AI Prompt Builder
Generate clear, detailed prompts for ChatGPT, Claude, Gemini and more in seconds — free, no account required, and nothing leaves your device. The AI model runs entirely in your browser.
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Which AI are you writing for?
Tone
How It Works
Describe your goal
Type what you need a prompt for — a cover letter, brainstorm, explanation, or anything else. Up to 500 characters.
Pick AI & tone
Choose your target AI (ChatGPT, Claude, Gemini, or Any AI) and the tone that fits your use case.
AI builds it locally
SmolLM2-360M runs right here in your browser via a Web Worker — not on any server. Your data never leaves your device.
Copy and use
Copy your ready-to-use prompt in one click and paste it straight into ChatGPT, Claude, Gemini, or any AI assistant.
How to Generate an AI Prompt Online for Free
- Type a short description of your goal — what task, topic, or output you need from an AI assistant.
- Select which AI you are targeting: ChatGPT, Claude, Gemini, or Any AI for a general-purpose prompt.
- Pick a tone: Professional for business writing, Casual for conversational use, Creative for imaginative tasks, or Technical for precise specifications.
- Click Generate Prompt. On first use, a one-time model download (~180 MB) is required — your browser saves it locally for instant reuse and offline access.
- The generated prompt appears in the output area. Click Copy Prompt to copy it to your clipboard, then paste it directly into your AI assistant.
Tone Guide
| Tone | Style | Best for |
|---|---|---|
| Professional | Clear and business-like | Cover letters, reports, business emails, LinkedIn bios |
| Casual | Friendly and conversational | Social media posts, informal messages, everyday tasks |
| Creative | Imaginative and expressive | Brainstorming, storytelling, naming, marketing copy |
| Technical | Precise and detail-oriented | Code review, architecture decisions, technical specs |
Features
- Your data stays private: The AI model runs entirely in your browser — your goal and generated prompt are never uploaded, stored, or shared.
- No account required: Open the page and start generating immediately.
- Works with any AI assistant: Prompts are optimised for ChatGPT, Claude, Gemini, or general use.
- Four tones: Professional, Casual, Creative, and Technical to match the style of your task.
- Works offline: After the one-time model download, the tool runs with no internet connection.
- One-click copy: Copy the generated prompt straight to your clipboard, ready to paste.
- Powered by SmolLM2-360M-Instruct: A compact, fast instruction-following model by Hugging Face. One-time download of ~180 MB.
Frequently Asked Questions
Is my goal or prompt uploaded to your servers?
No. Everything runs inside your browser. Your goal and the generated prompt stay entirely on your device — nothing is sent to or stored on any server.
Is this free to use?
Yes, completely free. No account required, no usage limits, and no hidden charges.
Why is the first generation slow?
The first time you generate a prompt, your browser downloads the AI model (SmolLM2-360M-Instruct, ~180 MB) and saves it locally. After that one-time download, the model loads instantly from local storage and you can generate prompts offline too.
Which AI model powers this tool?
SmolLM2-360M-Instruct by Hugging Face — a compact 360 million parameter instruction-following model served as a quantized ONNX file via Transformers.js. It runs in a Web Worker in your browser, so no data leaves your device.
Does it work offline?
Yes. After the model is downloaded on your first use, it is saved to your browser's local storage. You can then generate prompts with no internet connection.
What makes a good AI prompt?
Good prompts are specific, provide context, state the desired format or length, and include a clear goal. This tool handles that structure automatically — you describe what you need and choose a tone, and the AI assembles a complete, optimised prompt for you.