Writing & chat · guidance updated 4 Oct 2026
ChatGPT prompt guide
Default is GPT-5.5 Instant (concise, fewer hallucinations); Plus/Pro get GPT-5.6 Sol with a thinking-effort slider (Instant/Medium/High). GPT-6 Astra is limited rollout. Reasoning tiers want goals, not step-by-step micromanagement.
How to prompt ChatGPT
- Put the instruction first, then separate any pasted material with ### or triple quotes.
- State the goal and the audience in one plain sentence before any detail.
- Replace vague size words with numbers: '5 bullets', '150-200 words', '3 options'.
- Name the exact output shape (table columns, headings, JSON keys) and show a mini example if format matters.
- Say what to do rather than what not to do; frame restrictions as the desired behaviour.
- For style, describe it concretely: 'short paragraphs, main point first, no filler phrases like delve or leverage'.
- GPT-5.5 Instant trims answers; ask explicitly for depth, examples or alternatives when you want them.
- For hard analysis or planning, tell the user to pick Medium/High thinking and give the model the goal and success criteria rather than a scripted chain of steps.
- Phrase requests as direct instructions ('Write...', 'Compare...'), not 'can you...', so it does the work instead of offering to.
- If facts must be current, say 'search the web and cite sources' to trigger browsing.
- Include the constraints that matter (deadline, budget, region, tools) so it doesn't ask avoidable clarifying questions.
- End with what to do if information is missing: make a stated assumption or ask one question.
The shape of a good prompt
[Role/goal: who it's for and what outcome] [Task: direct imperative instruction] [Context: key facts, constraints, audience] ### [Input material, if any] ### [Output format: length, structure, tone] [Fallback: assume vs ask; cite sources if web needed]
Avoid
- Fuzzy length/tone words ('fairly short', 'make it good')
- Long lists of 'don't' rules instead of describing the target
- Scripting step-by-step reasoning for Thinking models
- Mixing pasted text and instructions without delimiters
- Stacking several unrelated tasks in one prompt
Example
Request help me write an email asking my landlord to fix the heating
Write a polite but firm email to my landlord asking them to repair the heating. Context: The heating in my flat has not worked for 5 days. I reported it by phone on Monday and have had no reply. It is getting cold and I work from home. Requirements: - 120-180 words, short paragraphs, main request in the first two sentences - Ask for a repair date within 3 working days and a reply by Friday - Courteous, factual tone; no threats - Include a clear subject line Use [square-bracket placeholders] for my name, address and the landlord's name.
