A double-hyphen separator collides with an easy authoring typo: an accidental extra "-" in a kebab-case slug (e.g. "hello--world") silently misparses as slug "hello" + an invalid date, dropping the article from the index with no visible error. "~" isn't something anyone would type by accident while writing a normal slug, and (like "-") is in the URI "unreserved" set, so it never needs percent-encoding either. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01AXSVPS3UmmASiiprPfcnUd