# How to Master Claude Opus 5.5 Prompt Engineering From Scratch

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How to Master Claude Opus 5.5 Prompt Engineering From Scratch

A practical guide to writing clearer prompts, saving useful instructions and checking the answers you get

ChatGPT for All

Oct 3

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Claude writes a friendly reply to a customer. The tone is right. The message is short. Then you notice a promise that was never in your refund policy.

That is a useful place to start learning prompt engineering.

A prompt needs to explain the job, supply the information and define what a good answer must contain. After Claude responds, you still need to check it against the source.

In this guide, you will practise with one fictional shop. You will draft a customer reply, improve the instructions, catch a planted mistake and test the result on eight cases. Then you will save the instructions for your next conversation.

The main walkthrough happens in Claude in your browser. You do not need to write code. An optional Python section shows how the same instructions become an API system prompt.

Below are the complete sample files, copyable prompts, expected results and a checklist for deciding whether your prompt is ready to reuse...

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