What does an "eval loop" look like for Magento prompts?

An eval loop is a tight write → verify → correct cycle, not a one-shot. Concrete Magento setup: (1) prompt produces files, (2) a PostToolUse hook runs php -l + vendor/bin/phpcs --standard=Magento2 + vendor/bin/phpstan analyse, (3) any failure feeds back into the conversation as a follow-up message automatically, (4) the model fixes it without you typing. Five iterations max; if it still fails, your CLAUDE.md is missing a rule. The eval loop is what turns Claude Code from "impressive demo" to "actually shipping". Without it you're back to copy-pasting code into Travis and waiting 10 minutes.