How I built an AI Manual Assistant between warehouse shifts (and why it hallucinated about charcoal)

#showdev #programming #react #ai

Marcin Firmuga - 22 years (Poland)

The physical world is still stuck in the 90s.

I spend my days picking orders in a warehouse, surrounded by machinery and heavy boxes. But my nights belong to my laptop.
For the past few months, I’ve been obsessed with one question:

Why are we still using 100-page paper manuals in 2026?

I decided to fix this by building GuideAI :)

The Concept

The idea is simple:

Upload a PDF manual.
AI parses the data into a knowledge base.
Generate a QR code for the physical device. *Scan and chat with the machine in plain English or Polish. *

The "Charcoal" Incident (Hallucinations are real)

While stress-testing the logic with Llama 3 (via Groq),
I asked the assistant how to fix a modern Beko washing machine.

The AI confidently told me to "refill the charcoal tray" and check for soot buildup. Apparently, my LLM thought I was living in the 19th century.

This taught me a huge lesson:
Garbage in, garbage out. Fine-tuning the RAG (Retrieval-Augmented Generation) and switching to more precise models like GPT-4o-mini became my top priority to ensure users don't start putting BBQ briquettes in their laundry rooms.

The Stack

As a solo dev, I had to choose a stack that lets me move fast:
Frontend: React + Tailwind CSS.
Backend/Auth: Supabase **
(Recently finished a deep dive into Google OAuth and RLS).
**AI Pipeline: Groq (for speed) and OpenAI (for precision).
Deployment: Vercel.

I've spent over 700 hours on my projects, deleted >20,000 lines of code. It was brutal, but for the first time,
I have a product that actually ships.
(payment is still not configured :) )

Where it stands now

The MVP is live at
https://guide-ai-gold.vercel.app/#

Full Dashboard: Manage your "fleet" of devices.

Scan Analytics: See how many times people actually scanned your QR.

GDPR Ready: Just finished the Terms and Privacy pages to make it "official."

I need your "Dev" eyes

I’m looking for fellow builders to:
Try to break the AI: Upload a weird manual and see if it still talks about coal.
UX Review: Does the QR-to-Mobile flow feel smooth?

Roast my stack: Is there a better way to handle the PDF-to-Knowledge-Base pipeline?

I’m building this in public as HCK_Labs. From the warehouse floor to the cloud—it’s been a wild ride.

Check it out: GuideAI

And... If you want to be my first $1 after months of work :)
I'm and my socials is here. THANKS YOU MATE :)
https://linktr.ee/marcin_firmuga

About the Author

I’m Marcin Firmuga. Solo developer and founder of HCK_Labs.

My journey started with PC Workman, an open-source, AI-powered PC resource monitor built entirely from scratch on dying hardware during warehouse shifts in the Netherlands.
It was the first time I gave my code a real home.

Before this: game translations, PC technician internships, warehouse operations in multiple countries, and countless failed projects. But something changed. I stopped just building; I started shipping.

After 700+ hours of code on my previous tools, GuideAI is my next big step. It’s the result of the same 3 AM all-nighters, energy drinks, and the refusal to let “good enough” be the end. I’m still the guy from the warehouse, but now I’m making the physical world talk.