Mutation Testing

Run the requested scope, or start with the changed files. A full-project run is appropriate when requested; mutation testing is not a default release requirement.

rtk proxy cargo mutants --no-shuffle -f src/config.rs
rtk proxy cargo mutants --no-shuffle -F 'function_name'

Use cargo mutants --help for installed options and job limits. Inspect the actual run output and mutants.out/missed.txt to distinguish outcomes:

Result	Interpretation
caught	Tests detected the mutation
missed	Tests did not detect it; inspect reachability and observable behavior
unviable	The mutated program did not compile
timeout	Execution exceeded its limit; investigate before assigning a cause

Prioritize changed business behavior and actionable gaps. Existing misses may be relevant to the requested scope; do not dismiss CLI or output behavior solely by filename. Some surviving mutations preserve behavior or cannot be meaningfully exercised, so zero missed mutants is not a universal completion criterion.

For diagnosis, report actionable misses and unresolved cases with evidence. When test improvements are requested, add assertions for observable behavior, run the affected tests, and rerun the relevant mutations. Complete with caught/missed/ unviable/timeout results for the tested scope and explain remaining limitations.