What makes a good prompt for Claude?
Claude is the AI assistant developed by the company Anthropic. Like ChatGPT, it's built on a large language model, but it has its own personality — and a few habits that, once you know them, let you get the best out of it. If you've read our article on good prompts for ChatGPT, you'll find the same basic principles here, rounded out with what makes Claude distinctive.
Claude's personality
Claude is known for being careful, nuanced and comfortable with long texts. It likes clear, structured instructions and willingly follows detailed requests. Where you might think a long instruction would "confuse" it, the opposite is often true: the more explicit you are, the better the result. Claude prefers being told precisely what you expect rather than having to guess.
It's also an excellent partner for working on a document: having it proofread a text, summarise a long email, compare two versions, rephrase a letter.
The basics, still valid
You'll find the same ingredients of a good prompt covered earlier: be specific, give context, assign a role, state the format you want and, if needed, provide an example. Now let's look at what Claude particularly appreciates.
What Claude likes: separating the instruction from the content
This is the most useful trick, and the simplest. When your request mixes an instruction ("fix the typos") with content to process (the text to correct), Claude does much better if you clearly separate the two.
A very effective way: surround the content with tags or visible markers. You don't need any computing knowledge — just invent a label:
Fix the spelling mistakes in the text below, without changing its meaning.
<text> I am writing to inform you that the meeting as been postpone to tuesday. </text>
These tags (<text> … </text>) clearly tell Claude: "this is the material to process, not an instruction". The result is more reliable, especially when the text is long or itself contains questions.
What Claude likes: being told the "why"
Claude responds better when it understands the intent behind the request. Rather than "shorten this text", try "shorten this text because it has to fit in a text message read quickly by a busy client". The context helps it make the right trade-offs — here, keeping the essentials and cutting the rest.
What Claude likes: being allowed to think
For requests that involve reasoning (a calculation, a comparison, a justified choice), explicitly invite it to work step by step: "Think step by step before concluding." Claude then lays out its reasoning, which improves the quality of the answer — and lets you spot any mistake.
A before / after example
Weak prompt:
Summarise this. [a long email pasted right after, with no separation]
Result: Claude may confuse a question contained in the email with an instruction, or summarise it inaccurately.
Effective prompt:
You're my assistant. Summarise the email below in 3 clear points, so I can tell in 10 seconds what's expected of me. Keep a neutral tone.
<email> [paste the full email here] </email>
Result: a clean, faithful summary that clearly distinguishes the instruction from the content and answers the exact need.
What about long documents?
This is one of Claude's strengths: it can keep in view large amounts of text. You can paste a long report, a contract or several emails and ask it for a synthesis, a list of actions or the points of disagreement. Just remember to: place the document between tags, then ask your question clearly after the document.
Good habits
- Be explicit rather than allusive. Claude prefers a complete instruction to a guessing game.
- Separate instruction and content with simple markers.
- Give the intent. Saying what the answer will be used for improves relevance.
- Verify what matters. Like any AI, Claude can be wrong; for a fact or a figure, cross-check.
In short
Talking to Claude well comes down to a few habits: be explicit and structured, clearly separate what it should do from what it should process (tags work wonders), explain why you're asking, and let it reason step by step when that's useful. With its strength on long texts, it becomes a valuable partner for everything involving writing and document analysis.
In the final article of the series, we turn to LeChat, the assistant from the French company Mistral — with a particular advantage for English and multilingual users alike.