Gareth MorgansProduct
Custom instructions don't scale to a team
ChatGPT custom instructions are one of the most useful settings you can change. They tell it who you are, how you like answers and what to avoid, so you stop repeating yourself in every chat.
They also belong to one person. On a team, that means the same house style gets typed into a dozen accounts, by hand, and each copy slowly becomes its own version.
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What custom instructions do
Custom instructions are standing guidance that ChatGPT considers in every response. According to OpenAI’s help article on custom instructions, they apply to all your chats, they are available on every plan, and they work on the web, desktop, iOS and Android.
On the web and desktop, you will find them under Settings, then Personalization. On iOS and Android, the setting is called Customize ChatGPT. In both cases, Enable customization must be switched on before your instructions take effect.
There is a length limit. Free and Go users can save up to 1,500 characters. Plus, Pro, Business, Enterprise and Education users can save up to 5,000. You can edit or delete them at any time.
What to put in them
Good custom instructions are specific and short enough to stay true. Four kinds of detail earn their place.
Who you are. Your role, your field and what you usually use ChatGPT for. “I run marketing for a B2B software company in the UK” gives far more to work with than “I work in marketing”.
How you want answers. Length, format and tone. For example: “Lead with the answer. Use short paragraphs. Only use bullet points for steps.”
Your house rules. Spelling, terms and phrases you never use. For example: “Use British English. Say ‘customers’, never ‘users’. Do not invent statistics.”
What to check first. Habits you want by default, such as asking a clarifying question when a request is ambiguous, or flagging anything it is unsure of.
Write them as plain instructions. Test them on a few real tasks, then cut anything ChatGPT ignores or overdoes.
Where they fall short for teams
Custom instructions live in one account. Nobody else sees them, and nobody else can update them for you.
So when a team agrees a house style, each person copies it into their own settings. Someone trims it to fit. Someone adds a rule of their own. Six months later, the brand voice has five versions and nobody knows which one is current. That is the same problem as prompts scattered across tools, one settings page at a time.
ChatGPT does offer shared options. Projects hold their own instructions and files, and inside a project those instructions take the place of your personal ones. Projects can now be shared with teammates on Free, Plus, Business and Enterprise plans alike. GPTs were the other route, but OpenAI plans to retire custom GPTs and recommends moving those workflows to plugins. Retirement is planned for 11 December 2026 in affected Enterprise workspaces, with other plans expected to follow the same timeline. Both live inside ChatGPT. Neither reaches the other tools your team uses, such as Claude, Cursor or Copilot, where the same rules need to apply.
Keep one source of truth
The fix is to decide where the real copy lives. Keep your house style, your context and your rules as named prompts in one shared place, and treat every custom instructions box as a copy of that source.
That is what Joyst is for. Your team keeps its approved prompts in one library and reuses them across the tools it already uses. Permissions separate the people who can view a prompt from the people who can manage it, so the house style stays consistent while everyone can use it. A shared team library also beats a pinned document, because each entry has a current version and a history.
Joyst does not write into ChatGPT settings. When the source changes, each person updates their own copy from it. The difference is that everyone copies from the same page.
Version and own them
Instructions change. A new product name, a new rule about claims or a better phrasing all need to reach everyone, and you need to know what changed and when.
Give each shared instruction an owner, keep its history and publish changes deliberately. If a new wording makes answers worse, you can go back to the last good version. Our guide to how prompt versioning works covers drafts, publishing and rollback in more detail.
For coding tools, Joyst goes a step further. Skills come as downloadable versions for Claude Code, Cursor, Codex CLI, Copilot and Windsurf, and each tool pulls them through the Joyst MCP server.
FAQ
Where are custom instructions in ChatGPT?
On the web and desktop, open Settings and select Personalization. On iOS and Android, open Settings and select Customize ChatGPT. Make sure Enable customization is switched on.
How long can custom instructions be?
Up to 1,500 characters on Free and Go, and up to 5,000 characters on Plus, Pro, Business, Enterprise and Education, according to OpenAI’s help centre.
Can I share custom instructions with my team?
Not directly. They belong to one account. A shared project can carry instructions for a group inside ChatGPT, and it does not use anyone’s personal custom instructions.
Does Joyst update ChatGPT custom instructions for us?
No. Joyst holds the approved, versioned source your team copies from and reuses across tools. It does not connect to ChatGPT accounts or change their settings.