Define success metrics and guardrails for B2B chat

Define a rigorous success-measurement plan for the new EU business-to-customer chat subscription. Specify: (a) 5 primary KPIs that capture early product-market fit and monetization (e.g., Monthly Subscribed Companies, Monthly Subscription Revenue, Resolved-Within-24h Rate, First-Response-Time P50/P90, Net Revenue Retention), (b) 6 guardrails that prevent customer harm or spam (e.g., %Chats Not Solved, Long-Duration Chat Rate, Unexpected Message Burst Rate, Complaint Rate, Unsubscribe/Opt-out Rate, Negative Sentiment Share), and (c) exact operational definitions with formulas, event filters, and attribution rules (multi-language, bot vs human handoff, multi-agent threads, reopened tickets). For “Not Solved,” provide two measurable definitions: one using a sentiment model threshold and one using post-chat CSAT; discuss bias and failure modes for each and how you would calibrate thresholds. Include time windows (e.g., MoM, 28-day rolling), cohorting (by business signup month and by customer first-contact month), segmentation (country, vertical, company size), and data-quality checks (outliers, duplicate threads, late events). Propose target ranges and escalation triggers for each KPI/guardrail.