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PromptPro

Personal Product Aug 2025
Chrome MV3 OpenAI API FastAPI JavaScript MongoDB Prompt Engineering

Problem Statement

Most people write terrible prompts. Not because they're bad at thinking — because prompting is a new skill and nobody has muscle memory for it yet. You type something vague into ChatGPT, get a mediocre response, and blame the model. But 80% of the time, the prompt was the problem.

Hypothesis

What if prompt improvement happened inline, right where you're already typing? No separate tool, no copy-pasting into a "prompt optimizer" — just highlight your text, click a button, and get a better version. Like Grammarly, but for talking to AI.

Solution

PromptPro is a Chrome extension that injects directly into ChatGPT and Microsoft Copilot, adding an "Improve" button next to the input box:

  • Inline enhancement — select text or place cursor in any supported input, click Improve, get a restructured prompt with better clarity, structure, and specificity
  • Persona-based refinement — optionally refine with a persona (Teacher, Executive, Technical Reviewer) to shape the tone and depth
  • One-click apply — the enhanced prompt replaces your original text directly in the input box. Hit enter and go
  • BYOK (Bring Your Own Key) — runs on your personal OpenAI API key, stored in Chrome sync storage. Never leaves your browser
  • Zero tracking — no analytics, no telemetry, no prompt logging. Your prompts stay yours

Screenshots

PromptPro - Improve Prompt button on ChatGPT with enhancing spinner
Inline on ChatGPT — "Improve Prompt" button with enhancing spinner
PromptPro - Enhanced prompt result with Role, Task, Context, Parameters
Enhanced result — structured with Role, Task, Context, and Parameters

Technical Architecture

Key in chrome.storage.sync. Background worker mediates all network calls. Optional FastAPI + MongoDB backend scaffolded for future prompt history.

Key Product Decisions

  • Inject, don't redirect. The extension lives inside ChatGPT and Copilot, not in a separate tab. Users shouldn't context-switch to improve their prompts — it should happen where they already are
  • Enhancement, not generation. PromptPro improves what you wrote, it doesn't write for you. This preserves intent while adding structure — which is what most prompts actually need
  • Personas are optional, not default. Most users just want "make this clearer." Power users get persona modes. Layering complexity rather than frontloading it
  • Backend exists but sleeps. The FastAPI service is scaffolded for prompt history and team features, but v1 is fully client-side. Ship the simplest thing that works, then layer on

Impact & Metrics

2 Sites
ChatGPT & Microsoft Copilot supported
MV3
Modern Chrome Manifest V3 architecture
Open Source

Lessons Learned

  • The best AI tools are invisible. Nobody wants to learn a new interface to use AI better. Embedding the enhancement directly into the tools people already use eliminates adoption friction entirely
  • Prompt quality is a UX problem, not an AI problem. The models are capable enough — the bottleneck is the human-to-model interface. Improving that interface is where the leverage is
  • MV3 is painful but worth it. Chrome's Manifest V3 restrictions (no persistent background pages, limited APIs) forced cleaner architecture. The service worker pattern is actually better for this use case