DAVID
DER.

A software workshop. AI experiments, hobby apps, and notes from building them.

richmond, va

now building — dread index

7 apps · 2 essays · 2026

Jev Frogger Arcade Frogger where an AI makes every hop, live — four typed decisions a second, probabilities on show. LIVE2026 02

Dread Index Horror ratings on five axes — is it the kind of scary you actually want? LIVE2026 03

Chess Tempura The 2014 command-line chess, re-fried in TypeScript. All 685 WCC games inside. LIVE2026 04

Starfighter Deep space in one HTML file — planets, asteroid belts, throttle and boost. LIVE2026 05

Wake Up Neo Follow the white rabbit. A terminal in the Matrix, in your browser. LIVE2026

06

Desert Walk A top-down pixel-art desert to wander. Fixed-timestep simulation. LAB2026

07

Shandalar Web A love letter to the meta layer of Magic: The Gathering, 1997. LAB2026

08

Dynasty Local-first dynasty fantasy football analytics. Value over replacement. LAB2026

Writing

2026-10 · experiments

Jev Decision Model Applied to Guardrails

A decision model that never reads the conversation, tested as guardrails against prompt rules, OpenAI guardrails, and LLM judges given the same questions.

2026-10 · experiments

TELL, an AI-Text Detector That Shows Its Work

What perplexity and Binoculars measure, what I took from them, the giveaway words, and what a 115,000-word document still gave away after the obvious tells were gone.

2026-09 · experiments

Frogger Played by Jev, Zero Shot State Machine Solver in 180ms

An AI plays Frogger one API call at a time. Two wrong assumptions, both fixed by the agent that made them, and a second half to the scripts argument.

2026-09 · experiments

AI Agents: The Case for Scripts in the Skills Spec

Two experiments, $6.09 of API calls, and a recession the model missed.

2026-04 · field notes

I Pointed Karpathy's LLM Wiki at the D&D Rulebooks

~$50 and seven hours of unattended LLM time to learn that RAG is doing too much work for the wrong problems.

draft

One VM, many apps: the $25 platform

Subdomains, SQLite files, and a justfile — how every project here gets hosted.

I'm David — by day I work in tech; by night I give odd ideas just enough software to find out if they're good ones. Some of these will graduate to real homes. Most will happily stay small.

david.der@gmail.com · github.com/david-der

DAVIDDER.