I went from ¥100k/month as a university student, to ¥600k/month juggling multiple gigs, to exactly zero when my employer pulled the plug. Six months after that, I rebuilt everything around an autonomous Claude Code setup and I'm at ¥1.2M/month in revenue. This series opens up that setup — the actual code, the actual numbers.
Why this setup works
The first wall I hit after making Claude Code the core of my side business was context decay.
Every time a session ends, everything you built up disappears: the architecture you settled on in the last conversation, the implementation you tried and abandoned, the reasoning behind "we're not going in that direction." You have to explain all of it again in the next session. Use it eight hours a day and hundreds of thousands of tokens of back-and-forth evaporate in a week. No matter how smart the model is, it can't be the foundation of a solo business if the context resets to zero every time.
The idea that solves this at the root is an external brain. Every conversation log with Claude is saved in real time, and every night those logs are automatically ingested into an Obsidian vault (a Markdown-based personal wiki) and structured. Project decisions go to wiki/projects/, technical lessons to wiki/learning/, this week's open questions to wiki/hot.md — knowledge keeps accumulating across sessions, maintained mechanically.
