The 4 G's: a prompt formula that actually works.
Goal, Gist, Guardrails, Grill me. If your prompts keep landing flat, it's almost never the AI. It's the brief. Here's the formula I use every day.
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Most prompts are too short. You give Claude three words and expect mind-reading. The 4 G's fix it: Goal (what you want made), Gist (the background), Guardrails (your no-gos), and Grill me (tell it to ask questions first). You don't need fancy prompt engineering. You need a proper brief, and this is the shape of one.
Why Claude "misses".
Nine times out of ten it isn't the AI. You gave it "write me an Instagram caption" and expected it to read your mind. It can't read your mind, but it can read a brief. The 4 G's are just the four things every good brief contains, in an order that's easy to remember. Once you've used it a few times, you'll do it without thinking.
G is for Goal.
Say exactly what you want made. Not "help with my launch". Try "write me a five-email launch sequence for my new course". The more specific the goal, the less Claude has to guess, and guessing is where generic comes from. A vague goal can only ever produce a vague result.
G is for Gist.
The background you'd give a new hire. Who you are, who it's for, what you sell, what's going on right now. This is the part most people skip, and it's exactly where the magic lives. Claude can't know your world unless you hand it over. Two or three sentences of real context lifts the whole answer.
G is for Guardrails.
The bit everyone forgets. What should it avoid? "No corporate jargon. Don't mention price. Keep it under 150 words. No exclamation marks." Your no-gos shape the answer as much as your goal does. Telling Claude what not to do is often faster than fixing what it did.
G is for Grill me.
The cheat code. End your prompt with "ask me questions before you start". Now Claude tells you what it's missing instead of guessing and getting it wrong. This one line turns a one-shot gamble into a quick back-and-forth that lands far closer to what you actually wanted. If you only remember one G, remember this one.
Put it together.
Goal, then Gist, then Guardrails, then Grill me. Here's the whole formula as a fill-in-the-blank template. Save it, and drop your details into the blanks whenever you sit down to write something with Claude.
Goal: I want you to [exactly what you want made, be specific].
Gist: Here's the background. I'm [who you are] and I help [who you serve]. This is for [audience or context], and what's going on is [the situation].
Guardrails: Avoid [your no-gos, e.g. jargon, hype, anything over X words]. The tone should be [your tone].
Grill me: Before you start, ask me any questions you need to do this really well. Wait for my answers first.
Before and after.
Before: "Write me an Instagram caption." You get something generic that sounds like everyone else online. After: goal, gist, guardrails, and "ask me first". Now it sounds like you, for your audience, with your rules, and it asked what it needed before writing a word. Same tool. Completely different result. The only thing that changed was the brief.
You don't need all four G's for tiny tasks. A quick rewrite doesn't need a full brief. But the moment the output matters, content, emails, anything with your name on it, run the four. The thirty seconds it takes to brief properly saves you the ten minutes you'd spend dragging a generic answer back to something usable.
One last thing.
Prompt engineering sounds like a skill you have to study. It isn't. It's briefing, the same thing you already do when you hand work to a person. Goal, gist, guardrails, grill me. Four things, in that order.
If your prompts keep landing flat, it was never the AI. It was the brief. Now you have the shape of a good one.