I made Claude Code think about the design before it writes code

Coding agents build what the ticket says and miss what it doesn't say. You ask for a CSV export, it builds the whole file in memory, and it falls over on the biggest customer. Or you ask for a simple filter and get a plan with Kafka.

So I made a skill for Claude Code (also works in Codex, Cursor and others).

Small fixes stay small. For bigger features, Claude first does some rough math on load, reads how the code works now, and writes a short plan with trade-offs and questions for you. Then it codes. If you ask, it also draws the architecture in the terminal.

I tested it by running the same tasks with and without the skill. The plans got real numbers and open questions instead of guesses. A typo fix stayed a typo fix.

npx skills add Baukaalm/system-design-first

Free and open source (MIT): https://github.com/Baukaalm/system-design-first