Free tool

AI Prompt Generator & Optimizer

Generate professional prompts for ChatGPT, Claude, Gemini, and Mistral. Built for European SMB teams.

Powered by Mistral AI — EU-hostedNo account, no trackingWorks for ChatGPT, Claude, Gemini, Copilot

What makes a great AI prompt?

Research on prompt engineering consistently identifies the same five elements. Our generator assembles them for you — but understanding why each matters helps you refine outputs faster.

Role

Telling the AI who it is anchors its behaviour. "You are a senior data analyst" produces more precise output than a blank-role prompt. The AI selects relevant vocabulary, priorities and reasoning patterns.

Task

The task is what you actually want done. Be specific: include the deliverable, the scope and any success criteria. "Summarise" is weak; "Write a 3-bullet executive summary of the attached report, focusing on risk" is strong.

Context

Context removes ambiguity. Tell the AI who your company is, what industry you operate in, what the reader already knows, or what constraints apply. Without context, the model fills in blanks from generic training data.

Format

Specifying the output format — bullet list, table, JSON, executive report — prevents the AI from defaulting to flowing prose when you need something structured, or vice versa.

Tone

Tone shapes every word choice. "Professional" and "direct" produce very different outputs for the same task. Matching tone to your audience (client email vs. internal Slack) saves post-processing time.

Constraints

Word count, topics to avoid, required inclusions — constraints are the fastest lever for output quality. "Under 200 words" forces concision. "Do not mention competitors" protects your brand.

AI Prompts for Marketing Teams

Marketing teams use AI daily for content, campaigns and analysis. Structured prompts make the difference between generic output and copy you can ship.

Email marketing prompts

Effective prompts for subject lines, welcome emails, re-engagement campaigns and promotional sequences. Use these structured templates to get past generic AI output and into copy that converts.

Promotional email

You are an experienced email marketer.
Write a promotional email for [PRODUCT/SERVICE] targeting [AUDIENCE].
Context: [CAMPAIGN_CONTEXT].
Format: subject line + preheader + body (max 150 words) + CTA button text.
Tone: friendly and direct.

Subject line variations

You are a conversion copywriter.
Write 5 subject line variations for a re-engagement campaign.
Product: [PRODUCT]. Reason for re-engagement: [REASON].
Format: 5 subject lines, max 50 chars each, with A/B testing notes.
Tone: personal, curious.

Welcome email

You are an email strategist.
Write a welcome email for new newsletter subscribers about [TOPIC].
Format: short intro + 3 bullet points covering what they can expect + closing CTA.
Tone: warm and professional.

Social media content prompts

LinkedIn posts, content calendars and thought leadership for B2B audiences. These prompts help you write content that stops the scroll without sounding like a corporate brochure.

LinkedIn B2B post

You are a B2B LinkedIn content specialist.
Write a LinkedIn post about [TOPIC] for a [JOB_TITLE] at an SMB company.
Format: hook (first 2 lines), body (max 150 words), 3-5 relevant hashtags.
Tone: professional but personal, no corporate jargon.

Content calendar

You are a social media manager.
Build a one-week content calendar for [BUSINESS_TYPE] on [PLATFORM].
Theme of the week: [THEME].
Format: table with day, content type, hook, call-to-action.
Tone: aligned with audience.

LinkedIn carousel

You are a copywriter specialised in thought leadership.
Write a LinkedIn carousel post (8 slides) about [TOPIC].
Slide 1: striking statement. Slides 2-7: one insight per slide. Slide 8: CTA.
Tone: direct, opinionated, fact-based.

Marketing strategy prompts

Go-to-market plans, competitor analyses and positioning documents. Use these prompts when you need strategic thinking, not just copy.

Go-to-market summary

You are a senior marketing strategist.
Write a go-to-market strategy summary for [PRODUCT/SERVICE] aimed at [TARGET_MARKET].
Format: audience → value proposition → channels → KPIs → first 90 days.
Tone: strategic, decision-ready.

Competitor analysis

You are a market analyst.
Analyse the marketing position of [BRAND/PRODUCT] versus [COMPETITOR].
Format: SWOT table + 3 concrete recommendations.
Tone: objective, analytical.

SEO and blog prompts

Outline blog posts, write meta descriptions and structure pillar content. Combine these prompts with your keyword research for content that ranks.

Blog post outline

You are an SEO content strategist.
Write a blog outline for the keyword [KEYWORD], targeting [AUDIENCE].
Format: H1 + meta description (max 160 chars) + 5-7 H2 sections with bullet points + FAQ section (3 questions).
Tone: helpful, expert, EEAT-aligned.

AI Prompts for Sales Teams

Sales teams save hours per week with structured AI prompts for outreach, follow-up and call preparation. The right prompt is the difference between a personal email and a generic blast.

Cold outreach prompts

Personal, non-pushy opening emails and LinkedIn InMails. Use these prompts to write outreach that feels human, not templated.

Cold email

You are an experienced B2B sales development representative.
Write a cold outreach email for [PRODUCT/SERVICE] targeting [JOB_TITLE] at [COMPANY_TYPE].
Context: [TRIGGER_EVENT_OR_REASON].
Format: subject line + email (max 100 words) + PS line.
Tone: personal, concrete, not pushy.

LinkedIn InMail

You are a sales copywriter.
Write a LinkedIn InMail for [GOAL], targeting [PERSONA].
Format: opening line (personal), core (1 concrete benefit), CTA (low-friction).
Max: 300 characters.

Follow-up prompts

Concrete follow-up emails after demos, calls and quotes. Avoid the generic “just checking in” trap.

Post-meeting follow-up

You are an account manager.
Write a follow-up email after a sales meeting with [COMPANY] about [TOPIC].
Context: discussed points were [POINTS]. Next step is [ACTION].
Format: thanks + summary in bullets + next step + CTA.
Tone: business-like, concrete.

Discovery call preparation prompts

Walk into discovery calls with the right questions. These prompts generate question banks tailored to your prospect and product.

Discovery question bank

You are a senior sales consultant.
Generate 10 discovery questions for a sales call with [PROSPECT_TYPE] about [PRODUCT].
Format: 5 problem-discovery questions + 5 budget/timeline questions.
Tone: open-ended, not leading.

Objection handling prompts

Calm, confident responses to classic sales objections. Use these to prepare responses before they happen — not in the moment.

Objection response

You are a senior sales consultant.
The prospect says: "[OBJECTION]".
Write a response that acknowledges the objection, reframes it, and redirects to value.
Format: acknowledgement (1 sentence) + reframe (2-3 sentences) + clarifying question.
Tone: calm, confident, not defensive.

AI Prompts for HR Professionals

HR professionals use AI for job descriptions, interview questions and onboarding documents. The right prompt determines whether the output is usable or generic boilerplate.

Job description prompts

Inclusive, concrete job postings without buzzwords. Use these prompts to write listings that attract the right candidates and filter out the wrong ones.

You are an experienced HR recruiter.
Write a job description for the role of [JOB_TITLE] at [COMPANY_TYPE].
Context: team of [SIZE], [PARTTIME/FULLTIME], location [LOCATION].
Format: role overview + what we offer + ideal profile + application instructions.
Tone: inclusive, concrete, no buzzwords.

Interview question prompts

Behavioural and situational questions tailored to the role. These prompts help you assess competencies, not just charisma.

You are an HR business partner.
Generate 10 interview questions for the role of [JOB_TITLE].
Focus areas: [COMPETENCIES_OR_SKILLS].
Format: 5 behavioural questions (STAR method) + 5 situational questions.
Tone: open, non-leading.

Onboarding prompts

Welcome documents, week-1 plans and 30-60-90 day frameworks. Get new hires productive faster.

You are an HR onboarding specialist.
Build a 30-60-90 day plan for a new [JOB_TITLE] joining [TEAM].
Format: 3 phases, each with: goals + key deliverables + check-in questions.
Tone: clear, structured, encouraging.

Performance review prompts

Constructive, honest performance review notes that motivate without sugar-coating.

You are a manager preparing for a performance review.
Write notes for a review meeting with [ROLE].
Context: strong points are [POINTS], development areas are [POINTS].
Format: opening + retrospective + development priorities + next-year goals + close.
Tone: constructive, honest, motivating.

AI Prompts for Small Business

SMB owners and freelancers use AI for client communication, quotes and daily operations. No big marketing team, but professional output every time.

Client communication prompts

Empathetic complaint responses and confident quote cover letters. These prompts help small businesses sound like teams of ten.

Complaint response

You are a professional customer service representative.
Write a response to a complaint from [CUSTOMER] about [PROBLEM].
Context: [SITUATION].
Format: acknowledgement + explanation + solution + close.
Tone: empathetic, professional, solution-focused.

Quote cover letter

You are a small business owner.
Write a quote cover letter for [SERVICE/PRODUCT] to [CLIENT_TYPE].
Amount: [AMOUNT]. Validity: [PERIOD].
Format: personal opening + summary of approach + price + next step.
Tone: confident, personal, professional.

Operational efficiency prompts

Process analysis and improvement recommendations. Use these prompts to find inefficiencies before they cost you a customer.

You are a business consultant.
Analyse the following work process and identify three improvement areas: [PROCESS_DESCRIPTION].
Format: process overview + 3 bottlenecks + concrete recommendations per bottleneck.
Tone: practical, direct.

AI Prompts for Customer Service

Standard response templates, complaint handling and escalation management. Build a customer service voice that scales without losing the human touch.

Standard response templates

You are a customer service specialist.
Write 5 standard email responses for the most common questions about [PRODUCT/SERVICE].
Questions: delivery, returns, technical issue, billing, account.
Format: per response: subject + body (max 100 words).
Tone: friendly, clear, efficient.

Complaint handling prompts

You are a customer success manager.
Write a public response to a negative review on [PLATFORM].
Review: "[REVIEW_TEXT]".
Format: public response, max 150 words.
Tone: empathetic, professional, no apologies for things outside your control.

AI Prompts per platform — what works best where?

Not every AI responds the same way to the same prompt. Here is what you need to know per platform to get the best results.

Best ChatGPT prompts

ChatGPT (GPT-4o, GPT-5) responds well to direct task instructions with explicit formatting. Always lead with a role and specify output length.

What works:explicit role at the start, format in bullets, length specifications (“max 150 words”), system-prompt style with numbered instructions.

What does not work: vague questions without context, expecting GPT to understand your situation without you describing it.

Optimised ChatGPT prompt example

You are an experienced B2B copywriter with 10 years of SaaS experience.

Task: Write a LinkedIn post about the importance of GDPR-compliant AI for European SMBs.

Requirements:
- Length: 150-200 words
- Open with a striking statement (no question)
- Use concrete numbers or facts
- Close with a subtle call-to-action
- No hashtags in the body (add them as a comment)
- Tone: authoritative but accessible

Best Claude prompts

Claude (Anthropic) excels at long-context tasks, nuance and structured analysis. Claude responds particularly well to explicit role descriptions and detailed context.

What works: extended context (Claude handles it better than other models), XML tags for structure, asking for multiple perspectives, long-document analysis.

Optimised Claude prompt example

<role>You are a senior legal advisor specialised in European privacy law (GDPR).</role>

<task>Analyse the following privacy policy and identify potential issues.</task>

<context>
Subject: a Dutch SMB (B2B) with 25 employees.
Policy: [PASTE_TEXT_HERE]
</context>

<output_format>
1. Summary (3 sentences)
2. Issues (numbered list, each with: problem + risk + recommendation)
3. Prioritisation (which issues are urgent?)
</output_format>

Best Gemini prompts

Google Gemini responds well to prompts with concrete examples. Always provide a sample of what you want — Gemini learns better from “few-shot” examples than from abstract instructions.

What works: giving examples of desired output, integration with Google Workspace (Docs, Sheets, Gmail) via Gemini for Workspace, multi-modal tasks combining text with images or data.

Optimised Gemini prompt example

Here is an example of the tone-of-voice I want:
"[EXAMPLE_TEXT]"

Now write a similar piece about [TOPIC] for [AUDIENCE].
Make sure the tone, length and structure match the example.

Best Microsoft Copilot prompts

Microsoft Copilot integrates deeply with Word, Excel, PowerPoint and Outlook. The strength is referencing existing documents and files.

Copilot for Word

Summarise this document in 5 bullet points for [AUDIENCE].
Rewrite section 3 in a more formal tone.
Add an executive summary based on the document content.

Copilot for Excel

Analyse the data in columns B and C and identify trends.
Create a chart of monthly revenue growth.
Which product category has the highest margin? Explain why.

Copilot for Outlook

Write a reply to this email in a friendly but professional tone.
Summarise this email thread in 3 bullet points.
Create a meeting agenda based on the discussion in this email.

Best Mistral prompts

Mistral AI is the leading European AI model — built in Paris, hosted in the EU, designed for European business contexts. For organisations that want GDPR-compliant AI, Mistral is the logical choice.

Mistral responds well to direct, business-like task instructions, multilingual content (NL, DE, FR, ES, IT), legal and compliance-related tasks, and financial analysis.

Mistral prompt for European context

You are a compliance officer specialised in the EU AI Act and GDPR.

Write an internal memo about the obligations [COMPANY_TYPE] has under the EU AI Act.
Focus on: risk classes, documentation requirements and supervisory authorities.
Format: memo with date, to/from, summary, obligations per category.
Tone: legally accurate, accessible to non-lawyers.

The best AI prompts for business in 2026

The most-used and highest-rated prompts in the Custos Prompt Library — shared by teams that work with AI daily. Each one follows the Role + Task + Context + Format + Tone framework.

Executive summary writer

Turn long reports into 5-bullet briefings

Cold email opener

Personal, non-pushy first-touch emails

Meeting decision tracker

Extract decisions and action items from notes

Customer interview synthesiser

Find patterns across user research transcripts

Job description drafter

Inclusive, concrete role postings

Pricing objection responder

Calm reframes for budget pushback

Quarterly review prep

Structured performance review notes

GDPR compliance checker

Initial review of privacy documents

Get the full library with your free trial →

Save and reuse your best prompts

Custos stores your prompt library centrally, shares it with your team, and lets every member use it across ChatGPT, Claude, Gemini and Mistral — with full audit logging and GDPR compliance.

Start free trial — 14 days

No credit card required · EU-hosted · BYOK

More free tools from Custos AI

Frequently asked questions

Is the AI prompt generator free?

Yes. You can generate up to 3 prompts per day without an account or email. For unlimited generation and to save prompts to your team library, start a 14-day free trial — no credit card required.

Does the generator call an AI API?

Yes. Your input is sent to our EU-hosted backend in Frankfurt where it is processed by a large language model. We do not store your prompt content. Only an anonymised hash of your IP address is kept for 48 hours to enforce the fair-use limit of 3 generations per day. No account, no email required.

Why is there a daily limit on the free tool?

We pay for the AI usage on this free tool, so we cap it at 3 runs per IP per day to keep it sustainable. When you sign up for a Custos trial, you connect your own AI provider key (BYOK) and use it without limits — you pay OpenAI, Anthropic, Google or Mistral directly with no Custos markup.

What is a prompt template?

A prompt template is a structured starting point that combines a role, a task, context, output format, tone and constraints into a single instruction for an AI model. Templates reduce the trial-and-error involved in prompt writing and produce more consistent outputs.

Which AI models does it work with?

The prompts generated here work with any LLM that accepts system or user prompts — including ChatGPT (GPT-4o, GPT-5), Claude (Anthropic), Gemini (Google) and Mistral. Custos lets your team use all four from a single interface.

What is prompt engineering?

Prompt engineering is the practice of writing AI instructions that reliably produce high-quality outputs. It combines a clear task description with role, context, format and tone specifications. Good prompt engineering reduces hallucinations, improves consistency and cuts post-editing time significantly.

How does the prompt quality score work?

The optimizer analyses your prompt against five structural pillars: role, context, format, tone and constraints. Each missing element reduces the score. Vague language and excessive length also trigger warnings. The score gives a quick indication of how complete and specific the prompt is.

Can I share prompts with my team?

Yes — start a free trial to save prompts to your team library. After signing up, your prompts are centrally stored and available to every team member across ChatGPT, Claude, Gemini and Mistral.

What is a system prompt vs a user prompt?

A system prompt sets the AI's role and behaviour for a conversation. A user prompt is the individual message you send each turn. The prompts generated here work best as system prompts — paste them into the 'Custom instructions' or 'System' field in your AI tool of choice.