By low-level, it is with respect to the agent interface.
The original purpose is to help people understand how the inner agent framework is internally implemented, like those:
OpenAI Agents: https://github.com/openai/openai-agents-python/blob/48ff99bb... Pydantic Agents: https://github.com/pydantic/pydantic-ai/blob/4c0f384a0626299... Langchain: https://github.com/langchain-ai/langchain/blob/4d1d726e61ed5... LangGraph: https://github.com/langchain-ai/langgraph/blob/24f7d7c4399e2...