pgvector for CIOS Brain vector search over separate vector DB

Decision

Use pgvector extension on shared PostgreSQL (paperclip-postgres) for Brain embedding search

Rationale

PostgreSQL already deployed for Paperclip. pgvector avoids new infra, native SQL integration, ivfflat indexes sufficient for our scale.

Alternatives Rejected

  1. Qdrant
  2. Weaviate
  3. Milvus
  4. ChromaDB

Outcome

Pending