AI Agent Architecture Evolution: From Single Agent to Production Hybrid
Phase 1: Single Agent
Days 1–90
All Tickets
Single
Agent
KB + CRM + Ticketing
51% resolution
30min → seconds
Phase 2: Sequential
Months 4–6
Classify
Account
Agent
Dispute
Agent
Resolve
68% resolution
Phase 3: Parallel
Months 7–9
◆
Regulatory
Risk
History
◆
Aggregate
60% faster
4s vs 12s sequential
Phase 4: Hierarchical
Months 10–12
Supervisor
Account
Payment
Credit
Synthesize
80–90% resolution
Phase 5: Production Hybrid
Production Maturity
Sequential
Routing
Parallel
Assessment
Hierarchical
Orchestration
Evaluator
QA Loop
Deterministic Guardrails
BPMN + Audit Trail
Three-Return Contract
results + next_task + reasoning
"Start simple, measure everything, add complexity only when it delivers measurable value." — Anthropic, Building Effective AI Agents (2025)