Two Levels of Agentic DesignPatterns in AgentsThe Single-Agent Loop: Minimalist AutonomyThe Planner–Executor–Reflector Pattern—“Think Ahead, then Execute.”Tool-Augmented Reasoning Agents = Embedded Reasoning + External ActionExample: ReAct + Tool Frameworks in PracticeExample of Tool-Augmented Reasoning with RAGDesign Topologies in Agentic Architectures—How Multiple Agents Are WiredSequential Example—Retail Support Agent PipelineExample of Hierarchical Topology—AI NewsletterExample of Hybrid Topology—Universal Enterprise AssistantPayroll: Structured Change Under GovernanceHealth: Policy-Driven PrecisionTech: Autonomous Service with GuardrailsController and Coordination LayerConcurrent/Parallel Multi-agent PatternChoosing Between Single Agent, PER, and Multi-agent ArchitecturesDecision Tree on Picking the Right Agentic PatternChallenges and ConsiderationsMake Tools Contract First—and Enforce the Contract Both WaysReduce Hallucination at the Two Choke Points: Tool Choice and ArgumentsPut Guardrails Outside the Model—Least Privilege, Action Limits, and ApprovalsRetries Should Be Purposeful: Classify, Back Off, and Avoid Duplicate Side EffectsBound the Loop and Budget; Detect “Infinite” or Unproductive IterationsTeach the Model to Reflect When StuckPrefer Smaller, Specialized Models and Selective Tool UseHarden Untrusted Input and BrowsingOperationalizing Guardrails and Scaling TogetherKey Takeaways
