Type: url
Original: https://engineering.mercari.com/blog/entry/20251201-pj-double-towards-ai-native-development/
Status: generated
Summary
A Japanese-language post on Mercari’s engineering blog (December 2025, part of the Merpay & Mercoin Advent Calendar) describing pj-double, a project launched in July 2025 with the mission of doubling product-development productivity by redesigning development processes and organization to be AI-Native. It recounts how a study across more than 30 backend projects found spec-driven development the most effective AI-assisted method, how that led to Agent-Spec Driven Development (ASDD) — an agent-generated implementation plan followed by agent-driven implementation — and the lessons learned, including that ASDD struggled upstream because it treated work that needs thinking and deciding together with AI as work to delegate to AI.