Knowledge bases

A knowledge base is an index of your content that your agents search: built by the engine, in your own account, from the sources you connect. LightHouse reports on its health with counts only; it never holds the content.

Where the index lives

The index is in your deployment, in your account: SQLite (with or without vectors), PostgreSQL (with or without pgvector) or OpenSearch. The documents it is built from are there too: each connector writes one Markdown file per item, with front matter, into the deployment’s own corpus. See Where everything lives.

Read in place, never copied

When a person opens content in LightHouse (Security and context → Content in place), the request goes to your deployment’s content reader, which dials out to LightHouse and answers only requests signed with Atlantic’s reader key. The content is shown and not kept. Reading it needs the content_viewer role. If your deployment cannot be reached, LightHouse says so (503 tier_b_unavailable) rather than showing an empty list.

Search

The engine’s retrieval is hybrid: keyword and meaning, fused by rank, with your access scope applied inside the query. It abstains, returning nothing, when no passage clears a calibrated floor, so an agent can say it found nothing rather than guess. Every search is measured: candidates considered, passages returned, tokens sent and tokens not sent. See Cost and token optimisation.

Freshness and re-indexing

Each connector keeps a cursor and reads only what changed since its last pull. A source is pulled on its own card’s schedule, not on a fixed clock. A changed item is rewritten; an unchanged one is left alone; an item deleted at the source is removed where the connector can tell (see each connector’s page).

Each deployment reports its knowledge bases’ health daily and whenever an index changes: documents, chunks and tokens; the last ingest and the last successful one; failures by class over 30 days; stale and undated documents against the pack’s freshness policy; the duplicate rate; and coverage by tag.

In LightHouse and the API

• Agents → Knowledge lists each knowledge base with its health.
• GET /api/v1/knowledge-bases and GET /api/v1/knowledge-bases/{index}: see the Read reference.
• MCP: knowledge_bases, knowledge_base, and knowledge (content, read in place, content_viewer).