ChatGPT Custom Instructions that stay short enough to work
Write the two boxes (who you are, how to reply), test them on a fresh chat, and cut anything ChatGPT ignores. Official Custom Instructions only.
In short: This page contains 15 copy-paste ready prompts, organized into 5 categories with a description and pro tip for each. The first 5 prompts are free instantly, no signup needed. Hand-curated and tested by the AI Academy team.
Write the two boxes
3 promptsAbout you, from facts
1/15✨ What it does
ChatGPT drafts a 120-word About you box from the facts you listed. Paste it into Custom Instructions. Fill [VERIFY] yourself.
Draft the About you Custom Instruction from these facts only: [ROLE], [STACK], [AUDIENCE], [THINGS I NEVER WANT]. 120 words. No biography. No invented employers. Tag gaps [VERIFY].
Pro tip: If you paste a resume, it will overfit. Four facts beat a life story.
How to reply
2/15✨ What it does
ChatGPT drafts the How to reply box with cite and [VERIFY] rules. Paste it. Start a new chat to test, not the current one.
Draft How would you like ChatGPT to respond for [ROLE]. Rules: [FORMAT], cite when I paste a source, [VERIFY] invented numbers, no pep, no emojis unless I ask. 150 words.
Pro tip: Custom Instructions apply to new chats. Old threads will not pick up the change.
Work vs personal profiles
3/15✨ What it does
ChatGPT writes two instruction sets and keeps client names in work only. Save work on the account you use for [COMPANY].
I need two Custom Instruction sets: work ([WORK FACTS]) and personal ([PERSONAL FACTS]). Write both. Mark which box they go in. Do not mix a work client name into personal.
Pro tip: One account, two lives: you will leak a client into a joke chat. Split accounts if you can.
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Test
3 promptsFresh-chat test
4/15✨ What it does
ChatGPT answers [QUESTION] as if the instructions were on, then lists 4 ignores. Tighten those 4 lines. Test again in a real new chat.
Treat this as a brand new chat with my Custom Instructions: [PASTE INSTRUCTIONS]. I ask: [QUESTION]. Answer as you would with those instructions, then list 4 places you ignored them.
Pro tip: The ignore list is the product. Edit those lines, do not add a fifth essay.
Refusal still works
5/15✨ What it does
ChatGPT refuses [BAD REQUEST] using your instructions or flags a missing never-do. Add the line if it marked [VERIFY].
With these Custom Instructions: [PASTE], refuse this request the way the instructions require: [BAD REQUEST]. If the instructions are silent, write a safe refusal and mark [VERIFY] that I should add a never-do line.
Pro tip: People forget that Custom Instructions can make the model too eager. Test a request you want refused.
Length test
6/15✨ What it does
ChatGPT answers [Q] in 6 lines under your instructions. If it rambles, your How to reply box is too soft. Add a hard line cap.
I asked for a 6-line answer. Instructions: [PASTE]. Question: [Q]. Reply in 6 lines. If you need more, say so in line 6 instead of rambling.
Pro tip: Put the line cap in the instructions, not only in the question. Questions get forgotten. Instructions get reused.
Shrink
3 promptsCut to 800 characters
7/15✨ What it does
ChatGPT shrinks each box under 800 characters and lists deleted lines. Paste the short version. Restore one deleted line only if a test fails.
Here are my Custom Instructions: [PASTE]. They are too long. Rewrite each box under 800 characters. Keep never-do and [VERIFY]. Show deleted lines as bullets.
Pro tip: Long Custom Instructions get partially ignored. Short and mean wins.
Kill contradictions
8/15✨ What it does
ChatGPT lists contradictory lines and which to keep. Delete the loser. Do not add a third rule to paper over it.
Find contradictions in these Custom Instructions: [PASTE]. List each pair and recommend which line to keep. Do not add new rules.
Pro tip: Be thorough and be brief in the same box is how you get neither.
One job per line
9/15✨ What it does
ChatGPT rewrites your instructions as numbered verbs. Paste that list. If a line cannot fail a test, delete it.
Rewrite these instructions so each line is one verb: [PASTE]. Number them. Drop adjectives that are not testable.
Pro tip: Use British spelling is testable. Be world class is not.
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Special cases
3 promptsManager who hates fluff
10/15✨ What it does
ChatGPT writes a 100-word How to reply from [NOTES] with decision-first and a ban list. Paste it. Ask a real question and check the first line is a decision.
Write How to reply for a manager who wants: decision first, then 3 bullets, then risks. Ban: delve, tapestry, landscape, excited to. 100 words from [NOTES].
Pro tip: If the first line is a throat-clear, the instructions lost. Put decision first as the first sentence of the box.
Developer defaults
11/15✨ What it does
ChatGPT writes developer Custom Instructions for [STACK] that ban invented flags. Paste them. Test with a CLI question you know.
Write Custom Instructions for a developer. Stack: [STACK]. Rules: show commands I can run, no invented flags, say when you are guessing an API. 140 words.
Pro tip: The no invented flags line saves hours. Keep it even if the rest changes.
Writer defaults
12/15✨ What it does
ChatGPT writes writer Custom Instructions from [STYLE NOTES] with your ban list. Paste them. Run a rewrite test on a paragraph you own.
Write Custom Instructions for a writer. House rules from [STYLE NOTES]. Ban em dashes and the words: [BAN]. Ask for a [VERIFY] on any quote I did not paste.
Pro tip: If you do not ban the dash, you will spend your life deleting it. Put it in the box.
Maintenance
3 promptsQuarterly review
13/15✨ What it does
ChatGPT proposes an add, cut, or keep diff from [NOTES]. Apply three changes at most, then open a new chat and test the result.
Here are my Custom Instructions: [PASTE]. Here is what annoyed me this quarter: [NOTES]. Propose a diff: add, cut, keep. No new personality.
Pro tip: Review when you are annoyed, not on a calendar. The annoyance is the spec.
Export for a teammate
14/15✨ What it does
ChatGPT turns your instructions into a 10-line teammate starter with [BRACKETS]. Send that, not your live box with client names.
Turn my Custom Instructions [PASTE] into a 10-line starter a teammate can adapt. Replace my company names with [BRACKETS].
Pro tip: Do not screenshot Custom Instructions that contain a client. Bracket them.
Turn them off to debug
15/15✨ What it does
ChatGPT writes a 5-step debug to isolate Custom Instructions on [TASK]. Run it. If the task works with them off, the box is the bug.
I think Custom Instructions are breaking [TASK]. Write a 5-step debug: disable, new chat, minimal prompt, compare, re-enable one line at a time.
Pro tip: People blame the model. Half the time it is a leftover be detailed from 2024.
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