Originally published on andrew.ooo — visit the original for any updates, code snippets that aged out, or follow-up posts. TL;DR CocoIndex is an open-source Python framework (with a Rust core) that solves the most underrated problem in production AI: your agent's RAG index goes stale the moment the data changes . Instead of rebuilding the whole vector store every hour, CocoIndex tracks per-row provenance and only reprocesses the delta when a source file, a chunking function, or an embedding model changes. It's trending hard on GitHub right now — +1,798 stars this week , ~9,700 total — and the framework has been pitched as "React for data engineering" because you declare the target state and the engine keeps it in sync forever.…