structure and content: one next step, a length limit, price only if asked, no pressure words and never invent a price, discount or result. Pair them with a playbook file.
- Can I still build a custom GPT for sales?
- OpenAI says it plans to retire Custom GPTs, and new GPT creation is limited on personal plans. Put the same instructions and files in a ChatGPT Project instead.
- Should prices go in the instructions or a file?
- In a file, such as a playbook PDF. Prices change, and keeping them in one uploaded document makes them easy to update and easy for the assistant to quote exactly.