Session handling sharpened since 3.0.
lucia-auth ships a well-documented threat model and defaults that embody it. A mid-release scope change introduced one rough edge around adapter contracts; otherwise, read the code and sleep well.
§1 · Context
Lucia is the rare auth library that reads like it was written by someone who has been on call during a credential-stuffing event. The API forces you to think about session lifecycles, regeneration, and revocation — it does not let you skip those concerns to save three lines.
§2 · Findings
One medium finding: the adapter contract for getSessionAndUser is
underspecified in the docs and two community adapters returned slightly
different error shapes; the library's reconciliation of those shapes is
correct but surprising.
Five low findings are doc nits.
§3 · Bottom line
Use it. The 3.2 release is the one to pin to.