Get a layered explanation of pasted code: purpose, execution walkthrough, hidden gotchas, and a map of what is safe to change.
Produces a behavior-first test plan and then real unit tests covering happy paths, boundaries, error paths, and every visible branch.
A code review that separates bugs, latent risks, and clarity problems, cites specific lines, and ends with a merge verdict.
Turns debugging into a checkable loop: facts, ranked hypotheses, and the single cheapest probe that separates them.
Refactors code through an explicit contract inventory, stepwise plan, and verification list — without changing observable behavior.
A structured trade-off analysis against your stated priorities, the strongest case against each option, and a committable ADR.
Builds a safety net around untested legacy code: dependency audit, minimal seams, behavior-pinning tests, and a go/no-go checklist.
For bugs that will not reproduce: candidate failure mechanisms, an instrumentation plan, and falsifiable predictions for the next occurrence.