I built 549 agent tools solo with Claude Code. What made it work was giving it one shape to write in.
I spent two years building agents that worked inside real people's Gmail, Sheets, Docs and Calendar. Along the way I learned two things. Writing tools by hand is a mess. You maintain glue, you pull heavy libraries into your tree just to handle OAuth, and every tool slowly drifts from the API it was written against. An…











