QMD
A small local search engine by Tobi Lütke (the Shopify founder) for your markdown notes: BM25 for exact search, vectors for semantics, LLM reranking to sort, all running on your machine with nothing leaving it. It is the 'retrieve' brick second brains on Obsidian are missing: accumulating is not retrieving, QMD fixes exactly that. Slots into an LLM wiki stack alongside Graphify, which handles the links between notes.
Strengths
- Three search stages (BM25 + vectors + LLM reranking) in one local binary
- Nothing leaves your machine: compatible with a vault holding confidential content
- Integrates naturally with an agent: search becomes a tool Claude calls
Limitations
- Terminal tool first: no native GUI, the Obsidian plugin is community-made
- Tobi Lütke's personal project: maintained at its author's pace, not a product team's
Best for
- An Obsidian vault of several hundred notes where native search no longer cuts it
- A memory agent that must load the right note without ingesting the whole vault