The outer loop vs. the inner loop of agents. A simple mental model to evolve the agent stack quickly and push to production faster.

Understanding the Outer Loop vs. Inner Loop in Agent Architectures: A Framework for Accelerated Development and Deployment

In recent experience deploying a multi-agent system for a Fortune 500 client, an essential insight emerged that significantly enhanced our development velocity: the clear separation of the outer loop and inner loop within our agent architecture. This conceptual distinction proved invaluable for streamlining workflows, facilitating rapid iteration, and delivering solutions to production more efficiently.

The Inner Loop: The Core of Agent Execution

The inner loop represents the control cycle of an individual agent responsible for executing specific tasks. At its core, the inner loop manages the process whereby the agent receives a particular assignment—be it human-initiated or autonomous—and proceeds to complete it with the assistance of a Large Language Model (LLM).

This cycle encompasses:

• Task Interpretation: Understanding the specific objectives assigned to the agent.
• Tool Utilization: Interacting with a defined set of tools or APIs exposed to the LLM to perform subtasks.
• System Prompts & State Management: Leveraging system prompts to steer the LLM’s behavior and managing checkpoints or context states to maintain consistency across iterations.

Within this inner loop, developers focus on ensuring robustness through features like idempotency—preventing duplicate operations—and implementing compensating actions for failure scenarios (e.g., if a tool fails, determining how to rollback or adjust). Incorporating workflow engines such as Temporal has proven highly effective here, providing reliable orchestration of complex, stateful processes without the need to build custom solutions from scratch.

The Outer Loop: Coordinating Multiple Agents

In contrast, the outer loop oversees the orchestration of multiple agents, dictating how work is routed, scheduled, and coordinated across the system. This layer operates at a higher level of granularity, focusing on:

• Work Dispatching: Assigning tasks to appropriate agents based on context or workload.
• Workflow Planning: Designing overarching workflows or missions that involve multiple agents or subprocesses.
• Inter-Agent Communication: Facilitating high-level coordination to achieve complex objectives.

The outer loop is less about detailed task execution and more about macro-level orchestration, akin to functioning as a proxy or conductor rather than a detailed executor. For this purpose, modern proxy infrastructure like Arch has proven invaluable, providing flexible, scalable