Optional ReadonlyallowedReadonlyarmsThe arms to compare (settings / plugin / pluginDir per arm).
ReadonlychecksOptional ReadonlyeffortReasoning budget for the run (claude --effort, e.g. "low" or an integer).
Lives here beside model because it is part of the MEASUREMENT — it moves the
output distribution, not the sample size — so it is hashed into the lock and
the cache, and never read from an env var. Omit for the harness default.
Optional ReadonlyfixtureOptional ReadonlymodelOptional ReadonlyspacingOptional ReadonlystubStub each arm's skill BODIES (frontmatter kept) before the run — the A/B
counterpart to MeasureSpec.stubSkillBodies. For firing comparisons
(does description variant A fire more than B?), every arm that sets
pluginDir / skillsDir is repackaged with bodies stripped so each run
stops at selection — a fraction of the tokens. Arms without one are left
untouched. Don't combine with judged/quality checks. See stubSkillBody.
ReadonlytaskOptional ReadonlytimeoutOptional Readonlytrials
A task scored against checks across NAMED arms (the harness variable on/off).