The same prompt gives different results in ChatGPT, Claude, and Gemini because each model was trained and fine-tuned with different instincts baked in. It’s not randomness or a bug — it’s three different systems with three different “personalities”, and a prompt tuned for one isn’t automatically ideal for another. Once you see the pattern, you can steer each one instead of being surprised by it.
Why they diverge
Each was built with a different philosophy. ChatGPT is optimized for instruction-following and structure. Claude is tuned for careful, nuanced reasoning and takes instructions literally. Gemini is built on Google’s knowledge infrastructure and leans toward factual, direct answers. Those aren’t marketing differences — they show up in the actual text you get back.
The practical upshot: what makes ChatGPT give a punchy, direct answer can make Claude go cautious and hedgy. What makes Gemini nail a research-heavy task can flop on ChatGPT because it wants instructions structured differently. Same words, different wiring.
How to adjust one prompt for each
You don’t need three totally separate prompts — you need to shift the emphasis. Here’s the short version of what each model rewards.
| Model | What it rewards | Adjust your prompt by… |
|---|---|---|
| ChatGPT | Direct instructions, structure, examples | Being blunt; adding one or two few-shot examples |
| Claude | Context, literal instructions, reasoning | Explaining why; using tags for long prompts |
| Gemini | Short, direct intent; clear role + format | Cutting filler; stating persona and format upfront |
A concrete example. Asking for a product description: on ChatGPT, give it two examples of the tone you want and a blunt instruction. On Claude, explain that it’s for a skeptical technical buyer who hates hype, and wrap your notes in tags. On Gemini, keep it to a crisp “You are a copywriter. Write a 50-word product description. Plain, no buzzwords.” Same goal, three tunings.
What stays the same everywhere
Under the differences, the fundamentals don’t move: every model does better when you state the outcome you want, the context it can’t see, and the format of the answer. The models disagree on style; they agree on substance. Miss the substance and all three give you something mediocre.
That’s the part worth automating. BeforePrompt runs inside all four major tools — ChatGPT, Claude, Gemini, and Copilot — and checks for the missing outcome, context, or format before you send, so the shared fundamentals are covered no matter which model you’re talking to that day.