Multi-Agent Layer and Design Multi-Agent Design Use role-based agents instead of one omnipotent agent. Agent Responsibility Planner Break down tasks Researcher Retrieval Executor Tool use Verifier Check outputs Safety Agent Policy checks Finance Agent Budget controls Audit Agent Logging Orchestration Patterns ●       Manager-worker — a coordinator agent dispatches to specialist workers and merges results. ●  Task graph / stateful graph orchestration — the workflow is modeled as a directed (often cyclic) graph with conditional branching, persistent checkpoints, and interruptible human-in-the-loop points, rather than a fixed linear chain. ●       Shared memory store — agents coordinate through a common memory layer instead of direct message passing. Open problem: Byzantine fault tolerance in adversarial multi-agent settings remains an unresolved research area — don't assume agent-reported results are trustworthy without independent verification in high-stakes settings. Model Routing / Cost Optimization Use the cheapest model that can reliably complete the task. Tasks Model Tier Classification Small Summaries Small / Medium Planning Medium / Large Coding Specialist Verification Large Legal / Compliance Premium deterministic Principle: Intelligence should scale with difficulty. Many current model families additionally expose configurable reasoning effort as a routing dimension in its own right — treat effort level as a tunable dimension alongside model size. Reflection / Critique Loops Use secondary reasoning for high-stakes decisions. Trigger Conditions ●       Low confidence ●       High risk ●       Contradictory evidence ●       Large transaction ●       Compliance-sensitive request Reflection Flow Human-in-the-Loop Design Humans should be inserted intelligently. Human Role Tasks Reviewer High-risk decisions Supervisor Real-time override Trainer Correct outputs Auditor Compliance review Confidence Handoff: Escalate when confidence < 0.85–0.90   Recommended use  What to Use When Scenario When to use Highest transparency ReAct + logs Fastest cheap execution Small model routing Complex workflows Multi-agent workflow / task graph Safety critical Verifier + human gate Large enterprise memory Graph + Vector memory Heavy integrations MCP tool ecosystem Packaged reusable know-how Skills layer (New) High trust requirements Policy-first architecture Corpus fits in context window Load-and-ask, skip the retrieval pipeline (New)