Two changes that make the verifier accept more honest grounding without
relaxing what STRICT means.
1. Strip trailing citation parentheticals at extraction time.
`extract_quotes` and `extract_claim_spans` now drop a single trailing
`(Source: ...)` / `(citing X)` / `(https://...)` parenthetical
before returning. The Pikachu real-corpus case: model wrote the
verbatim source sentence and appended `(Source: https://...)`. The
prose IS in the corpus — only the inserted citation broke substring
match. Now substring fires; STRICT recovered.
Conservative regex: only strips when the parenthetical content
starts with a citation cue word OR contains a URL. A genuine prose
parenthetical like "Pikachu (a Pokémon species) lives in forests"
stays.
2. Paraphrase strategy as a 4th verifier method.
In the span path, items that fail substring match get a
token-coverage probe. Tokens >=4 chars from the span; if >= 85% of
them appear in the normalized base context, count the span as
paraphrase-verified. Paraphrase items contribute to n_verified;
verifier_method flips to 'paraphrase' when any soft-verified items
are present so an auditor can tell.
Gated by `_is_prose_span`: a list of proper nouns ("Keanu Reeves,
Laurence Fishburne") has no lowercase content tokens >=4 chars and
falls through to the entity strategy where proximity policy can
tight-cluster check. Real prose spans ("Pikachu is a species of
Pokémon creatures...") have multiple lowercase content tokens and
qualify for paraphrase.
Soft-signal note (from CLAUDE.md soft/hard rule): paraphrase is
heuristic, not byte-equivalence. The hard chain still records the
classification — verifier_method='paraphrase' is the explicit marker
that an audit reader can use to distinguish lexical-verbatim from
paraphrase-overlap. Quote strategy stays verbatim-only — quotes ARE
quotes; paraphrase-in-quotes is the model's mistake to flag, not
auto-promote.
Schema: verifier_method CHECK constraint expanded to include
'paraphrase'. New idempotent migration `_rebuild_providence_cache_paraphrase`
mirrors `_rebuild_providence_cache_ungrounded` (table rebuild via
BEGIN IMMEDIATE; no value translation needed). Probes existing CHECK
from sqlite_master and no-ops if already expanded.
Tests: 9 new in tests/test_verify.py — 4 trailing-citation strip
(quote+span variants, URL-only parenthetical, end-to-end STRICT
recovery), 4 paraphrase strategy (high-coverage promote, low-coverage
reject, mixed-method label, quote-strategy preservation). Default
suite still green: 326 passed, 1 skipped.
Burned the live Pikachu cache record (audit chain extended) so a
fresh `make query Q="who is pikachu?"` exercises the new verifier
end-to-end.
russell@unturf.com
10c1cba6e0