research-the-limit

Before asserting that a tool, library, or system cannot do something, check a primary source — its own docs, --help, source, or what is actually installed — rather than asserting from memory. Use whenever about to write or say "X cannot do Y", "there is no way to Y", or plan around a limit nobody has actually checked. Not for judging whether a check's verdict can be trusted (verify-the-instrument) or for reasoning with no command or document available to settle it (sanity-check) — this is specifically for a claimed capability boundary that a primary source can confirm or refute.