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Agentic Spectrum
Agentic Spectrum

Agentic Spectrum

Tags
AI
Tech
Published
June 30, 2024
Author
Travis Fischer
notion image
 

Intro

AI agents are self-driving computer programs.
And just like self-driving cars, it’s useful to consider agents as a spectrum of autonomy: the agentic spectrum. Agents can be characterized along this spectrum by answering one simple question:
Who is deciding how to construct and traverse the execution graph of an AI agent?
The execution graph or control flow of a program is a graph of possible actions the program may take over time. Most computer programs today derive their execution graphs from source code written by one or more human programmers. This is a very deterministic and relatively easy to debug world, where even primitives such as random number utilities are pseudorandom and can be controlled deterministically via seeds.
Agents, on the other hand, use an AI model such as an LLM to decide the control flow of an application. The extent that the control flow of a program is determined ahead of time by a human programmer versus being dynamically determined by an LLM at runtime is the deciding factor in the level of autonomy of an AI agent.
 

Why is this important?

Reliability and generality are the two key factors holding back AI agents from more widespread adoption. By understanding the agentic spectrum, AI engineers and agentic authors can make better decisions on how to create more reliable agents today.
A question I ask myself a lot when thinking about different L5 agent demos is how these use cases could be reframed from the perspective of less autonomous yet more reliable L2/L3 agents.
 

Spectrum

  • L1 agents are traditional computer programs and deterministic workflows.
    • The execution graph is controlled by static code which is most often written by a human programmer.
    • L1 agents may invoke LLMs or other AI models, but they do not rely on these models to determine the program’s control flow.
    • L1 agents may be autonomous in that they don’t require user interaction at runtime (like a background workflow script), but they are not autonomous from the perspective of the human programmers who created them. E.g., the human programmer is still driving the bus.
  • L2 agents use LLMs selectively to decide how to handle key points in the program’s control flow.
    • Today, this often boils down to deciding which tool to invoke based on a set of tools which have been carefully curated by a human programmer.
    • The most common example of L2 agents today is invoking an LLM with access to tools in a while loop.
    • The majority of the program’s control flow still resides outside of the LLM’s purview and is controlled by a human programmer.
  • L3 agents are defined by an execution graph that is constructed statically by an expert human programmer which is handed off to an LLM to determine how to traverse this graph at runtime.
    • The defining characteristic of L3 agents is that they tend to be hierarchical or recursive in nature, but the entire execution graph has been carefully crafted by a human programmer ahead of time.
    • L3 agents are commonly composed of L1/L2 agents with some higher-order agent orchestrating the execution of these sub-agents.
  • L4 agents add some dynamic actions to the execution graph which are not known a priori by the human programmer.
    • The majority of the control flow may still controlled by code written by a human programmer, but for the first time, L4 agents introduce the ability for an LLM to create novel, dynamic actions at runtime.
    • If an agent creates and executes dynamic code at runtime, it is at least an L4 agent.
  • L5 agents are fully autonomous programs where the entire execution graph is constructed and traversed on-the-fly.
    • Examples of prototypical L5 agents include BabyAGI, AutoGPT, and MultiOn.
 

Insights

  • You can reduce L4/L5 agents to the dynamic construction of an execution graph plus the ability to execute that graph reliably – e.g., L3 agents.
  • L4 and L5 agents are really the only point at which cognitive architectures come into play.
  • Reliable, general L5 agents are functionally equivalent to AGI.
  • The same spectrum can be applied to embodied agents aka robots.
  • The L1-L5 levels of self-driving vehicle automation are a very useful analog when thinking about the agentic spectrum.
 

Further Reading

What is an AI agent?
Learn what AI agents are, how they work in an LLM loop, and where workflows fit so you can build reliable, production-ready autonomous systems.
What is an AI agent?
https://www.langchain.com/blog/what-is-an-agent
What is an AI agent?
LLM Powered Autonomous Agents
Building agents with LLM (large language model) as its core controller is a cool concept. Several proof-of-concepts demos, such as AutoGPT, GPT-Engineer and BabyAGI, serve as inspiring examples. The potentiality of LLM extends beyond generating well-written copies, stories, essays and programs; it can be framed as a powerful general problem solver. Agent System Overview In a LLM-powered autonomous agent system, LLM functions as the agent’s brain, complemented by several key components: Planning Subgoal and decomposition: The agent breaks down large tasks into smaller, manageable subgoals, enabling efficient handling of complex tasks. Reflection and refinement: The agent can do self-criticism and self-reflection over past actions, learn from mistakes and refine them for future steps, thereby improving the quality of final results. Memory Short-term memory: I would consider all the in-context learning (See Prompt Engineering) as utilizing short-term memory of the model to learn. Long-term memory: This provides the agent with the capability to retain and recall (infinite) information over extended periods, often by leveraging an external vector store and fast retrieval. Tool use The agent learns to call external APIs for extra information that is missing from the model weights (often hard to change after pre-training), including current information, code execution capability, access to proprietary information sources and more. Overview of a LLM-powered autonomous agent system. Component One: Planning A complicated task usually involves many steps. An agent needs to know what they are and plan ahead.
LLM Powered Autonomous Agents
https://lilianweng.github.io/posts/2023-06-23-agent/
An Army of Agents
An approachable introduction to AI agents and why they’re likely to be the most impactful technology of our generation.
An Army of Agents
https://transitivebullsh.it/ai-agents
 
Table of Contents
IntroWhy is this important?SpectrumInsightsFurther Reading
Copyright 2026 Travis Fischer