# Product

Brain keeps a sourced history of the messages, documents, events, and records behind your product.
For each request, it returns the material that applies, where it came from, and what remains
uncertain.

## How Brain works

1. **Keep the record.** Save source material with the time it was recorded and where it came from.
2. **Track the change.** Derive relationships and versions without erasing the source.
3. **Leave decisions with your app.** Keep application-approved Objects separate from derived
   Memories.
4. **Return the evidence.** Return the records a request may use, with citations, gaps, conflicts,
   and cost.

## Built to be inspected

Cloud Run serves one API. Cloud SQL Postgres with pgvector stores Records, Memories, Objects, and
embeddings. Vertex AI derives and ranks. Sources, time, and application decisions remain visible
in the result.

BigQuery can be an upstream source of structured rows, but a managed BigQuery connector is not
shipped. Model and embedding upgrades are tested before they replace the current runtime.

## Source, finding, decision, result

1. **Source:** Records preserve content, stable customer IDs, metadata, and source time.
2. **Finding:** versioned Memories retain citations; Objects carry facts the application accepts.
3. **Result:** Context returns the evidence a request may use and names what remains unknown.

Your warehouse and application remain authoritative for operational data. The customer SpineStore
is live behind issued keys; the public sandbox is disposable.