Night Guard: an open-model guard that watches out for kids in game chats

Description and use

Night Guard is a local app that uses the Gemma LLM to detect pressure tactics in children’s online chats, alerting parents and warning kids in plain language.

Problem

Parents cannot read every chat their kids have in Roblox, Discord or TikTok, while child‑safety incidents rise rapidly.

Outcome

Night Guard achieved 70/70 valid analyses, flagged all 36 risky chats, and reduced false alarms to 3/34 (9%) on a fictional test set of 70 chats.

Workflow

• 1. Install Night Guard on the child’s computer. 2. The Chrome extension or screen guard monitors incoming messages. 3. Messages are sent to the local Gemma model via Ollama. 4. The model returns detected tactics, risk level, and exact quotes. 5. The app displays a kid‑friendly warning and a parent dashboard with risk level, flagged phrase, and next steps.
• 6. Optional push notification to parent’s phone.
• 7. The system updates the kid’s “hero” level as they learn to spot tactics.

Evidence

Night Guard reads messages on the family's own computer and highlights possible pressure tactics

Source

Results on a fictional test set of 70 chats (36 risky, 34 safe)

Source

The real Night Guard runs on the family's computer with Gemma, where chat analysis stays on the device

Source