Know that custom output styles silently override Claude Code's default coding guidance
Claude·medium signal
Output styles inject system-prompt-level instructions, but custom ones replace (not augment) Claude Code's built-in coding behavior — a quiet footgun that degrades code quality if you forget. Reach for the built-in Proactive/Explanatory/Learning styles first, and use `--append-system-prompt` for one-off tone or formatting tweaks since it's additive and preserves default behavior. Only write a custom style when you genuinely want to override the defaults.