---
id: "lib-2026-10-31-isucon-2026-human-off-the-loop-failed"
type: "library"
title: "ISUCON 2026: human-off-the-loop failed"
title_original: "ISUCON2026参加記: ヒューマン・オフ・ザ・ループ失敗"
lang: "JA"
org: "Zenn (ojey)"
source_type: "Practitioner post"
date: "2026-10-31"
week: "2026-W44"
url: "https://nosov.ai/library/lib-2026-10-31-isucon-2026-human-off-the-loop-failed/"
original_url: "https://zenn.dev/ojey/articles/isucon2026-report"
tags: ["ai technology", "future of work"]
---

# ISUCON 2026: human-off-the-loop failed

Original title: ISUCON2026参加記: ヒューマン・オフ・ザ・ループ失敗

## English summary

Two-person team ran 4 agent sessions (Claude Code x3, Codex x1) in merge/investigate/fix roles after 5 rehearsals encoded as skills; 129 issues (25 rejected), 102 PRs (86 merged), about 77 benches, about 130 commits; 3 hours flat at 23-25k because agents kept polishing SQL while the ceiling was architectural; moving heavy work to another server took it to 42k. Measured case of agents optimising locally without a human reframing.

Original: https://zenn.dev/ojey/articles/isucon2026-report