Custom Prompts Guide

The four parts

• Role: who the model is answering as.
• Task: exactly what you want done, in one sentence.
• Context: the level, the subject, the syllabus, the audience.
• Format: how the answer should be laid out, and how long it should be.

Why format is the one people forget

A model that has not been told what shape the output should take will choose one — and it will choose a different one tomorrow. Naming the format is what turns a good answer into a repeatable one, which is the whole point of saving a prompt.

Step by step

1. Start from something you have already asked for more than once.
2. Write all four parts out in full, including the ones that feel obvious to you.
3. Run it, then fix the prompt rather than the answer, and note what you changed.
4. Run it once more on a different input, to check it is not tuned to a single case.
5. Save it under a name that says what it produces, not which subject it came from.
6. Set the temperature with it: low when the same input should give the same output.

Leave gaps to fill in

Write the parts that change as visible placeholders — [subject], [grade level], [chapter] — so the prompt is reusable and it is obvious at a glance what has to be swapped before it is run. A placeholder you can see is a placeholder you will not forget.

Study guide creator

Role: study guide creator. Task: build a revision guide for [subject], [chapter]. Context: for a [grade level] learner following [syllabus]. Format: key concepts, one worked example each, then eight practice questions with the answers at the end.

Step-by-step problem solver

Role: step-by-step problem solver. Task: solve the [problem type] problem I give you. Context: show the level of working expected at [grade level]. Format: numbered steps, the reason for each step, then the answer and one alternative method.

Answer sheet marker

Role: examiner. Task: mark the attached handwritten answer against the key below. Context: [subject] at [grade level], mark scheme as given. Format: marks per part with the reason for each, then two lines of feedback written for the student to read.

Image explainer

Role: subject teacher. Task: explain the attached diagram to someone seeing it for the first time. Context: [subject] at [grade level]. Format: what it shows overall, then each labelled part in turn, in no more than 200 words.

Organising

• Group prompts by what they produce — explanations, question sets, marking, image work.
• Tag by subject, so the maths ones are findable without reading every prompt.
• Name them for the output: "Chapter revision sheet" beats "Prompt 3".
• Retire prompts a newer one has replaced, instead of leaving both in the list.

Sharing across a class or department

A prompt is only text, so it travels. Hand the wording to a colleague and they get exactly your output format. Across a department this is what makes marking consistent between teachers, because everyone is asking for the same thing in the same words rather than each improvising.

Keeping versions

• Keep the working version before you edit a prompt that already does its job.
• Note what a change was meant to fix, so a later reader knows why the wording is odd.
• Date the version you standardised on, if a whole department is using it.

The short list

• Change one thing per attempt, or you learn nothing from the result.
• Be specific about the outcome and about who will read it.
• Show an example of the format you want when describing it is harder than showing it.
• Break a large request into smaller ones the model can actually finish.
• Say what to leave out as well as what to include.
• Lower the temperature when the same question should give the same answer twice.