Get the negotiated rate a specific payer pays a specific NPI for a specific billing code, in a state. Resolves at query time through the canonical graph + inverted indexes (no precomputed edge table) and returns the most provider-specific rate with source lineage, methodology, evidence type, and Medicare-PUF corroboration. UHC custom codes are resolved automatically. Covers all built payers. Near-zero dollar rates (positive, under $1 — the ghost class the benchmark path excludes) are never picked over a plausible rate; if one is all that matched, it is served flagged is_ghost_candidate at confidence 0.2 with a caveat, never as a real price.