Postcode anchor through the resolver eval (2026-06-03)

The postcode anchor (#240) is wired into the OpenAddresses real-point resolver eval as a neural+anchor row (--postcode-anchor). The neural parse and the resolver supply the admin/place identity as before; the coordinate is taken from the postcode anchor's own centroid. So the row isolates exactly what the anchor sharpens: where, not which place. The tables below are emitted verbatim by scripts/eval/oa-resolver-eval.ts (eval figures are never hand-typed).

The anchor now carries a position-aware confidence: a digit-only code that shares its comma-segment with a street word reads as a house number, not a postcode (house numbers sit beside the street, postcodes beside the city), so its confidence is scaled down. The street vocabulary is the full USPS Pub-28 suffix table from @mailwoman/codex/us — minus the abbreviations that collide with a state code (KY is both Key and Kentucky, PR both Prairie and Puerto Rico), since those appear in the postcode's own City, ST ZIP segment. The eval then picks the highest-confidence span above a trust floor, with no "take the last span" crutch: a real trailing postcode out-ranks a leading house number on its own merit, and a span the prior flags as a house number falls back to the resolver coordinate rather than placing the address at a far-away same-shaped ZIP.

German — the resolver carries admin only, no German postcodes

| parser | locality-match | region-match | resolved | coord p50 km | coord p90 km | p99 km |
| **neural** | 77.4% | 43.8% | 99.3% | 9.9 | 66.8 | 318.2 |
| v0 (Pelias) | 79.3% | 99.3% | 99.3% | 7.0 | 16.9 | 106.8 |
| **neural+anchor** | 77.4% | 43.8% | 99.3% | 1.3 | 5.7 | 13.5 |

The anchor drops coord p50 from 9.9 km to 1.3 km (p90 66.8 → 5.7, p99 318 → 13.5), admin-match unchanged. The German parser is out of distribution (locality 77%), so the resolver lands on a coarse admin centroid; the postcode anchor — a regex plus a gazetteer, no model in the loop — carries the coordinate to the postcode's own point. It also beats the Pelias parser (v0) on coordinate by a wide margin (1.3 vs 7.0 km).

(The region-match figures here come from the codex-aware matcher: the resolver returns WOF's English exonym Saxony while OA's expected is the German Sachsen, so the eval folds both through @mailwoman/codex/de's lookupGermanState to one ISO 3166-2:DE code before comparing. Before that fix both parsers read ~0% on Saxony purely from the language mismatch. The remaining neural gap is real and concentrated in the Berlin city-state: per-state, neural emits a resolvable region for Saxony 87.5% of the time but for Berlin only 0.1% — Berlin, Berlin collapses region into locality and the OOD parser drops the duplicate. v0 reaches 99.3% because it emits the region in both.)

US — the resolver already loads postalcode-us.db

| parser | locality-match | region-match | resolved | coord p50 km | coord p90 km | p99 km |
| **neural** | 97.3% | 99.9% | 100.0% | 3.3 | 11.0 | 277.4 |
| v0 (Pelias) | 95.3% | 99.4% | 99.7% | 3.3 | 11.7 | 368.6 |
| **neural+anchor** | 97.3% | 99.9% | 100.0% | 2.8 | 11.2 | 25.7 |

Even where the resolver already resolves ZIPs, the anchor helps on the tail: p50 tightens 3.3 → 2.8 km and the p99 collapses from 277 km to 25.7 km. The tail is the handful of addresses whose neural parse resolves to the wrong admin centroid; the postcode is a more reliable coordinate than a mis-resolved city, so swapping it in caps the error at ZIP granularity. (Getting here meant closing the house-number trap: a leading 5-digit that is a valid ZIP in another state — 32147 Bio Station Lane, Polson, MT 59860 — must not win over the real trailing ZIP. The position prior plus the trust floor handle it; before them, that trap put the US p99 at 889 km.)

Takeaway

The fusion is a clean win in both directions: it supplies postcode-level coordinates for the locales whose postcodes the resolver's shards do not carry (DE/ES/IT/NL/FR), and it tightens the tail even where they do (US), because a real postcode out-resolves a mis-parsed admin centroid. It is the postcode tier the eval's own note promised, between the admin-centroid tier and the future street-level (TIGER) tier — and the position-aware confidence means it runs on the anchor's own judgment, not an eval-side crutch.

Reproduce:

node --experimental-strip-types scripts/eval/oa-resolver-eval.ts \
  --eval data/eval/external/openaddresses-de-sample.jsonl --limit 1500 --default-country DE \
  --model <onnx> --tokenizer <tok> --model-card <card> \
  --wof /mnt/playpen/mailwoman-data/wof/admin-global-priority.db \
  --postcode-shards <us.db>,<intl.db> --postcode-anchor