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mathis-l

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At least when working with local MCP servers I solved this problem by wrapping the mcp tools inside an in-memory cache/store. Each tool output gets stored under a unique id and the id is returned with the tool output. The agent can then invoke other tools by passing the id instead of generating all the input. Adding attribute access made this pretty powerful (e.g. pass content under tool_return_xyz.some.data to tool A as parameter b). This saves token costs and is a lot faster. Granted, it only works for passing values between tools but I could imagine an additional tool to pipe stuff into the storage layer would solve this.

I’ve worked on a code base that was about 15 years old and had gone through many team changes. It was a tricky domain with lots of complicated business logic. When making changes to the code, the commit history was often the only way to figure out if certain behavior was intended and why it was implemented this way. Documentation about how the product should behave often lacked the level of detail. I was certainly always thankful when a dev that was long gone from the team had written commit messages that communicated the intent behind a change.

You might want to give Haystack a try (disclaimer: I work at deepset, the company behind Haystack).

Haystack allows you to pre-process your documents into smaller chunks, calculate embeddings and index them into a document store. You can wrap all of that in a modular pipeline if you want.

Next, you can query your documents using a retrieval pipeline.

Regarding document store selection: Replacing your document store is easy, so I would start with the most simple one, probably an InMemoryDocumentStore. When you want to move from experimentation to production, you‘ll want to tailor your selection to your use case. Here‘s a few things that I‘ve observed.

You don’t want to manage anything and are fine with SaaS -> Pinecone

You have a very large dataset (500M+ vectors) and you want something that you can run locally -> maybe Qdrant

You have meta data that you want to incorporate into your retrieval or you want to do hybrid search -> Opensearch/Elasticsearch

Regarding model selection:

We‘ve seen https://huggingface.co/sentence-transformers/multi-qa-distil... work well for a good semantic search baseline with fast indexing times. If you feel like the performance is lacking, you could look at the E5 models. What also works fairly well for us is a multi-step retrieval process where we retrieve ~100 documents with BM25 first and then use a cross-encoder to rank these by semantic relevance. Very fast indexing times are a benefit and you also don’t need a beefy vector db to store your documents. Latency at query time will be slightly higher though and you might need a GPU machine to run your query pipeline.

Retrieval in Haystack: https://docs.haystack.deepset.ai/docs/retriever

Cross-Encoder approach: https://docs.haystack.deepset.ai/docs/ranker

Blog Post with an end-to-end retrieval example: https://haystack.deepset.ai/blog/how-to-build-a-semantic-sea...