Maintainer decision "Neutralise both for v1".
1. Phantom candidates. A pair side's candidates are now only the functions that
side declares (plane/harvest.py `declares`, the excerpt builder's
function_bounds); a labelled function absent from a side is listed under
`absent_on_side` and never asked, and a side declaring none of its verify
family's functions is no verify unit. The recorded harvest units held 58
phantom verify candidates (53 fixed, 5 vulnerable sides). build_features.py
skips label rows whose side does not declare the function and drops their
earlier rows (MemoryStore.drop_rows); rebuilt the pair records from the
recorded signals, no model call: 126 label rows absent_on_side (117 fixed,
9 vulnerable) -- access_control 13, config_secrets 4, deserialization 20,
injection 28, memory 4, output_encoding 16, path 15, untrusted_destination
26 -- so 252 feature rows dropped (1712 -> 1460); no other row changed.
2. Engine withheld. Input profiles in learn/schema.py (`v1` withholds the
engine instrument, `full` withholds nothing); ProgramSpec.inputs defaults to
v1 and compile.toml records it. Neither the engine's state nor its values
reach the candidate, examples, demonstrations or the instruction proposer's
error summary, and the Gower retrieval distance leaves the engine block out.
Stored records are unchanged. design.md Risks records the decision and that
the engine returns only through a pre-registered A/B on assumed-benign and
benign-control negatives.
3. `ousast learn audit-leaks` (learn/leaks.py): per feature and per instrument
state, separation = (pairs the signal alone puts on the right side - on the
wrong side) / pairs, over all pairs and per family; flagged at >= 0.20 over
>= 10 pairs. Counts under
benchmarks/measurements/2026-10-01-decision-engine-leak-audit/ (before and
after the rebuild). After: facts.function_lines (0.80 untrusted_destination,
0.75 config_secrets, 0.26 injection; higher on fixed), verify.turns_mean
0.67 config_secrets, eng.* 0.35-0.40 output_encoding, verify.flag_a/votes/
site_offset and agree.final 0.20-0.30 on 10-12 pair families. Before the
rebuild the phantom fixed sides drove state.source/state.roles/ms.flagged
to 1.0 and state.engine to 0.95 on deserialization.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
learn/retrieve.py: stage 1 is a per-instrument Gower distance over the
profile's allow-listed features with explicit missing (both ran: mean
feature distance; differing states 1; same non-ran state 0; null in one 1;
priors dropped with priors=off), n1 = 40 with seeded tie-breaks; stage 2
re-ranks by r = lam(1 - D) + (1 - lam)cos, signals_only without the
target's vector; the balance rule takes k_ret = 6 (<= k/2 per label, <= 2
per group, <= 2 other families; `short` recorded). eligible() is the only
way into a prompt: not the target's group, not an evaluated group, not the
held-out source or framework, and outside deployment not a near-duplicate
(cos >= 0.98). assert_boundary repeats the check on rendered ids;
demonstrations of a held-out framework swap to their alternates;
deployment_fold excludes a scanned repository that is a corpus group;
seed_memory never hands a case its own group.
learn/folds.py: compile split (25% of groups per primary family, 60/40
boot/val), outer grouped 5-fold stratified by family and label mix,
leave-one-source-out, leave-one-framework-out (insufficient data below 10
groups), assert_disjoint and a folds digest; all seeded.
Tests: test_learn_retrieve.py (hand-computed Gower, lam 0/0.5, balance,
near-duplicates, test_boundary over outer/LOSO/LOFO folds with
demonstrations), test_learn_folds.py.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
