You want to control how Perplexity behaves inside a Space so it always answers in a specific tone, format, or knowledge area. A Space without a custom prompt uses the default assistant behavior, which may not match your project needs. This article shows you how to add a custom instruction prompt to a Perplexity Space. You will learn the exact steps, see what the prompt does, and avoid common mistakes that break the setup.
Key Takeaways: Custom Instruction Prompts in Perplexity Spaces
- Space Settings > Instructions: The only place to add a custom prompt that applies to every query inside that Space.
- Write clear, specific instructions: State exactly how you want answers formatted, what tone to use, and which knowledge sources to prioritize.
- Test with a sample query: Always send a test question after saving the prompt to verify the assistant follows your instructions correctly.
What a Custom Instruction Prompt Does in a Perplexity Space
A Perplexity Space is a dedicated workspace where you can ask questions about a specific topic or project. By default, the assistant inside a Space behaves like the main Perplexity search — it uses general knowledge and returns results from the web. A custom instruction prompt overrides this default behavior.
When you add a custom prompt, you tell the assistant exactly how to respond. You can set rules for answer length, writing style, source preference, or even the persona the assistant should adopt. For example, you can instruct it to always answer as a technical writer, to cite only peer-reviewed papers, or to summarize each answer in three bullet points.
The prompt is stored inside the Space and applies to every new conversation you start within that Space. Existing conversations are not affected unless you delete them and start fresh. The prompt does not carry over to other Spaces or to the main Perplexity search.
No special permissions are needed to add a prompt. Any user who can edit the Space can create or change the instructions. If you are using a shared Space, all members see the same prompt and the assistant responds to them using those instructions.
Steps to Add a Custom Instruction Prompt to a Perplexity Space
Follow these steps exactly. The interface may change slightly with updates, but the menu names remain the same.
- Open the Perplexity Space you want to edit
Go to your Perplexity dashboard. Click the Space name from the left sidebar or Spaces list. The Space opens with its conversation history and settings. - Click the Space settings gear icon
Look at the top-right corner of the Space view. Click the gear or three-dot menu icon. A dropdown or panel appears with options for the Space. - Select Edit Space or Space Settings
From the menu, choose Edit Space or Space Settings. The exact label depends on your account type. A settings page opens with fields for the Space name, description, and instructions. - Locate the Instructions field
Scroll down the settings page until you see a text area labeled Instructions or Custom Instructions. This is a large empty box where you type your prompt. There is no character limit shown, but keep your prompt under 1000 characters for best results. - Write your custom instruction prompt
Type your instructions in plain English. Be specific and direct. For example: “You are a senior data analyst. Answer every question with a table of key metrics first, then a short paragraph explaining the trends. Use only sources from the last 12 months.” Do not use markdown formatting inside the prompt — the assistant may misinterpret it. - Save the Space settings
Click the Save button at the bottom of the settings panel. Perplexity applies the new prompt to the Space immediately. A confirmation message appears at the top of the page. - Test the prompt with a sample query
Return to the Space conversation view. Type a question related to your Space topic. Check if the answer follows your instructions. If not, edit the prompt and save again.
After saving, the prompt is active for all new queries. Old conversations in the Space still show the previous assistant behavior. To see the prompt in action on old conversations, delete those conversations first or start a new one.
What a Well-Written Prompt Looks Like
A good prompt is clear, specific, and actionable. Here is an example that works well for a research Space:
“You are a research assistant specializing in climate science. Answer each question with a one-paragraph summary followed by three key findings. Cite at least two sources from scientific journals. If no journal source is available, state that clearly. Do not use sources older than 2020.”
Notice the prompt tells the assistant who it is, what format to use, how many sources to cite, and what to do when sources are missing. Avoid vague phrases like “be helpful” or “give good answers.” Those do not change the assistant behavior.
Common Mistakes When Adding Custom Prompts to a Space
The Assistant Ignores My Instructions After Saving
This usually happens when the prompt is too long or contains contradictory rules. Perplexity may truncate prompts over 1000 characters without warning. Keep your prompt under that limit. Also, avoid telling the assistant to do two opposite things. For example, do not say “always give short answers” and then “explain every detail.” Pick one instruction per behavior.
Another cause is testing the prompt on an old conversation. The prompt only applies to new conversations. Start a fresh query or clear the conversation history before testing.
The Prompt Works on Desktop but Not on Mobile
Perplexity mobile apps sync the same Space settings, including the custom prompt. If the prompt works on desktop but not on mobile, the app may be using a cached version. Force close the app and reopen it. If the issue persists, log out and log back in on the mobile device.
Also check that you are using the same Perplexity account on both devices. A second account with different Space settings will not show the prompt.
Other Members of a Shared Space Cannot See the Prompt
All members of a shared Space see the same assistant responses based on the prompt. However, they cannot view or edit the prompt text unless they have edit permissions. If you want others to know what the prompt says, paste it into the Space description or share it in a pinned message. The prompt itself is not visible in the conversation interface.
The Prompt Does Not Affect File Uploads or Images
Custom instruction prompts only influence text-based answers. If you upload a PDF or image and ask the assistant to analyze it, the prompt still applies to the text response. But the assistant may ignore format instructions when the answer requires a long analysis. You cannot force the assistant to summarize an image into a table if the image content does not support that format.
| Item | Without Custom Prompt | With Custom Prompt |
|---|---|---|
| Answer format | Assistant chooses format based on query | Follows your format rules (table, bullet list, paragraph) |
| Source preference | Uses general web search | Prioritizes your specified source types or dates |
| Tone and persona | Neutral assistant tone | Adopts the persona you define (analyst, writer, teacher) |
| Consistency across queries | Each query may produce different styles | All answers follow the same structure |
A custom prompt gives you control over the assistant behavior inside a Space. The key is writing a short, clear instruction and testing it immediately. If the assistant does not follow your rules, edit the prompt and save again. You can change the prompt anytime without losing the Space history.
Once your prompt is active, try combining it with the Space-specific knowledge sources feature. Upload documents or link web pages to the Space so the assistant uses both your instructions and your curated content. This combination produces the most accurate and consistent answers for any project.