fix(s31): close 2 review findings — drop description from the embedding + re-derive SC2 on the minted shape

This commit is contained in:
Kjell Tore Guttormsen 2026-07-25 12:31:06 +02:00
commit 969d450b31
3 changed files with 172 additions and 43 deletions

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@ -12,9 +12,15 @@ the D7 fault line. Three guards hold that line, each with a named detach point:
3. **No network** an AST sweep for network modules, since a real embeddings client is an
extension point and must never be smuggled into the offline default.
And one load-bearing behavioural seam (SC2): on a 500+ verdict base where two candidates are
structurally INDISTINGUISHABLE, the cosine term is the only thing that can separate them.
And one load-bearing behavioural seam (SC2): on a 500+ verdict base where two candidates TIE on
the structural score, the cosine term is the only thing that can separate them.
**Detach point: zero/remove the cosine term CORRECT no longer top-1.**
The pair ties on equal Jaccard over DIFFERENT code sets rather than by being structurally
identical, so both candidates are constructible through ``capture_verdict`` the path the
framework actually mints on. Plus one regression guard (defect P1): a framework-minted and an
externally-authored verdict that are structurally identical must embed identically, so the
system's own echo of the query can no longer outrank genuine expert prose.
"""
from __future__ import annotations
@ -24,13 +30,23 @@ import subprocess
import sys
from pathlib import Path
import numpy as np
from portfolio_optimiser.semretrieval import (
FakeEmbedder,
HybridRanker,
StructuralRetriever,
cosine,
)
from portfolio_optimiser.verdicts import ProposalFeatures, Verdict, VerdictStore, similarity
from portfolio_optimiser.verdicts import (
ProposalFeatures,
Verdict,
VerdictStore,
capture_verdict,
similarity,
verdict_from_dict,
verdict_to_dict,
)
_SEMRETRIEVAL = (
Path(__file__).resolve().parents[1] / "src" / "portfolio_optimiser" / "semretrieval.py"
@ -106,54 +122,69 @@ def test_semretrieval_imports_no_network_modules() -> None:
# --- SC2: the cosine term is load-bearing on a structurally tied 500+ base ---------------------
#
# The pair ties on the STRUCTURAL score while carrying DIFFERENT cost codes — equal Jaccard
# against the query (1/3 each), same measure, same magnitude bucket => similarity 0.6 == 0.6.
# That matters: the previous fixture tied by being structurally IDENTICAL and separated only by
# hand-written prose, a shape the framework cannot mint (``_mint_id`` ignores description, so
# both candidates would share one id and ``VerdictStore.add`` is first-write-wins). Differing in
# codes makes the pair genuinely constructible through ``capture_verdict`` — the real minting
# path — so the proof now runs on data the system can actually produce.
#
# Every feature set carries ``description == measure_type``, which is exactly what both live
# minting paths emit (``run._features_of`` sets ``description=proposal.measure``;
# ``verdicts._features_from_ir`` sets ``description=ir["measure"]``).
_TIED_CODES = frozenset({"05.2", "03.1"})
_MEASURE = "asfalt"
_QUERY_CODES = frozenset({"05.1", "05.2"})
_CORRECT_CODES = frozenset({"05.1", "07.4"})
_DISTRACTOR_CODES = frozenset({"05.2", "09.8"})
# CORRECT's id sorts AFTER the distractor's, so the structural ranking's `(-similarity, id)` key
# puts the DISTRACTOR first. Only the cosine term can overturn that. The id doubles as a unique
# grep marker: it appears nowhere else in the repo, so a stray match cannot fake a pass.
_CORRECT_ID = "zz-s31-cosine-tiebreak-4b7e"
_DISTRACTOR_ID = "aa-structural-tie-winner"
# Unique grep markers: these strings appear nowhere else in the repo, so a stray match cannot
# fake a pass. They ride in the RATIONALE (not the id) because ids are now minted content
# hashes — and because ``format_fewshot`` puts the rationale into the prompt, which is the
# channel the CLI-level proof downstream depends on.
_CORRECT_MARKER = "zz-s31-cosine-tiebreak-4b7e"
_DISTRACTOR_MARKER = "aa-structural-tie-winner"
_QUERY = ProposalFeatures(
affected_codes=_TIED_CODES,
measure_type="scope_reduction",
affected_codes=_QUERY_CODES,
measure_type=_MEASURE,
claimed_saving_nok=220_000.0,
description="reduce asphalt base course thickness on the school approach",
description=_MEASURE,
)
def _tied_verdict(verdict_id: str, description: str) -> Verdict:
"""Structurally IDENTICAL to the query — same codes, measure and magnitude bucket. Only the
(structurally ignored) description differs, which is exactly what makes these two candidates
inseparable without a semantic signal."""
return Verdict(
id=verdict_id,
proposal_features=ProposalFeatures(
affected_codes=_TIED_CODES,
measure_type="scope_reduction",
def _tied_verdict(codes: frozenset[str], decision: str, marker: str) -> Verdict:
"""Structurally TIED with the query — equal Jaccard, same measure, same magnitude bucket —
but on a different code set, so the canonical embedding string differs and cosine has
something to separate. Minted through ``capture_verdict``, never hand-assigned."""
return capture_verdict(
ProposalFeatures(
affected_codes=codes,
measure_type=_MEASURE,
claimed_saving_nok=200_000.0, # same bucket [100k, 500k) as the query
description=description,
description=_MEASURE,
),
decision="approved",
rationale=f"prior ruling reached via {verdict_id}",
decision,
f"prior ruling reached via {marker}",
)
# Minted ids, resolved once so the ordering property below is stated in terms of real values.
_CORRECT_ID = _tied_verdict(_CORRECT_CODES, "approved", _CORRECT_MARKER).id
_DISTRACTOR_ID = _tied_verdict(_DISTRACTOR_CODES, "rejected", _DISTRACTOR_MARKER).id
def _synthetic_base(n: int = 500) -> list[Verdict]:
"""Two structurally tied candidates plus ``n - 2`` strictly-lower-scoring fillers, so the
ranking has to hold up at a realistic base size rather than on a three-item toy store."""
correct = _tied_verdict(
_CORRECT_ID,
# Tuned, and admittedly so: a sha256 projection carries no inherent semantics, so this
# wording was selected because it lands nearer the query than the distractor does. The
# proof of the seam is the detach control below, not the plausibility of this string.
"shallower asphalt base layer along the school approach",
)
distractor = _tied_verdict(
_DISTRACTOR_ID,
"unrelated administrative rebate on office cleaning contract",
)
# Not tuned prose any more: the two candidates differ in their CODE SETS, and the cosine
# ordering over a sha256 projection is deterministic but semantically arbitrary. The proof of
# the seam is the detach control below — that removing the cosine term flips the ranking —
# never the plausibility of either candidate.
correct = _tied_verdict(_CORRECT_CODES, "approved", _CORRECT_MARKER)
distractor = _tied_verdict(_DISTRACTOR_CODES, "rejected", _DISTRACTOR_MARKER)
fillers = [
Verdict(
id=f"filler-{i:04d}",
@ -173,15 +204,32 @@ def _synthetic_base(n: int = 500) -> list[Verdict]:
def test_sc2_fixture_preconditions_hold() -> None:
"""The three properties the SC2 proof rests on, asserted rather than assumed: the pair is
structurally tied, CORRECT loses the id tie-break, and cosine favours CORRECT."""
"""Every property the SC2 proof rests on, asserted rather than assumed: the pair is
structurally tied on DIFFERENT code sets, both ids are minted by ``capture_verdict``, CORRECT
loses the id tie-break, and cosine favours CORRECT.
The code-set assertion is the one that keeps this fixture honest a pair that tied by being
structurally identical could not be minted at all, since ``_mint_id`` would collapse them onto
one id and the store would keep only the first."""
base = _synthetic_base()
correct = next(v for v in base if v.id == _CORRECT_ID)
distractor = next(v for v in base if v.id == _DISTRACTOR_ID)
# Tied structurally, but NOT structurally identical.
assert similarity(_QUERY, correct.proposal_features) == similarity(
_QUERY, distractor.proposal_features
)
assert correct.proposal_features.affected_codes != distractor.proposal_features.affected_codes
# The framework-minted shape: description carries the measure, on every feature set.
for features in (_QUERY, correct.proposal_features, distractor.proposal_features):
assert features.description == features.measure_type == _MEASURE
# Ids are content hashes of the features, not hand-written — re-minting reproduces them.
assert correct.id != distractor.id
assert correct.id == capture_verdict(correct.proposal_features, "approved", "re-mint").id
assert distractor.id == capture_verdict(distractor.proposal_features, "rejected", "re-mint").id
assert _DISTRACTOR_ID < _CORRECT_ID # structural id tie-break favours the distractor
embedder = FakeEmbedder()
@ -192,6 +240,56 @@ def test_sc2_fixture_preconditions_hold() -> None:
assert len(base) >= 500
def test_minted_and_authored_verdicts_embed_identically_on_a_structural_tie() -> None:
"""REGRESSION (defect P1) — a framework-minted verdict and an externally-authored one that
are structurally identical must now embed IDENTICALLY.
Before ``description`` left the embedding, the framework minted every feature set with
``description == measure`` while a human/persona verdict arrived through the inbox carrying
real prose. On a mixed store the system's own echo of the query scored ~1.0 and genuine expert
prose ~0.72, so the hybrid pushed real rulings BELOW the framework's restatement of its own
question the inverse of the feature's purpose, and the same self-contamination the Step-8
promotion gate exists to prevent.
Detach point: restore ``features.description`` to ``_canonical_feature_string`` RED."""
features = ProposalFeatures(
affected_codes=_CORRECT_CODES,
measure_type=_MEASURE,
claimed_saving_nok=200_000.0,
description=_MEASURE, # the shape run._features_of / _features_from_ir emit
)
minted = capture_verdict(features, "approved", "framework-captured ruling")
# The same proposal as an expert would file it: identical structure, human prose.
authored = verdict_from_dict(
{
**verdict_to_dict(minted),
"rationale": "the base course reduction was accepted on the school approach",
"proposal_features": {
**verdict_to_dict(minted)["proposal_features"],
"description": "shallower asphalt base layer along the school approach",
},
}
)
embedder = FakeEmbedder()
query_vector = embedder(_QUERY)
# The load-bearing claim: the two embed to the SAME vector, bit for bit.
assert np.array_equal(
embedder(minted.proposal_features), embedder(authored.proposal_features)
), "prose still leaks into the embedding — the framework's own echo can outrank expert text"
# ...and therefore rank identically. Compared at the ranking key's own tolerance, not on raw
# equality: ``np.dot`` over two separately allocated but bit-identical vectors can differ by
# one ulp, because the reduction path varies with buffer alignment. That is precisely why
# ``HybridRanker`` orders on ``(-round(score, 9), id)`` rather than the raw score — asserting
# bit-equality here would pin a property the system deliberately does not rely on.
assert round(cosine(query_vector, embedder(minted.proposal_features)), 9) == round(
cosine(query_vector, embedder(authored.proposal_features)), 9
)
def test_sc2_control_structural_ranking_puts_the_distractor_first() -> None:
"""CONTROL — without a semantic term the CORRECT verdict is unreachable. If this ever goes
green with CORRECT on top, the positive below proves nothing."""