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200+ prompts, ready to ship
12-month posting plan in 60 sec
Brand voice doc in 4 steps
Runway / Pika / Sora / Veo formats
Role, constraints, tone, output format. Four fields, one production-ready system prompt for a custom GPT or AI agent — copy-paste, no boilerplate to strip out.
For an agent's function, not your brand's writing voice — for brand voice, use the Voice Persona Builder instead.
Role, constraints, tone, output format.
Inputs stay local. Email unlocks the pack.
Paste straight into a custom GPT or agent.
What is this GPT/agent, and who is it for?
One per line — hard rules it must never break.
How should it sound?
One per line — anything else it should always or never do.
Role is required.
— Feedback · 30-second form
One missing field, one weird output, one tool you wish existed — tell me. I read every reply.
Why this generator exists
I build custom GPTs and agents for clients weekly. The model is smart enough almost every time — what breaks is the wrapper. Wrong tone for the channel, no output-format rule, no fallback for when a request conflicts with a constraint.
This generator forces those four decisions up front: who the agent is, what it must never do, how it should sound, and exactly what shape its replies take. That's usually 80% of what separates a demo from something you can actually ship to users.
Note this is a functional agent prompt, not a brand-voice document — if you're trying to make an LLM write marketing copy that sounds like your company, use the Voice Persona Builder instead.
Waseem, building from Bali · info@skynetjoe.com
More free tools
Writing brand copy, not a functional agent? Use the Voice Persona Builder. Need the full review doc with guardrails and escalation rules, not just the prompt? Try the AI Agent Spec Writer. Chaining several prompts together? Use the Prompt Chain Builder, or book a free discovery call to have this agent actually wired into your stack.
Quick answers
No — different job. The Voice Persona Builder produces a brand voice profile for writing copy that sounds like your brand (marketing, emails, social posts). This tool produces a functional system prompt for an agent or custom GPT — what it's allowed to do, what tone to use, and exactly what format to reply in. If you're building a brand-voice writing assistant, start with the Voice Persona Builder. If you're building a functional agent or GPT, use this one.
Any platform that accepts a system message or custom instructions — ChatGPT custom GPTs, Claude Projects, Gemini Gems, or a system prompt field in an agent framework like LangChain, CrewAI or n8n's AI Agent node.
It's the single most common failure mode I see — a well-designed agent that replies in the wrong shape. A support bot that returns markdown headers in a plain-text chat widget looks broken even when the reasoning is correct. Locking the format up front avoids that entirely.
Your inputs and the generated prompt are built entirely in your browser and saved to localStorage. The only thing sent to my CRM is the email you enter to unlock the full pack.