Recent advances in large language models (LLMs) have accelerated the adoption of AI across industries, yet single-model, monolithic architectures remain limited in domain specialization, workflow flexibility, and governance. This paper proposes a mult...
Recent advances in large language models (LLMs) have accelerated the adoption of AI across industries, yet single-model, monolithic architectures remain limited in domain specialization, workflow flexibility, and governance. This paper proposes a multi-agent architecture that integrates Retrieval-Augmented Generation (RAG) with two complementary open protocols—Model-Context-Protocol (MCP) for vertical integration with tools and data, and Agent-to-Agent (A2A) for horizontal collaboration among heterogeneous agents. We frame A2A messages as governance contract units, specifying a standard envelope-payload schema with policy identifiers, traceability metadata, and HMAC-SHA256 signatures to ensure integrity, accountability, and auditability. Building on policy-as-code, we detail a Rego-based policy deployment pipeline (approval → translation → test → release → enforcement) and an incident response feedback loop (detect, contain, analyze, remedy, learn) that operationalizes continuous improvement. We further present an observability stack—Prometheus, Grafana, Fluentd/OpenSearch (or Loki), and Jaeger/Zipkin/OpenTelemetry Collector—along with a governance dashboard that surfaces real-time policy violations, high-risk agents, policy deployment latency, and audit-log delays. To ground the framework, we provide domain scenarios in finance, healthcare, and manufacturing, and define evaluation metrics for governance effectiveness, including MTTD, MTTR, RCA accuracy, compliance alignment, and training coverage. Our contributions are threefold: (1) a unified reference architecture that composes MCP and A2A for secure, extensible multi-agent systems; (2) a contract-centric messaging model and policy-as-code pipeline that embed governance into runtime; and (3) a measurement-driven operations blueprint for observability, incident response, and continuous compliance. The results indicate that coupling standardized protocols with enforceable policies and actionable metrics enables scalable automation without sacrificing security, transparency, or regulatory alignment.