Marigold — a private ofrenda that catches the ghosts AI writes into our memories

Hacktoberfest Open-Source AI Challenge: Ghost in the Machine Submission 👻🌼

This is a submission for the Hacktoberfest Open-Source AI Challenge Week 4: Ghost in the Machine

For Día de los Muertos, families build an ofrenda: an altar with photos of the people they've lost, their favourite foods, marigolds to guide them home, and the stories that keep them close.

Marigold helps you build one on your own computer:

The photos are public-domain archive photos and the memories are fictional; with your own family photos, it's their faces on the ofrenda.

My take on "Ghost in the Machine": the scariest ghost in AI isn't a spooky one. It's the confident little invention. Ask a model to write about your grandmother and it may "remember" a town she never lived in, a year that's off by one, or a sister who never existed. In most apps that's a bug. In a remembrance, it's a ghost that rewrites someone's life.

So Marigold has a ghost check. It doesn't just tell the model to stick to the facts; it checks. Every name, place, number, month and weekday in the written text is compared against everything you wrote and everything the model saw in the photos. Anything that came from nowhere is flagged as a 👻 and highlighted, so you can remove it, or add it to your memories if it's true. Here it is catching a city that was planted in a test:

Try it: download marigold-win-x64.zip (or the macOS/Linux build) from Releases, install Ollama, run ollama pull gemma3:4b, and double-click marigold. It opens in your browser at 127.0.0.1:5180.

A private, offline ofrenda for the people you remember.

Add a few old photos and write down what you remember: what they always said, what they cooked, the song they hummed. A local open-weight model ( Gemma 3 4B via Ollama ) looks at each photo and writes a short remembrance using only what you gave it. Marigold then builds an ofrenda page with their photos, your words and their favourite things, saved as one HTML file you can keep, print or share.

A language model writing about someone you loved will sometimes "remember" things that never happened: a town she never lived in, a year that's wrong, a name nobody had. In a remembrance, that's the worst kind of mistake.

So Marigold doesn't just ask the model to stick to the facts. It checks. Every name, place, number, month and weekday…