## Lesson — 2026-03-05T04:05:16.794Z

**Tags:** architecture, curated
**Pattern:** \.(includes|startsWith)\(['"]\\\[Totem Error\\\]['"]\)
**Engine:** regex
**Scope:** **/*.ts, **/*.tsx, **/*.js, **/*.jsx, !**/error*.ts, !**/error*.js
**Severity:** error

Do not assert error messages by checking string prefixes; use TotemError subclasses.
