[antti909]

Haystack has been around for a while now, and we've been mostly specializing in the extractive QA. The focus has been indeed on making the use of local Transformer models most easy and convenient for a backend application builder. You can build very reliable and sometimes quite elaborate NLP pipelines with Haystack (e.g., extractive or generative QA, summarization, document similarity, semantic search, FAQ-style search, etc. etc.) with either Transformer models, LLMs, or both. With the Agents you can also put an Agent on top of your pipelines and use a prompt-defined control to find the best underlying tool and pipeline for the task. Haystack has always included all the necessary 'infrastructure' components - pre-processing, indexing, several document stores to choose from (ES/OS, Pinecone, Weavite, Milvus, now Qdrant, etc.) and the means to evaluate and fine-tune Transformer models.

[d4rkp4ttern]

Thanks for clarifying. The support for local LLMs seems very interesting — would a haystack agent call out to a separately “running” self-hosted LLM via an API (REST, etc) or would it need to actually load up the model and directly query it (e.g model.generate(<prompt>) ) ?

Also it seems like the functionality of haystack subsumes those of langchain and llama-index (fka GPT-index) ?

[tholor]

Haystack Agents are designed in a way so that you can easily use them with different LLM providers. You just need to implement one standardized wrapper class for your modelprovider of choice (https://github.com/deepset-ai/haystack/blob/7c5f9313ff5eedf2...)

So back to your question: We will enable both ways in Haystack: 1) Loading a local model directly via Haystack AND 2) quering self-hosted models via REST (e.g. Huggingface running on AWS SageMaker). Our philosophy here: The model provider should be independent from your application logic and easy to switch.

In the current version, we support for local models only option 1. This works for many of the provided models provided by HuggingFace, e.g. flan-t5. We are already working on adding support for more open-source models (e.g. alpaca) as models like Flan-T5 don't perform great when used in Agents. The support for sagemaker endpoints is also on our list. Any options you'd like to see here?

[antti909]

To be precise - I don't think I'm saying 'local LLMs' above :) But technically possible, I guess, just hasn't been part of what's officially available. (There are also licensing issues still.) To answer your question about the APIs - the Agent itself queries OpenAI via REST to break the prompt down into tasks, then works with the underlying tools/pipelines using Python API (and then, e.g., a Transformer model that's part of the pipeline has to be 'loaded' into a GPU). Part of those pipelines might be using Promptnode (that can work with hosted LLMs via REST, but could also work with a local LLM). Re 'subsume' - well, that depends :) But arguably, you can build an NLP Python backend with Haystack only, of course.. Regardless of how complex your underlying use case is, or whether it's extractive, generative or both.