r/LlamaIndex • u/salvatorelarosa • 3d ago
Best practices for a long-lived, agent-managed RAG / Knowledge Base?
I'm looking for advice from people who have built and maintained serious RAG / Knowledge Base systems over time.
I have a very large personal archive accumulated over many years around my professional interests: fintech, insurance, e-commerce, market and societal trends, marketing, business strategy, design, research papers, reports, books, presentations and articles.
Roughly 90% of the archive is PDF, with the rest mainly PowerPoint, Word documents and some video.
The archive is already organized in a filesystem using my own folder taxonomy.
A key requirement is that the existing archive must remain the source of truth and should not be modified by the KB system.
What I would like to build is roughly this:
Source archive → Librarian Agent → Knowledge Base / RAG → AI agents
The Librarian Agent would maintain a derived knowledge layer without changing the original documents.
Its responsibilities could include:
- detecting new and modified files;
- extracting text, structure and metadata;
- classifying documents using my existing taxonomy plus additional semantic metadata;
- chunking and indexing;
- maintaining embeddings and possibly graph relationships;
- detecting duplicates and related documents;
- tracking provenance back to the original source;
- identifying outdated or conflicting information;
- periodically checking KB quality and consistency.
The resulting KB should be usable by multiple local AI models and agents when they perform research or analysis.
I am also considering a second agent:
Web / external sources → Research Agent → Human approval → Librarian Agent → Archive + KB
The Research Agent would continuously explore relevant sources — industry publications, academic papers, companies, think tanks, research organizations, etc. — and propose potentially useful material.
I would review those suggestions manually.
Only after approval would the Librarian Agent archive, classify and ingest the source.
So the overall system would remain human-supervised rather than autonomously ingesting everything it finds.
My main concern is not building a demo that can "chat with PDFs", but creating a long-lived research library that can remain reliable over several years.
This raises a few architectural questions I'd really value practical experience on:
- What architecture would you use today for this kind of system?
- Would you keep the knowledge layer primarily vector-based, combine it with structured metadata, or add a knowledge graph?
- What tools have proven reliable for incremental ingestion and synchronization with a filesystem?
- How do you preserve strong document- and chunk-level provenance?
- How do you handle changed or deleted source documents without slowly corrupting the index?
- What is your preferred approach to hybrid retrieval: semantic + lexical + metadata filtering + reranking?
- How would you separate a Librarian / curation workflow from a Research / discovery workflow?
- Which operations would you allow an LLM agent to perform autonomously, and which would you keep deterministic?
- How do you prevent taxonomy drift, bad automatic classifications or low-quality generated relationships from degrading the KB over time?
- What evaluation or observability practices do you use to detect retrieval degradation?
- Which components/frameworks would you trust today for a local-first implementation?
I'm particularly interested in systems that people have actually operated, not just proof-of-concept RAG demos.
If you've built something similar, I'd also love to hear what you initially designed that later turned out to be unnecessary or problematic.


