What Belongs in Logs and What Does Not

Logs are letters to future-you — write them to be searched, not admired.

[ essay ]

Log events, not paragraphs. Include correlation ids, duration, outcome, and safe context — never secrets.

Log at boundaries: request in/out, external API calls, queue publish/consume, auth decisions.

Avoid debug noise in production default levels. Sample verbose traces when volume explodes.

When paging, logs should answer: what failed, for whom, since when, with what error class.

Letters unread are useless. Structure is respect for the reader at 3 AM.

— JV · Dark Heart Labs.