Use when designing a test plan for a distributed or stateful system — anything with persistence, replication, consensus, retries, idempotency, async messaging, multi-tenancy, or partial failure. Plans are claim-driven; investigate the product's claimed guarantees first, then design hypotheses and scenarios that try to falsify those claims under fault. Handles both change-scoped plans (a specific commit / PR / feature) and project-wide plans (a holistic plan for the whole system with existing-test inventory and gap analysis). Also use when asked to write a stability plan, fault matrix, release-validation plan, durability test plan, partition test plan, upgrade test plan, crash-recovery test plan, linearizability test plan, deterministic-simulation plan, tenant isolation test plan, authz / boundary test plan, namespace isolation plan, multi-protocol access plan, fairness test plan, noisy-neighbor test plan, "test plan to enough coverage", "what should we be testing", or "make a holistic test plan". Trigger even
Use when running a previously designed distributed-systems test plan against a real or simulated cluster — driving fault injection, workload, chaos scenarios, linearizability / consistency runs, durability tests, partition tests, crash-recovery tests, upgrade tests, performance/SLO runs, tenant isolation runs, boundary or authz runs, fairness / noisy-neighbor runs, or release validation. Also use when asked to "execute the plan", "reproduce a distributed bug", "run stability tests", "drive chaos", "validate a release end-to-end", "run the tenant isolation tests", "check fairness across tenants", or when a plan file exists at docs/testing-plans/ or any caller-specified location and needs to be run. Discovers the SUT's existing test toolbox (tools/, scripts/, runbooks) and uses it rather than reinventing, captures nemesis landing evidence per scenario, runs the green-but-broken and weak-oracle audits before any PASS, and (for boundary or fairness scenarios with §7.M.S arms in the plan) runs each surface arm sep