Custom AI prompts are saved instructions you reuse when you write similar messages. They are useful when a standard button such as “rewrite” is too vague: you can specify the audience, tone, format, and the limits the answer must respect.
On an Android AI keyboard, the practical workflow is simple. Write a rough draft in the app where the conversation is happening, select the text, then run a prompt against that draft. In Synapse, grammar correction, translation, and tone changes work through this same deliberate, selected-text flow. The prompt helps shape your draft; it should not replace your judgment.
Start with the job, not a clever phrase
A dependable prompt identifies four things:
- The job: rewrite, shorten, translate, summarize, or draft a reply.
- The reader: a client, friend, manager, customer, or group chat.
- The constraints: a length, tone, facts that must stay unchanged, or a question to include.
- The source text: your actual draft, notes, or message context.
For example, instead of saving “make this better,” save: “Rewrite this as a professional, friendly client update. Keep dates, prices, and commitments exactly as written. Use two short paragraphs and end with one clear next step.” That tells the AI what success looks like and which details it must not alter.
Five prompts worth saving
1. Grammar without a formal voice
Fix grammar and punctuation. Keep my wording, level of formality, and message length close to the original.
Use this when the point is already right and you only want cleanup. If the output suddenly sounds unlike you, the prompt succeeded at grammar but failed at voice—edit it before sending.
2. A concise client reply
Turn this into a concise, professional reply for a client. Keep every factual detail. Confirm what I can do, name any missing information, and ask one specific next-step question.
This is useful for a rough draft, not a blank request. For more client-message patterns, see AI prompts for freelancer client messages.
3. A calm boundary
Make this polite and firm. Remove blame and sarcasm, keep the boundary clear, and do not promise anything I did not write.
Read this output especially carefully. An AI can soften a message, but it cannot decide what you are comfortable agreeing to.
4. Translation with a tone check
Translate this into [language] for a friendly everyday chat. Preserve names, numbers, links, and dates. Then provide a brief English back-translation so I can check the meaning.
Translation quality varies with language pair and context. Never treat a generated translation as a legal, medical, safety, or contractual text without qualified review.
5. A WhatsApp project update
Turn these notes into a short WhatsApp project update. Use bullets only if they improve clarity. State what is complete, what happens next, and any blocker. Do not invent a deadline.
For a full WhatsApp workflow, see how to use an AI keyboard in WhatsApp.
The limits that matter
AI does not know whether your price, deadline, promise, or personal fact is correct. It can make incorrect assumptions sound confident. Treat every output as a draft and confirm the parts that matter: names, amounts, dates, links, commitments, and claims about another person or business.
Do not paste secrets, passwords, card information, private client data, or sensitive health and legal details into a prompt. With Synapse, normal typing stays on-device; text is processed only when you explicitly select it and run an AI prompt. Read the privacy guide before using any keyboard or AI writing service for sensitive work.
A quick review before sending
Before you send an AI-assisted message, ask:
- Is every fact, number, name, and date still right?
- Does this sound like me and fit the relationship?
- Did it add a promise, excuse, or conclusion I did not make?
- Would I be comfortable if the recipient asked a follow-up question?
If the answer to any question is no, edit the draft or start again with a clearer constraint. The goal of a custom prompt is not to automate your communication. It is to make the first useful draft faster while keeping you responsible for the final message.