The verifier, not the artefact, observes the effect: SQL, path, command and SSRF
oracles owned by the verifier (XSS needs a browser executor, else no_oracle);
artefact exit code and output ignored; immutable checkout and dependencies;
3 runs per side; one-sided build or readiness failure is inconclusive. An
isolation failure raises IsolationUnavailable instead of reading as
could_not_build (the NPROC limit now applies inside the user namespace).
35 tests, including gaming attempts and 300 host processes.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
