1st-level generative AI as applications that are directly based on X-to-Y models (foundation models that build a kind of operating system for downstream tasks) where X and Y can be text/code, image, segmented image, thermal image, speech/sound/music/song, avatar, depth, 3D, video, 4D (3D video, NeRF), IMU (Inertial Measurement Unit), amino acid sequences (AAS), 3D-protein structure, sentiment, emotions, gestures, etc., e.g.

and 2nd-level generative AI that builds some kind of middleware and allows to implement agents by simplifying the combination of LLM-based 1st-level generative AI with other tools via actions (like web search, semantic search [based on embeddings and vector databases like Pinecone, Chroma, Milvus, Faiss], source code generation [REPL], calls to math tools like Wolfram Alpha, etc.), by using special prompting techniques (like templates, Chain-of-Thought [COT], Self-Consistency, Self-Ask, Tree Of Thoughts, ReAct [Reason + Act], Graph of Thoughts) within action chains, e.g.

we currently (April/May/June 2023) see a 3rd-level of generative AI that implements agents that can solve complex tasks by the interaction of different LLMs in complex chains, e.g.

However, older publications like Cicero may also fall into this category of complex applications. Typically, these agent implementations are (currently) not built on top of the 2nd-level generative AI frameworks. But this is going to change.

Other, simpler applications that just allow semantic search over private documents with a locally hosted LLM and embedding generation, such as e.g. PrivateGPT which is based on LangChain and Llama (functionality similar to OpenAI’s ChatGPT-Retrieval plugin), may also be of interest in this context. And also applications that concentrate on the code generation ability of LLMs like GPT-Code-UI and OpenInterpreter, both open-source implementations of OpenAI’s ChatGPT Code Interpreter/AdvancedDataAnalysis (similar to Bard’s implicit code execution; an alternative to Code Interpreter is plugin Noteable), or smol-ai developer (that generates the complete source code from a markup description) should be noticed.
There is a nice overview of LLM Powered Autonomous Agents on GitHub.

The next level may then be governed by embodied LLMs and agents (like PaLM-E with E for Embodied).