It does look like it makes easier to code against a model. But, is this supposed to work along side lang-chain or hugging face agents or as an alternative to?
As others mentioned, this was initially developed before LangChain became widely used. Since it is lower level, you can leverage other tools, like any vector store interface you like such as in LangChain. Writing complex chain of thought structure is much more concise in guidance I think since it tries to keep you as close to the real strings going into the model as possible.
The first commit was on November 6th, but it didn't show up in Web Archive until May 6th, suggesting it was developed mostly in private and in parallel with LangChain (LangChain's first commit in Github is about October 24th). Microsoft's code is very tidy and organized. I wonder if they used this tool internally to support their LLM research efforts.
It's in langchain competitor territory but also much lower level and less opinionated.
I.e. Guidance has no vector store support but it does manage caching Key/Value on the GPU which can be a big latency win