How to write better prompts for Claude: the colleague test and four fixes

For store owners, freelancers and marketers who use Claude and get answers that feel generic.

By the end you will have a test that tells you in ten seconds whether a prompt is clear, four fixes to apply when it is not, and one template you can reuse for product pages, WhatsApp replies and ad copy.

The advice below comes from Anthropic's own prompting best practices.

The idea in one line

Anthropic describes Claude as a brilliant but new employee who lacks context on your norms and workflows. The more precisely you explain what you want, the better the result.

The colleague test

Show your prompt to a colleague who knows nothing about your task and ask them to follow it. If they would be confused, Claude will be too.

Run it on this prompt:

Write a product description.

A colleague would ask: which product, for whom, how long, in which language, where will it appear? Claude has no way to ask, so it guesses, and you get a generic answer.

Fix 1: say the output and the limits

Be specific about the format and the constraints. Anthropic's example: "Create an analytics dashboard" gets better when you add what you want it to include and how far to go.

Before:

Write a product description for my posture corrector.

After:

Write a product description for a posture corrector sold with cash on delivery in Morocco.
Format: one headline of 8 words or fewer, 3 short benefit lines, one closing line about delivery and payment on receipt.
Language: simple French that a customer reads on a phone.
Do not use medical claims.

Fix 2: give the reason

Context and motivation help Claude aim at your real goal. Anthropic's example replaces "NEVER use ellipses" with the reason: the text will be read aloud by a text-to-speech engine that cannot pronounce them.

Add one sentence that starts with "This is for" or "This will be".

This will be pasted into my product page. Buyers decide in a few seconds and many are on mobile, so keep every line short.

Fix 3: show examples

Examples are one of the most reliable ways to steer format, tone and structure. Anthropic recommends 3 to 5 examples that are relevant, varied enough that Claude does not copy one pattern, and wrapped in tags so they are not confused with instructions.

<examples>
<example>Headline: Stand straight, feel the difference
Benefit: Light enough to wear under a shirt.</example>
<example>Headline: Your back will thank you
Benefit: Adjusts in seconds, no tools.</example>
</examples>
Write the new description in the same style.

Fix 4: structure long prompts with tags

When a prompt mixes instructions, context, examples and inputs, put each in its own tag. Anthropic suggests consistent, descriptive tag names such as instructions, context and input.

Reusable template

Copy this, replace the text in brackets, delete what you do not need.

You are a copywriter for a COD store in Morocco.

<context>
Product: [product and price in MAD]
Customer: [who buys it and what worries them]
Where this text appears: [product page, WhatsApp, ad]
Why it matters: [your real goal, for example fewer refused orders]
</context>

<instructions>
1. [first step]
2. [second step]
</instructions>

<format>[length, structure, language]</format>

<examples>
<example>[a good sample you already have]</example>
</examples>

Three before and after prompts for a COD store

1. WhatsApp reply. Before: "Reply to this customer." After: "Reply to this customer who asked if delivery is free. Two sentences, Darija in Latin letters, friendly, end by asking for the best time to deliver."
2. Ad hook. Before: "Give me hooks." After: "Give me 5 hooks for a 15 second video about [product]. Each hook under 10 words, start with a problem the buyer feels, no exaggerated promises."
3. Refund policy text. Before: "Write a return policy." After: "Write a return policy for a COD store. Context: customers sometimes refuse parcels at the door. Goal: calm, clear, 5 lines, no threats."

A five-point check before you press enter

1. Would a stranger know what to do?
2. Is the format written down?
3. Did you say why it matters?
4. Is there at least one example?
5. Are instructions, context and input separated?

My honest take

Most weak answers come from missing context, not from a weak model. Spend two extra minutes on the prompt and you save ten minutes of rewriting.