Postmortem: How a LangGraph 0.1 Multi-Agent Bug Broke Our 2026 Customer Support Bot Executive Summary On October 12, 2026, our production customer support bot experienced a 4-hour partial outage caused by an unpatched edge case in LangGraph 0.1’s multi-agent orchestration layer. The bug triggered infinite agent handoff loops for 18% of inbound customer queries, leading to SLA breaches, elevated ticket volume, and temporary loss of trust from enterprise clients. This postmortem details the incident timeline, root cause, resolution, and long-term prevention measures. Incident Timeline (UTC) 08:12 – First alert triggered: 200% spike in agent handoff latency detected by Datadog monitor. 08:19 – On-call engineers confirm 12% of support bot sessions are stuck in infinite loops, returning 504 Gateway Timeout errors to users. 08:32 – Incident declared SEV-2; war room opened with engineering, product, and support leads.…