Mutation testing on a third directory, and a worse score

A technique applied to a third directory, with a score of thirty-eight per cent and a good reason.

  src/Domain/Pricing   2023   71% → 88%
  src/Domain/Tax       2025   41% → 79%
  src/Http/Resources   2026   38%

the resources are serialisers: they map an object to an
array. a mutant that changes a key's value survives
because the tests assert on the SHAPE rather than on
the values.

which is what the contract tests assert, deliberately —
the values come from the domain, which is tested
elsewhere.

no action. the score is measuring the wrong thing here.

A low score on code whose correctness is asserted at a different level is a false signal, and the tool has no way to know. Recording that conclusion is what stops the next person running it and opening a ticket — the alternative is a metric that produces work rather than information.