The right enterprise playbook for an agent incident in 2026 has six steps that do not appear in any standard SRE handbook — action-class containment before root-cause analysis, reasoning-trace forensics, blast-radius reconstruction across downstream agents and systems, stakeholder notification with the specific failure mode named, regulatory exposure assessment for in-scope deployments, and selective re-enable with degraded-mode guardrails — and CIOs without this playbook will spend their first agent incident discovering it under crisis conditions.

60-day cadence covers the first round of major-vendor incident-response disclosure updates and any regulatory enforcement actions referencing inadequate agent IR.