# kb-query

FastAPI search API in front of the module-5 KB retrieval engine
(`packages/kb-retrieval/`). Runs on **PIHA**, bound to PIHA's LAN IP only
(`exposure: private`, same class as paperless/nextcloud — no public ingress
yet). This is a **search API, not chat**: no answer synthesis over results,
that's phase 5.

## Endpoints

| Endpoint | Method | Purpose |
|---|---|---|
| `/healthz` | GET | `{"status": "ok", "sol_status": "up"\|"down"}` — `sol_status` is a live probe of Ollama@SOLARIA, no auth required (monitoring must reach it) |
| `/search?q=<text>&mode=cascade\|flat` | GET | `query_text -> embed -> cascade_query/flat_query -> results`, `mode` defaults to `cascade` |

`/search` response shape (module 5 phase 4 plan §4):

```json
{
  "query": "...", "mode": "cascade", "sol_status": "up",
  "results": [
    {"envelope_id": "paperless:119", "source": "paperless", "dist": 0.34,
     "chunk_index": 2, "text": "...", "link": "https://paper.kapala.org/documents/119/details"},
    {"envelope_id": "<Message-ID>", "source": "gmail", "dist": 0.44,
     "chunk_index": 0, "text": "...", "subject": "...", "from": "...", "date": "...",
     "link": null, "mail_ui_url": null}
  ]
}
```

`dist` is never filtered server-side — the 0.45/0.55 colour thresholds are a
frontend concern (a later step), not an API contract.

## Embed path (current step)

Calls Ollama on SOLARIA directly per request — no cache, no circuit breaker,
no local-PIHA fallback yet (that state machine, plan §2 decision 2/§5, is a
separate later step). If SOLARIA is unreachable, `/search` returns **503**;
`/healthz` still answers (`sol_status: "down"`), same tolerance pattern as
`llm-gateway`.

## Startup invariant (hard-fail)

At startup, kb-query queries `document_chunk.model` and
`document_summary.embedding_model` for the set of models behind *active*
embeddings, and refuses to start (crash-loop, visible via container restarts)
if the configured `EMBED_MODEL` (default `bge-m3`) isn't in both sets. This
guards against querying with an embedding space that doesn't match what's
actually indexed — see `app/startup.py` for why the check reads
`document_summary.embedding_model` and not `.model` (the latter is the LLM
that *wrote* the summary, e.g. `claude-haiku-4-5`, not the embedder).

## Configuration

`.env` — **gitignored**, copy from `env.example`. Required: `LAN_BIND_IP`,
`KB_DSN`. Optional: `OLLAMA_URL`, `EMBED_MODEL`, `SUMMARY_MODEL`.

## Deploy (PIHA)

1. `git pull` on PIHA (`~/homelab-codex-ws`).
2. `cp services/kb-query/env.example services/kb-query/.env` and fill in the
   real `KB_DSN` password.
3. ```
   docker compose -f services/kb-query/docker-compose.yml \
     -f hosts/piha/runtime/kb-query/docker-compose.override.yml up -d --build
   ```
4. Verify: `services/kb-query/healthcheck.sh`, then from PIHA:
   `curl "http://192.168.31.5:8230/search?q=test"`.

## Tests

```
pip install -e packages/kb-retrieval/
cd services/kb-query && pytest
```

Unit tests mock the DB connection and Ollama HTTP session (no live DB/Ollama
required) — same style as `packages/kb-retrieval/tests/`.

## Out of scope for this step

- Local-PIHA embed fallback / circuit breaker (plan §2 decision 2, §5).
- npm@PIHA vhost, OIDC login, DNS (plan §8) — `kb.kapala.org` is not wired up
  yet; reach the API directly over LAN/Tailscale for now.
- Frontend (plan §7) — `/search` returns bare JSON.