Known-failure mutation corpus

ZapTrace benchmarks include a known-failure mutation corpus. The corpus proves that checks catch realistic negative cases instead of only proving that clean examples pass.

Mutation classes

The initial corpus implements three mutation classes:

remove-decoupling
narrow-high-current-trace
remove-return-path

API

from zaptrace.benchmark.mutations import run_known_failure_mutation_corpus

report = run_known_failure_mutation_corpus(design)

The report includes:

schema_version
mutation_count
caught_count
missed_count
passed
results[]

Each result records:

mutation_id
mutation_class
expected_detector
caught
detail

Expected detectors

remove-decoupling          -> sipi-risk.decoupling
narrow-high-current-trace  -> current-density.violation
remove-return-path         -> sipi-risk.return-path

Release policy

Known-failure benchmark reports should fail when missed_count > 0. A missed known-failure means the engine produced or accepted a realistic bad design without the expected evidence gate firing.

Non-claims

Mutation corpus pass is regression evidence only. It does not replace full ERC, DRC, KiCad oracle checks, manufacturing export checks, or human review.