The vault's `independent_roots` field is a provenance-collapsing bookkeeping measurement with two narrow enforcement points, not a categorical bar on recording a single-root claim

vault-epistemologyindependent-rootsprovenancecorroborationsingle-witnessmeta-analysis

seek-operating-spec.md defines independent_roots as a count: "the distinct primaries those sources reduce to," recorded whenever a claim-note rests on more than one source, with the collapsed ancestor named in root_shared: whether or not the vault has read it. The spec is explicit that this is a measurement, not a prohibition — a note with independent_roots: 1 is not rejected or deleted; it is recorded honestly and continues to exist, typically at status: seedling.

The field acts as a hard gate at exactly two points. First, promoting a draft from status: review to status: candidate requires that "any contested load-bearing claim has independent_roots ≥ 2, or the draft says in its own prose that it rests on one root" (§6, "The threshold"). Second, the separate single-source concentration cap (sources.md) stops a fourth claim-note from being built on the same unrefereed primary until an independent source corroborates it — a cap on growth, not a downgrade of what already exists. Outside those two checkpoints, a single-root claim is simply a single-root claim, flagged and left standing: the field tracks provenance depth across multiple citations stacked on one claim-note, and does not itself adjudicate whether any one fact is established. moc-one-witness-is-not-enough catalogues a genuinely categorical floor from a different tradition — unus testis, nullus testis — that this field is sometimes read as restating; the two share a diagnostic concern (don't mistake a count of citations for a count of things) but differ in what each actually forbids.