System Prompt Examples: 5 Patterns + a Template

The 2 free places to read real ones

The 5 patterns all three use

We read Claude's (official, Claude Opus 5.5), Cursor's and Lovable's (collected) side by side. Every one of them does these five things.

1. Who you are. Lovable: "You are Lovable, an AI editor that creates and modifies web applications." Cursor: "You are an AI coding assistant… You operate in Cursor."
2. What you never do. Claude: "Claude never curses unless the person asks or curses a lot themselves." Cursor: "NEVER refer to tool names when speaking to the USER." Lovable: "Never implement a feature to switch between light and dark mode."
3. How to use tools. Cursor: "use your tools to read files and gather the relevant information: do NOT guess or make up an answer." Lovable: "always invoke all relevant tools simultaneously." Claude: when it isn't sure something it remembers is right, it "says so and suggests enabling web search."
4. How to format. Lovable: "keep your explanations super short and concise. Minimize emoji use." Claude: "avoids over-formatting with bold emphasis, headers, lists, and bullet points."
5. When to stop and ask. Cursor: on the third failed attempt to fix the same errors, "stop and ask the user what to do next." Claude: when it asks a question, "it avoids more than one per response." Lovable: "If unsure about scope, ask for clarification rather than guessing."

Copy the structure. Their words are about their product. Yours should be about your business.

Ned's fill-in system prompt template

Fill the brackets, delete the examples, and keep it short. Five clear lines beat five pages.

You are [who it is], helping [who you help] with [the job].

Never:
- [the thing that would hurt you, e.g. promise a refund or a delivery date]
- [the thing you hate, e.g. use jargon]

Tools: when [situation], check [the file, the price list, the web] first.
If you can't check something, say so. Don't guess.

Format: answer in [length, e.g. under 5 sentences], in [style, e.g. plain words, no headers], with [extras, e.g. minimal emoji].

Stop and ask: if [what's often missing, e.g. the order number], ask me one question before you start.

A filled-in example (a small bakery that answers customer emails):

You are the email helper for Rosa's Bakery, helping Rosa answer customer emails.

Never:
- promise a delivery time or a refund. Rosa decides those.
- invent a price. Use only the price list in the project files.

Tools: when someone asks about a cake or a price, check the price list file first.
If it isn't there, say "I'll check with Rosa." Don't guess.

Format: under 5 sentences, warm and plain, no bullet points, one emoji at most.

Stop and ask: if the email doesn't say the date or the number of people, ask me one question before you write the reply.

Where to paste it

If it still ignores you

1. It still does the thing you banned. Move that rule to the top and make it one plain sentence that starts with Never. Long paragraphs bury rules.
2. It guesses instead of checking. Name the exact file or source to check, and add "If you can't find it, say so."
3. Answers are too long. Give a number: "under 5 sentences" works better than "be concise".
4. It asks too many questions. Say "ask one question at most, then do your best with what you have."
5. It ignores the instructions completely. Make sure you're chatting inside the project (or the Gem), not in a new normal chat.