Anthropic suggests replacing "do not use markdown in your response" with "your response should be composed of smoothly flowing prose paragraphs". Why is the second form stronger?

Easyprompt-engineeringfundamentalsconstraints

Last reviewed 10 Aug 2026

It states a positive target, where a prohibition rules out only one wrong shapeCorrect answer
It states the requirement twice in different words, which reinforces it
It is phrased politely, and courteous instructions are complied with more often
It avoids the word "not", which models are known to skip when reading an instruction

Show answer & explanation

Correct answer: A. It states a positive target, where a prohibition rules out only one wrong shape

Explanation

The principle — A prohibition narrows the space of answers by one. A specification points at the answer you want.

Why the key is correct — Anthropic's guidance on controlling output format is to tell a model what to do instead of what not to do, giving this exact pair as its illustration. "No markdown" is satisfied by a wall of unbroken text, by a numbered outline in plain characters, and by many other things you did not want. "Smoothly flowing prose paragraphs" is satisfied by one of them.

Why the others are wrong — Politeness is not a lever. Negations are read rather than skipped. And the rewrite states one requirement once rather than repeating it.

Remember this — Every prohibition has infinitely many compliant wrong answers. Describe the target instead.

Sources — Anthropic, Prompting best practices.

Sources

Primary sourcePrompting best practices — Anthropic · accessed 9 Aug 2026
“Tell Claude what to do instead of what not to do”

Practise 10 questions on this topic

Take Prompt Engineering Fundamentals — Timed Test 1 (10 questions) — scored instantly, explanation for every question, no login.

Start the test

Anthropic suggests replacing "do not use markdown in your response" with "your response should be composed of smoothly flowing prose paragraphs". Why is the second form stronger?

Easyprompt-engineeringfundamentalsconstraints

Last reviewed 10 Aug 2026

It states a positive target, where a prohibition rules out only one wrong shapeCorrect answer
It states the requirement twice in different words, which reinforces it
It is phrased politely, and courteous instructions are complied with more often
It avoids the word "not", which models are known to skip when reading an instruction

Show answer & explanation

Correct answer: A. It states a positive target, where a prohibition rules out only one wrong shape

Explanation

The principle — A prohibition narrows the space of answers by one. A specification points at the answer you want.

Why the others are wrong — Politeness is not a lever. Negations are read rather than skipped. And the rewrite states one requirement once rather than repeating it.

Remember this — Every prohibition has infinitely many compliant wrong answers. Describe the target instead.

Sources — Anthropic, Prompting best practices.

Sources

Primary sourcePrompting best practices — Anthropic · accessed 9 Aug 2026
“Tell Claude what to do instead of what not to do”

Practise 10 questions on this topic

Take Prompt Engineering Fundamentals — Timed Test 1 (10 questions) — scored instantly, explanation for every question, no login.

Start the test

Anthropic suggests replacing "do not use markdown in your response" with "your response should be composed of smoothly flowing prose paragraphs". Why is the second form stronger?

Related questions

Anthropic suggests replacing "do not use markdown in your response" with "your response should be composed of smoothly flowing prose paragraphs". Why is the second form stronger?

Related questions