How to use a system prompt in Gemini
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Gemini has two places in the app for saved instructions, Gems and skills, and Google is replacing Gems with skills. Google AI Studio and the Gemini API take system instructions directly. The prompts on this site are between about 9,000 and 25,500 characters long, with most around 14,000. For how they are structured and what the bracketed slot at the end is for, see How to use the prompts on this site.
Gems and the move to skills
Google's help centre gives these dates for when Gems stop being available:
| Account type | Gems removed |
|---|---|
| Personal Google accounts | November 2026 |
| Workspace business, enterprise and non-profit accounts | March 2027 |
| Workspace education accounts | June 2027 |
Google says existing Gems, with supported files, will be recreated as skills automatically when Gems go away. You can also recreate a Gem as a skill yourself before then.
Creating a Gem
While Gems are still available on your account:
- On a computer, go to gemini.google.com.
- Click Open Sidebar, then Gems. If you have never made a Gem, first click Settings and help, then Gems.
- Click New Gem.
- Enter a name, and paste the prompt as the instructions. Delete the closing label and bracketed slot, such as
[REQUEST], first. - Optionally, under Knowledge, click Add files, then Upload files for a file from your device or Add from Drive.
- Use the preview box on the right to try a request, then click Save.
The editor has a Use Gemini to re-write instructions option. It has Gemini generate new instructions from what you have entered, so the result is no longer the prompt as written.
Google's Gems article does not state a character limit for the instructions field. For knowledge files it points to Gemini's general upload limits, which allow up to 10 files (subject to availability) and up to 100 MB per file other than video. To create and use Gems with a personal Google Account you must be 13 or over, or the applicable age in your country.
Creating a skill
Skills are reusable instructions that Gemini applies when it judges them relevant to your prompt, or when you select one. Google's requirements are:
- 18 or over, signed in with a personal Google Account. Work and school accounts do not have skills yet.
- Keep Activity turned on.
- The Gemini web app, the Gemini app on Mac, or the Gemini mobile app.
To create a skill from a prompt on this site:
- Go to gemini.google.com.
- On the sidebar, click Settings, then Skills.
- Click Create manually.
- Enter a name and a description of what the skill does, and paste the prompt into the instructions, without the closing slot.
- Click Create.
To use it, type / in a chat and select the skill. Gemini can also apply a skill on its own when your prompt matches its description, so the description affects when the prompt is used. You can deactivate a skill from the Skills page to stop automatic use.
You can also upload a skill as a SKILL.md file, or a folder or .zip file containing one, using Upload on the Skills page. Uploaded files must be plain-text based (such as .txt or .md, plus PDF and images), the skill name must be lowercase with hyphens, and the total size must not exceed 100 MB. A prompt from this site is roughly 9 to 26 KB of text.
Google's skills article does not state a character limit for the instructions field. You can have up to 100 skills active at a time. Google says skills do not yet work with some features, including Canvas and Deep Research.
Pasting into a chat
This works with any Google account that can use Gemini:
- On the prompt page, select Copy prompt.
- Start a new chat at gemini.google.com and paste.
- Replace the bracketed slot at the end with your request and any material, then send.
The instructions apply for that chat. A new chat starts without them.
Google AI Studio
- Open Google AI Studio. The Playground opens with a new chat prompt.
- Click Run settings in the top-right corner to expand the panel.
- Paste the prompt, without the closing slot, into the System Instructions field.
- Type your request in the chat box.
System instructions can be changed after the chat has started.
The Gemini API
The Gemini API takes the prompt in a system_instruction parameter, separate from the user's input. Google's documentation describes it as a way to "guide the behavior of Gemini models". Pass the request itself as the input, and include the system instruction with each request.
Sources
Menu names and labels in Gemini change from time to time. These are the official pages used for this guide, checked on 2026-10-03: