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What is little big brain?

little big brain (lbb) is an object-storage-native temporal graph and hybrid-search engine for AI context, written in Rust. It stores graph facts as append-only events, builds search indexes as disposable object-backed accelerators, and runs semantic hybrid search across BM25, vector, ontology, and graph-neighborhood signals — all over the same consistent snapshot.

It is designed to be the retrieval and memory layer behind AI applications and agents: durable enough to be the source of truth, and rich enough to answer lexical, semantic, and graph-shaped questions from one place.

  • Hybrid search that actually fuses signals. Lexical matching, BM25, vectors/ANN, ontology resolution, and graph-neighborhood traversal are combined and ranked together — with filters, facets, and reciprocal-rank fusion — not bolted on as separate systems.
  • A temporal knowledge graph. Facts are append-only observations with provenance and evidence. You can read current state, relationship history, and why a fact exists, and pin any query to a historical snapshot.
  • Standards-based query. A conformant SPARQL 1.1 engine, a structured SELECT/aggregate surface, and SHACL Core / SHACL-SPARQL / SHACL-AF validation and inference run over the same object-storage substrate.
  • Reasoning that derives what you didn’t write. RDFS type closure and SHACL-AF rule inference fold into ordinary queries — deterministic, transparent, and pinnable to a snapshot. See reasoning.
  • Object storage as the source of truth. The durable graph, WAL, and index runs live in object storage (local filesystem or S3-compatible). Compute is stateless and disposable; indexes are derived acceleration structures.
Surface Best for
TypeScript SDK (@lbb/client) Node, browser, and edge apps
Python SDK (lbb) Scripts, notebooks, data/ML workflows
MCP server (@lbb/mcp) Giving an AI agent a graph-aware tool belt
HTTP API Any language; also the native SPARQL 1.1 Protocol
Console Visual exploration, query, indexing, and operations
CLI Operating a self-hosted deployment (coming with self-hosting)

All of the application SDKs speak the same HTTP API and authenticate with the same stack API key, so you can mix them freely — write with Python, retrieve from TypeScript, let an agent read through MCP, and explore in the console, all against one graph.

Today little big brain is a hosted product: a managed data plane at db.eu.littlebigbrain.com, an account/stack API at api.littlebigbrain.com, a hosted MCP endpoint at mcp.littlebigbrain.com, and the console at cloud.littlebigbrain.com. You sign up, create a stack (an isolated tenant), and get a per-stack API key.

A self-hostable distribution — a Docker container / pre-built server that runs against a local filesystem or an S3-compatible bucket, with the CLI for operations — is on the roadmap.