Task 1.3. An expected row may carry a family label, stored opaquely because the
classifier owns the taxonomy and the corpus module never imports the learning
package. Every pair carries a computed reason when it cannot be scored: a
declared known limit wins, otherwise identical twin when the two excerpts are
the same code once the provenance header is stripped. No row is ever dropped.
Two corpus defects the new accounting surfaces, committed as an artifact beside
the numbers they cap. Nineteen repositories sit on both sides of the split, so a
learning path could be taught by one file of a repository and evaluated on
another. Ten groups of pairs share a vulnerable excerpt byte for byte, mostly
the same fix harvested twice at different granularity.
The split helper keeps every declared split, lets rows that named none inherit
their repository's side, and otherwise assigns a whole repository at once,
oldest first, so nothing straddles by our doing. Pair signals can now be
restricted to one split, which is what lets a learning path teach from train
rows only.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
Measured 2026-09-06 on the vibe-py holdout: the existing tool hunter, with no
learning, scores 12/14 pair-correct (Youden +0.857, no leaks) once detection
and silence are keyed on the labeled class and function and the byte-identical
twins are excluded; the overlay scores 5/14 on the same rows. The published
hunter number (0/17, Youden -0.588) was a scoring artifact: the scorer wanted
the literal CWE id in the finding text and the prompt never asked for it.
The brief proposes an auto-classifier as the routing key, one evolved hunter
configuration per class, a class-aware scorer with unscorable denominators,
the split enforced by construction, and the HarnessX evolve loop with per-class
attribution as the round primitive. Raw measurements are committed under
reports/measurements.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
