ChatGPT Custom Instructions for Business: 15 Examples to Copy

ChatGPT custom instructions are a standing note, saved once under Settings and Personalization, that the assistant reads before every chat. For a business the useful version has four lines: what the business is and who it sells to, how answers should look, what it must never do, and one sample of your writing. This guide gives 15 examples to copy, the six things to leave out, and the same setting in Claude, Gemini, Copilot and Jobbit.

Every owner who uses an assistant daily ends up typing the same paragraph. "I run a dog grooming salon in Reading, write in British English, keep it short, never offer discounts." Typed twenty times a week, that paragraph is an hour a month, and the chats where you forget it are the ones that come back American, long and full of exclamation marks. ChatGPT custom instructions fix that at the account level. OpenAI's own training material describes three layers: account settings for the stable context, project instructions for one client or job, and the prompt itself for the task in front of you. Most people only ever use the third.

Below: where the setting lives and what it can hold, the 15 examples by job, what to keep out for privacy and accuracy, the same feature in the other assistants, the data control to check, and how a Jobbit agent turns a standing instruction into work that runs on a schedule.

Where the setting lives and what it holds

In ChatGPT the setting sits under your profile, then Settings, then Personalization, where you will also find memory and the tone controls OpenAI added in December 2025 (warmth, enthusiasm and how much it uses headers and lists). The custom instructions box asks what the assistant should know about you and how it should respond. The historic limit was 1,500 characters a box; reports of OpenAI's July 2026 release notes say paid plans rose to 5,000, and the Free limit was not stated, so write for 1,500 and you are safe on every plan. Check the box in your own account rather than trusting a screenshot: OpenAI changes the wording of this page often.

Three things to know before you write one:

• It applies to new chats, not to Custom GPTs. OpenAI's help pages, as summarised in several guides, say a Custom GPT ignores your custom instructions and memory. Projects have their own instruction field that applies inside the project.
• It is not memory. Memory is what the model saves about you from conversations and updates itself. Custom instructions are what you wrote and only change when you edit them. The Sources icon on an answer shows which of the two shaped it.
• It is read, not obeyed. A standing instruction nudges every answer. For anything that must happen, say it again in the prompt.

The four-line structure

1. Business and reader. One sentence each. "A two-van electrical firm in Sheffield; customers are homeowners and small landlords."
2. Output defaults. Length, language, format. "British English, under 150 words unless asked, no bullet points in emails, tables for comparisons."
3. Never list. The three or four things that would embarrass you. "Never quote a price, never promise a date, never use the word 'reach out'."
4. A sample. Forty words of your own writing. OpenAI's Academy recommends pasting writing samples so the model mirrors your style, and it works better than any adjective.

15 custom instructions examples to copy

Each example fits in 1,500 characters with room to add your own sample paragraph.

For the owner who does everything

• Sole trader, all jobs. "I run a one-person bookkeeping business in Cardiff for sole traders and small limited companies. Reader is usually a client who is not financial. British English, plain words, short paragraphs, no jargon without a one-line explanation. Never give a figure for tax owed or a deadline without telling me to check it against HMRC. Never use 'reach out', 'leverage' or 'delighted'. Sign emails 'Sian'."
• Cafe owner. "I own a 30-cover cafe in Leeds. When I ask for customer-facing text, it is for a regular, warm and local, under 80 words, no emoji, no exclamation marks. When I ask for staff text, it is for part-time students, clear and kind. Never offer free food or refunds in any draft; I decide those. Prices only from what I paste."
• Tradesperson. "Two-person plumbing and heating firm in Kent, Gas Safe registered. Customers are homeowners. Quotes use labour at £65 an hour plus VAT and materials at cost plus 15% unless I say otherwise. Every quote has 30-day validity and our terms: 50% deposit, balance on completion. Never promise a start date. Keep everything under 200 words."
• Online shop. "Gift shop in York selling online and in store to women aged 35 to 60. Product copy is 50 words, British spelling, mentions material and where made, never 'perfect for' or 'must-have'. Customer service replies are apologetic once, then practical, and never argue about a refund under £30, which we just give."

For marketing and writing

• Brand voice. "All marketing copy is in our voice: direct, dry, no superlatives, no questions as headlines, sentences under 20 words, one idea per paragraph. We say 'customers', never 'clients' or 'users'. Here is a sample: [paste 40 words]."
• Social posts. "Posts are for Instagram and Google Business Profile. Instagram under 120 words with the hook in the first line and no hashtags unless I ask. Google posts under 60 words with one call to action. Always give me two options. No emoji."
• Email newsletters. "Monthly newsletter to 1,200 subscribers who are past customers. One story, one offer, one link. Subject lines under 45 characters, no 'newsletter' in the subject. Plain text feel, no banners. End with my name, not the business name."
• Blog drafts. "Blog posts are for small business owners new to the topic. Answer the question in the first paragraph, use H2 headings, cite a named source for every number and tell me where you are unsure. UK context, GBP. No em dashes anywhere."

For operations and admin

• Quotes and proposals. "When I paste job notes, turn them into a quote: a table of lines with quantity, unit price and total, VAT shown separately, then a 60-word covering paragraph and our terms. Ask me for anything missing rather than inventing it."
• Customer service. "Replies to complaints: acknowledge the specific problem in the first sentence, apologise once, say what we will do and by when, and give one way to reply. Never blame the customer or a supplier in writing. Under 120 words. Flag any message that mentions legal action, injury or a regulator so I handle it myself."
• Spreadsheets. "When I paste data, return the cleaned version as a table with the column names I used, then the formula or steps, then the result. Assume Google Sheets unless I say Excel. Point out any row that looks wrong before you use it."
• Meeting notes. "Turn my rough notes into: decisions, actions with an owner and a date, and open questions. Nothing else. If a date is missing, write 'date needed' rather than guessing."

For people, money and compliance

• Recruiting. "Job adverts for our small team: under 300 words, the real day described honestly, the salary range stated (I will give it), no 'rockstar' or 'fast-paced'. Shortlist notes stick to the criteria in the advert. Anything about protected characteristics, redundancies or dismissals, stop and tell me to get HR advice."
• Finance drafts. "Cash flow and budget drafts use only the figures I paste, in GBP, show the working, and mark every assumption with the word ASSUMPTION so I can find it. Never estimate tax, VAT or National Insurance figures; leave a placeholder and tell me to confirm with our accountant."
• Landlord. "I let two flats in Nottingham as an individual landlord. Letters to tenants are polite, factual and never mention eviction or legal action. Repairs are sorted into urgent, within a week and routine. Anything about possession, deposits or the Renters' Rights Act, draft nothing and tell me to speak to a letting solicitor."

Six things to leave out

• Passwords, API keys and account numbers. The instruction is stored with your account and read into every chat. It is not a safe.
• Client names and personal data. Keep clients out of the standing note; paste what is needed into the one chat that needs it, and delete the chat after if it was sensitive.
• Policy manuals. A 20-page terms document does not belong in a 1,500-character box. Put the three rules that matter and keep the manual in a Project file.
• Facts that change. Prices, opening hours, this month's offer. They will be wrong in six weeks and the model will use them confidently.
• Instructions for one job. "Write the Christmas email" is a prompt, not a standing instruction. Put it in the chat or in a Project.
• Contradictions. "Be concise" and "always explain your reasoning fully" cancel out. Pick one default and override it when you need to.

The same feature in Claude, Gemini, Copilot and Jobbit

Two things stand out. Gemini users have a deadline: Gems stop being editable on 17 November 2026 and convert to skills, so copy any Gem instruction you rely on into the new format. And the big consumer plans are personal products. Claude's consumer terms, read on 9 November 2026, say the Free, Pro and Max plans are not for commercial or business purposes, and Microsoft's Copilot terms say the free consumer Copilot is for personal use only. If the assistant is doing business work every day, the business or team tier is the one whose terms fit, and it is also the tier that is excluded from training by default.

The data setting to check

On personal ChatGPT accounts, the setting that lets your chats improve the model is under Settings and Data controls and is on by default, according to OpenAI's help pages as reported by several guides; Business and Enterprise plans are excluded by default. Claude has a Model Improvement toggle in Privacy settings and never uses incognito chats. Gemini uses activity to improve its services, including training, while Gemini Apps Activity is on. Mistral's web app has a toggle under Privacy. Whatever you put in a custom instruction is part of that data, which is the second reason to keep client names and account numbers out of it.

On Jobbit a Project's instructions, files and secrets stay in your workspace, the free plan is 100 credits a day with no card, Go is £7 a month for 2,000 credits and hosting on your own domain, and Plus at £15 a month is the plan most small businesses pick. Nothing you build is published unless you deploy it.

How an AI agent turns the instruction into work

• The instruction becomes a brief that runs. "Every Monday at 8 am, read the till export in this Project and draft the specials board and the rota" is a scheduled task, not a chat you remember to open.
• It reads the real files. Attach the price list once in the Project and every quote uses it, instead of the model guessing from a six-month-old instruction.
• It keeps secrets out of the prompt. Jobbit Projects hold secrets separately from instructions, so the booking-system key is never typed into a chat box.
• It builds the thing the instruction describes. The no-show policy in your instruction can become a booking page with deposits, built and hosted on your domain. Our first week with an AI agent guide walks through it day by day.
• It knows when to hand over. The landlord instruction says "draft nothing about possession". An agent on Jobbit can book a vetted letting specialist from the network for that part, with payment held in escrow.
• It compares honestly. ChatGPT, Claude, Gemini, Microsoft Copilot, Manus and Meta's Muse all answer better with a standing instruction. The gain from an agent is that the instruction stops being a note and starts being a job.

Read next

• 25 ChatGPT Tips and Tricks for 2026: Better Answers in Half the Time
• How to Write Prompts for AI Agents: 30 Examples That Get Results
• Which AI Should You Pay For in 2026? ChatGPT vs Claude vs Gemini Compared

Frequently asked questions

What should I put in ChatGPT custom instructions for a business?

Four things: what the business is and who it sells to, how answers should look (language, length, format), what the assistant must never do, and a short sample of your own writing. Keep it under 1,500 characters so it fits every plan, and put job-specific detail in a Project or the prompt instead.

Do custom instructions apply to every chat?

They apply to your ordinary chats and are read at the start of each one. Custom GPTs ignore them and use their own configuration, and Projects have their own instruction field that applies inside the project. OpenAI changes this page often, so check the behaviour in your account.

What is the difference between custom instructions and memory in ChatGPT?

Custom instructions are text you wrote and control. Memory is what ChatGPT saves about you from conversations and updates itself, and you can review or delete it under Personalization. The Sources icon on an answer shows which of them influenced it.

Does Claude or Gemini have custom instructions?

Yes. Claude has profile instructions under Settings and Your Claude, plus Project instructions, with up to five Projects on the free plan. Gemini's Gems hold instructions and files, become read-only on 17 November 2026 and convert to skills by 17 December 2026. Microsoft 365 Copilot builds agents with an instruction field of up to 8,000 characters.

Are my custom instructions used to train the model?

On personal ChatGPT plans the chats, including the instruction, can be used to improve the model unless you turn the Data controls setting off; Business and Enterprise are excluded by default, according to OpenAI's help pages as reported. Claude has a Model Improvement toggle. Keep passwords, client names and account numbers out of the instruction whatever the setting.

Can an AI agent use a standing instruction to do the work for me?

Yes. On Jobbit a Project holds the instruction, your files and any secrets, every chat in it inherits them, and the job can run on a schedule and build or host the result. The free plan is 100 credits a day with no card.