This is a submission for Weekend Challenge: Dog Days Edition
🐾 Cat Guardian — Protect. Identify. Find.
I live with seven cats: Kiara, Golia, Meias, Vaquinha, Tigrinha, Peluda, and Gamora. They all have different personalities, different appearances, and different routines.
And, like many pet owners, there is one thing that has always worried me: What if one of them gets lost?
That question became the starting point for Cat Guardian.
What I Built
Cat Guardian is a privacy-first digital safety passport for cats.
The idea is simple: give each cat a digital identity containing the information that could actually help if they ever go missing.
The platform provides:
- 🐈 Digital identity for each cat
- 🩺 Health records and vaccination tracking
- 🧠 AI-assisted visual identification
- 🏷️ Dynamic QR collar tags
- 🚨 Lost Mode
- 📱 Public rescue passport
- 🔐 Privacy-preserving contact between finder and owner
- 🌎 English and Brazilian Portuguese localization
The problem
When a pet goes missing, useful information is often scattered across photos, veterinary records, paper documents, and the owner's memory.
Traditional collar tags can also expose personal information such as phone numbers or addresses. I wanted a different approach.
The QR code attached to the collar doesn't expose the owner's contact information. Instead, when someone finds the cat, they can scan the QR code and access a public rescue profile.
If the owner has activated Lost Mode, the finder can submit a sighting. The owner is then notified through a secure backend relay.
Owner
│
▼
Cat Guardian
│
├── Digital Identity
├── Health Records
├── AI Profile
└── QR Collar Tag
│
▼
Lost Mode
│
▼
Finder scans QR
│
▼
Public Rescue Card
│
▼
Submit Sighting
│
▼
Owner notified
The goal isn't to replace GPS trackers or microchips.
It is to make the information surrounding a lost pet available, structured, and safer to share.
Why AI?
I didn't want to add AI simply because this was an AI-related challenge.
I wanted to use it where it could provide practical value.
Gemini is used to analyze visual characteristics such as coat patterns, eye color, and distinctive markings and generate a structured identification profile.
The application also provides informational preventive wellness guidance, while explicitly keeping medical diagnosis and treatment outside its scope.
AI-generated profiles are also localized according to the user's language.
Demo
The application includes a Demo Mode, so you can explore the main experience without creating an account.
The demo contains my seven cats:
Kiara · Golia · Meias · Vaquinha · Tigrinha · Peluda · Gamora
Try the Lost & Found flow with the demo data and explore how a finder would interact with a cat's public rescue passport.
Key flows
1. Register a cat
Create a digital identity and add health information.
2. Generate a QR collar tag
The QR code points to the cat's public safety passport.
3. Activate Lost Mode
The owner can mark the cat as missing.
4. Finder scans the QR code
The finder sees the relevant rescue information without seeing the owner's private contact details.
5. Submit a sighting
The finder can send information about where and when the cat was seen.
6. Owner receives the notification
The backend relays the sighting to the owner through Resend.
Code
The project is open source and built with:
- React 19
- Vite 6
- TypeScript
- Supabase PostgreSQL
- Supabase Auth
- Row Level Security
- Gemini
- Ollama
- Mistral 7B
- OpenCoder 8B
- Resend
- i18next / react-i18next
- Vitest
- React Testing Library
- ESLint
How I Built It
This project was also an experiment in AI-assisted software engineering.
I used my own AI Software Engineering Framework 2.0 to orchestrate the development process.
The goal was not simply to ask an LLM to generate the application.
Instead, I treated AI agents as specialized members of an engineering workflow.
Human Supervisor
│
▼
Chief of Staff
│
▼
Risk Router
/ | \
▼ ▼ ▼
Mistral OpenCoder Gemini
\ | /
\ | /
Jidoka
│
▼
Human Approval
│
▼
Merge
Risk-based agent routing
Simple and low-risk tasks were delegated to local models running through Ollama.
🟢 Mistral 7B
Used for tasks such as:
- documentation
- simple UI changes
- repetitive work
🟡 OpenCoder 8B
Used for:
- CRUD
- forms
- implementation tasks
🔴 Gemini
Used for higher-risk tasks such as:
- authentication
- Row Level Security
- AI integrations
- architectural decisions
This allowed me to keep the more capable model focused on tasks where it provided the most value.
Jidoka Quality Gate
Every implementation had to pass a validation pipeline:
Lint
↓
Typecheck
↓
Tests
↓
Build
↓
Human Approval
If a validation step failed, the workflow stopped instead of allowing the problem to propagate.
This follows the Jidoka / Andon Cord principle from my framework:
When an anomaly is detected, stop the process and fix it before continuing.
The final release candidate passed:
| Gate | Result |
|---|---|
| ESLint | ✅ PASS |
| TypeScript | ✅ PASS |
| Vitest | ✅ 21/21 PASS |
| Production Build | ✅ PASS |
Privacy-first architecture
The public rescue passport deliberately does not expose:
- owner's email
- phone number
- physical address
The finder communicates through a backend relay.
Sightings are persisted in PostgreSQL and the owner is notified through the Resend API.
This creates a simple separation:
Finder
│
▼
Public Rescue Passport
│
▼
Sighting
│
▼
Backend
├── PostgreSQL
└── Resend
│
▼
Owner
The finder can help without gaining direct access to the owner's private contact information.
Internationalization
English is the default language, with Brazilian Portuguese as a secondary locale.
I also wanted AI-generated information to respect localization.
The localized AI profiles are stored in PostgreSQL using JSONB:
{
"en": {
"description": "...",
"personality": "..."
},
"pt-BR": {
"description": "...",
"personality": "..."
}
}
This keeps the cat's identity data together while allowing the presentation to adapt to the user's language.
Design System
The application uses a custom Midnight Guardian design system.
The visual language combines:
- Midnight Navy
- Lavender
- Emerald
- Amber
- Coral
The goal was to make the application feel like a safety product rather than a generic pet CRUD application.
🔐 Privacy & Safety
Privacy was treated as a product requirement rather than an afterthought.
The public QR page is intentionally limited to information that can help identify and recover the cat.
Owner PII is not rendered publicly.
The system also does not attempt to provide veterinary diagnosis.
Cat Guardian provides informational preventive wellness guidance and does not replace professional veterinary advice.
🚧 Current Limitations
Cat Guardian is a hackathon prototype.
It does not currently provide:
- real-time GPS tracking;
- GPS collar hardware integration;
- veterinary diagnosis;
- guaranteed pet recovery.
These could be explored in future versions.
For this challenge, I intentionally focused on the digital identity, QR-based rescue flow, privacy-preserving communication, and AI-assisted identification.
🎯 What I Learned
The biggest challenge wasn't building the features.
It was deciding what not to build.
It would have been easy to add GPS, maps, mobile applications, IoT devices, blockchain, push notifications, and many other features.
But the core idea was much simpler:
Give a cat a digital identity that can help protect, identify, and reunite them with their owner.
Everything else had to support that idea.
And the project became much stronger because of that constraint.
🐾 Built for seven cats
Cat Guardian started with a very personal question:
What information would I want to have if one of my cats disappeared tomorrow?
I would want their photo.
Their identifying characteristics.
Their health information.
Their vaccination history.
Their microchip information.
And, most importantly:
I would want the person who found them to have a safe way to contact me.
That's Cat Guardian.
Built for:
Kiara · Golia · Meias · Vaquinha · Tigrinha · Peluda · Gamora
🐾
Prize Categories
I'm submitting Cat Guardian for:
🏆 Best Use of Google AI
Gemini is used meaningfully in the application for:
- AI-assisted visual identification profiles
- feline characteristic analysis
- preventive wellness assistance
- localized AI-generated content
Google AI is also used as the high-risk agent in the AI-assisted engineering workflow.
🔗 Links
Built for the DEV Weekend Challenge: Dog Days Edition.
