This section covers the basic data types and schemas that are used throughout the codebase.
When working with language models, the primary interface through which you can interact with them is through text. As an over simplification, a lot of models are "text in, text out". Therefor, a lot of the interfaces in LangChain are centered around text.
The primary interface through which end users interact with these is a chat interface. For this reason, some model providers even started providing access to the underlying API in a way that expects chat messages. These messages have a content field (which is usually text) and are associated with a user. Right now the supported users are System, Human, and AI.
Examples are input/output pairs that represent inputs to a function and then expected output. They can be used in both training and evaluation of models.
A piece of unstructured data. Consists of page_content (the content of the data) and metadata (auxiliary pieces of information describing attributes of the data).