50% Compliance, Not 0%: How a Logging Spike Almost Triggered the Wrong Architecture Rewrite

TL;DR : I thought my prompt augmentation track was completely broken (compliance=0%) and almost spent 27 hours rewriting plan-and-execute. Turns out the 0% was a regex bug — real value was 50%. 7 chapters + 4 figures (hero / decision matrix quadrantChart / 7-version timeline / data delta tables). Full version (with mermaid quadrantChart + reproducible spike commands): https://github.com/franciseliang99-dot/web-agent/blob/main/docs/blog-drafts/2026-05-w5c2-spike-story-final-en.md Project repo (MI