Validate Every Change, Deploy Only from main: Jekyll + GitHub Pages
How a historical Jekyll site used GitHub Actions to validate every branch and pull request while reserving production publishing for changes merged to main.
Builder · Researcher · Explainer
Systems, AI, research — built and explained with evidence.
I build and study local AI infrastructure, agent systems, software, security, mathematics, and data-driven research. This site is the durable record of the systems, experiments, failures, and ideas worth explaining.
Featured engineering story
I Let AI Agents Run a Nationwide CTF. The Hard Part Wasn't Solving the Challenges.
I ran an AI-agent pipeline in Japan's Ministry of Internal Affairs and Communications nationwide CTF. The official result was 26th place with 5,701 points. The bigger lesson was not model capability, but ownership, shared state, verification, and control-plane design.
26th place5,701 official points110 tracked challenges
Engineering
Systems & AI Infrastructure
Local inference, GPU/runtime experiments, agent orchestration, networking, and build logs.
Research
Data & Reproducibility
Statistical modeling, health data, methods, limitations, and reproducible analysis.
Foundations
Math & Algorithms
Careful explanations, proofs, algorithms, and a preserved archive of earlier work.
Latest
Recent writing
2026-10-02
BOJ 10803 — Making Squares: A Verified Recurrence Bound
Archived technical note: BOJ 10803 — Making Squares: A Verified Recurrence Bound.
Fast Fourier Transform (FFT)
A radix-2 FFT guide: DFT normalization, butterfly decomposition, polynomial convolution, and the limits of floating-point integer results.
BOJ 1199 — Euler Circuit
Archived technical note: BOJ 1199 — Euler Circuit.
Bolzano–Weierstrass Theorem
A proof that every bounded sequence in finite-dimensional Euclidean space has a convergent subsequence, with the compactness distinction.