Codex

Handing Off Claude Code / Codex Sessions Between Two Macs: Syncthing + session-index-viewer

2026-06-19T10:00:00+09:00

Background

The pain point is straightforward: I have two MacBooks (A and B), and I heavily use both Claude Code and Codex for work and side projects on both machines. I wanted to switch seamlessly between them and resume previous sessions at any time.

Since their actual session data is stored locally as indexable session files (while state is also tracked upstream), as long as the session files on both sides are synchronized, I can resume right where I left off from either computer. Solving the synchronization problem was the first step.

When AI Pushes Back: Alignment Philosophies of Claude vs. Codex Through a Misread Algorithm Problem

2026-05-22T22:00:00+09:00

Background

In January 2017, I visited Tokyo for the second time in my life on a tourist visa to take the graduate entrance exam for the Department of Creative Informatics at the University of Tokyo.

Creative Informatics was somewhat unusual because it had no written math exam—only on-machine programming. While preparing for the exam, I worked through many past papers, finding several genuinely intriguing problem designs (far more interesting than routine LeetCode grinding).