yau-plant-assistant/spec/REBUILD.md

# Rebuild from zero

> The full deployment runbook, moved out of `README.md` so that file can stay an
> orientation document. Nine phases, in order, each with a gate. Design detail for
> every phase is in [`BUILD-AI-CONTAINERS.md`](BUILD-AI-CONTAINERS.md); the host it
> deploys onto is described in [`YAU_Linux_Host_Onboarding.md`](YAU_Linux_Host_Onboarding.md),
> which **wins wherever the two conflict**.

Paths in this file are written from the repository root, which is `~/ai` on `lin001`.

---

Assumes: a checkout at `~/ai` on `lin001`, and the Caddy + Authelia + `proxy`
stack already running (it is — this host has served demos for months).

## 1. Secrets

Three `0600` env files under `~/ai/`, never in Git. Every key is listed with no
values in [`.env.example`](../.env.example).

```bash
mkdir -p ~/ai && cd ~/ai
install -m 600 /dev/null pg-ai.env
install -m 600 /dev/null api.env
install -m 600 /dev/null langfuse.env
```

Follow the `~/authelia/authelia.env` precedent. The Grafana admin password
sitting in plain text in `~/docker-compose.yml` is a known defect on this host,
not a pattern to copy.

## 2. Phase 1 — `pg-ai`

```bash
./scripts/deploy.sh phase1
```

Creates `/datadisk/pg-ai`, starts `pg-ai`, applies the schema and roles, loads
`equipment.csv` and `tags.csv` with their alias arrays, and — while
`USE_FIXTURES=true` — loads the fixture stand-in for `imh`.

Three roles come out of this, and the split matters: `agent_ro` for the answer
path (SELECT only, everywhere), `cube_rw` for pre-aggregations, and `ingest_rw`
— the only role that writes `doc_chunks`. Set all three passwords in the `0600`
env files; `INGEST_DB_USER` / `INGEST_DB_PASSWORD` are what Phase 3 connects
with, and Phase 3 refuses to start without them.

**Gate:** `pg-ai` healthy, `vector` present, `agent_ro` can SELECT and cannot
INSERT, `ingest_rw` can write `doc_chunks` and nothing else, every equipment item and tag has an alias, `pg-ai` publishes no host
port and is not on the `proxy` network, and `df -h /` is unchanged.
`./scripts/verify.sh` checks all of it.

## 3. Phase 2 — Langfuse

```bash
./scripts/deploy.sh phase2
```

Deployed early on purpose: from here on, every experiment is traced. Then do
the manual steps the script prints — DNS, Caddyfile, Authelia rule, announce
the Authelia restart.

## 4. Phase 3 — knowledge base

Put the controlled documents on the host, in the folders that determine
`doc_type`:

```
/datadisk/ai-docs/{procedures,manuals,rationalisation,design}/
```

```bash
docker compose -f ~/ai-compose.yml run --rm ai-ingest --all
```

It will ask you to confirm the document number, revision and effective date for
every file. **Confirm them properly.** A wrong revision on a procedure is a
safety issue, not a data-quality one. When a new revision lands:

```bash
docker compose -f ~/ai-compose.yml run --rm ai-ingest --supersede WRPS-OPS-014 4
```

That sticks. Re-ingesting a superseded document brings it back superseded, and
`--all` skips it — the flag is not reset by replacing chunks. To undo one:

```bash
docker compose -f ~/ai-compose.yml run --rm ai-ingest --restore WRPS-OPS-014 3
```

This is the SSH path, and it stays. Phase 9 adds the same thing as a screen, so
that an operator who is issued a new document when the PLC logic changes does
not have to find someone with a host login. It does not remove the header
confirmation or the supersede decision — it puts them in front of a named
person and records the answer. See step 8 below.

## 5. Phase 4 — `imh` ⚠ PENDING

**The only true blocker.** Start the conversation now; do not wait for Phase 3.
Agree the read-only login, the table names and key columns, the timestamp
semantics, and an NSG rule allowing `lin001` → `imh` on 1433 only. Then update
§10 of `BUILD-AI-CONTAINERS.md` with the real schema and change
[`db/002_fixtures.sql`](../db/002_fixtures.sql) and the Cube models to match.

Until then everything runs on fixtures, and every answer carries a fixture
banner all the way to the operator's screen.

**The three Phase 5 findings are fixed** (2026-08-31), against the SCADA
configuration rather than against the fixtures. All three came from one
substitution: the stand-in historian was keyed on names delivered as
`PS_STN_WET_WELL_LEVEL` when the historian is keyed on CI Server **item** names
(`AID.WRPS.STN.LEVEL`). Those `PS_*` names turned out not to be CI Server names
at all — a corrected delivery on 2026-09-01 replaced them, and the seed is now
keyed on the item throughout. Nothing is aliased across that gap:
`public.historian_items` holds the mapping, generated from
[`db/seed/scada-source/`](../db/seed/scada-source/README.md) by
[`scripts/gen_historian_items.py`](../scripts/gen_historian_items.py),
and an item that resolves to neither a tag nor a written reason is a build
error rather than a silent "no records found".

Two consequences worth knowing before you read a number off this system:

- **The historian keeps seven days.** Every WRPS history group is
  `LIFE_TIME "1 weeks"`, and the fixtures now match, so a question about last
  month fails here exactly as it would against `imh`. Zero rows outside
  retention is reported as a retention limit, never as "nothing happened".
- **Equipment is asserted in exactly one place**, `tags.equipment_id`. The
  history carries no equipment column, because CI Server's section tree stops
  at the station and the three pumps and has no wet well to put there.

Full detail in [`BUILD-AI-CONTAINERS.md`](BUILD-AI-CONTAINERS.md) Phase 4,
"Resolved 2026-08-31". Eval cases `H26`, `H27` and `H31` cover them, and `H29`
covers the retention limit.

## 6. Phases 5–7 — Cube, API, UI

```bash
./scripts/deploy.sh api      # cube + ai-api
./scripts/deploy.sh web      # ai-web
./scripts/verify.sh
```

Each prints the manual DNS/Caddy/Authelia steps.

**DNS is done as of 27 August 2026**: `ai`, `api` and `cube` all resolve to
`20.211.144.151`, and the DC carries the pinpoint record `ai.yokogawa.tech` →
`10.0.0.17` that the Azure hairpin requires. The Caddyfile blocks and Authelia
rules for the three names still have to be applied on the host — until they
are, the names resolve and nothing answers.

**The operator console is unauthenticated, and only from the SCADA machine.**
Applied 28 August 2026 at the customer's direction. The `ai.yokogawa.tech` Caddy
block admits `remote_ip 10.0.0.21` (`yau-poc-cicore1`, static) and returns 403
to everything else — LAN, VPN and internet alike. An operator at the console
should not complete a Duo push to ask a question; nobody outside the plant
should reach the assistant at all.

Read this before relying on it. It is an **IP allowlist on a flat network with
no OT/IT boundary**: anything that can take `10.0.0.21` inherits unauthenticated
access. It is a demo affordance, not a security control, and it is listed as
such in [`BUILD-AI-CONTAINERS.md`](BUILD-AI-CONTAINERS.md) §14. It also makes
Langfuse traces anonymous — there is no longer a record of who asked what — and
it puts the assistant out of browser reach over the VPN, so engineers need an
SSH tunnel. `api.yokogawa.tech` is unchanged and still fully gated; Phase 9
document publishing depends on that and must stay there. Rollback is a Caddy
reload — the Authelia rule was left in place on purpose. See
[`caddy/ai-routes.caddy`](../caddy/ai-routes.caddy).

**This is in scope for the §2 OT/safety review**, which is still outstanding.

**`api.yokogawa.tech` has no pinpoint record and does not resolve inside the
VNet.** That is why the Phase 7 Caddy block routes `/ask` under
`ai.yokogawa.tech` to `ai-api` and the page is same-origin: a cross-origin
build loads on a control-room PC and then fails every question on DNS. Only
`/ask` is routed there — see the warning in
[`caddy/ai-routes.caddy`](../caddy/ai-routes.caddy) before widening it.

## 7. Phase 8 — validate

```bash
python eval/run_eval.py --api https://api.yokogawa.tech
```

Every case in [`eval/testset.jsonl`](../eval/testset.jsonl) is engineer-reviewable, and every
data-dependent one with a **pinned time window** — `imh` is live, and an
unpinned question gives a different answer each run.

Gate: ≥85% overall, ≥95% classification accuracy on Procedural and Advisory,
**zero** contract violations, p95 under 12 s. `run_eval.py` returns non-zero if
any of those is missed. It also marks Historical and Advisory cases
`needs_review`: whether "6" is the *right* number is a judgement for an
engineer with access to `imh`, not something this script can decide.

## 8. Phase 9 — operator document upload

**BUILT AND LIVE 2026-08-28, ahead of Phase 8, at the customer's direction.**
The screens are at `https://api.yokogawa.tech/documents` — served by `ai-api`,
not `ai-web`, because `ai.yokogawa.tech` is now SCADA-only and carries no
identity at all. Upload → convert → review → approve, plus withdraw and
restore. The pool screen was explicitly descoped.

Files are converted to text with pypdf / python-docx / openpyxl and the
converted text is shown to the reviewer before approval — the raw file is never
what the assistant reads, and a bad conversion is meant to be caught by eye.
**Scanned documents cannot be read** and are refused rather than stored empty.

Two things to know before trusting it. **Identity is self-asserted**: the
publisher is a typed name checked against a one-entry list (`admin`) with no
password, so anyone who reaches the page can claim it. Rows are marked
`demo:<name>` / `DEMO-UNVERIFIED` so they stay distinguishable from
authenticated ones later. And **the two ingest paths must not be used on the
same document** — files published through the UI stay in the inbox and
`ai-ingest --all` cannot see them. Full list of divergences in
[`BUILD-AI-CONTAINERS.md`](BUILD-AI-CONTAINERS.md) §14.

The design below is what §16 specifies, and remains the target.

**After Phase 8 passes, not before.** When the PLC logic or the SCADA program
changes, a new document is issued and the assistant is wrong about the plant
until it is ingested. Today that needs SSH to a live shared host. Phase 9 puts
it behind the UI:

```
upload  ─►  pre-scan  ─►  review  ─►  approve  ─►  published
(anyone    (worker,      (a named    (header      (chunks
 with 2FA)  Docling)      publisher)  confirmed)   citable)
```

Nothing is citable until a named person in `AI_DocPublishers` has confirmed the
document number, revision and effective date, and decided what it supersedes —
the same questions `ingest.py` asks at a terminal, asked on a screen and, unlike
the terminal, recorded. The database refuses an approved row without them.

```bash
psql -h pg-ai -U postgres -d plant -f db/004_doc_uploads.sql
psql -h pg-ai -U postgres -d plant -f db/005_doc_actions.sql
psql -h pg-ai -U postgres -d plant -f db/006_doc_pool.sql
sudo install -d -o 10002 -g 10002 /datadisk/ai-docs-inbox   # check df -h first
sudo install -d -o 10002 -g 10002 /datadisk/ai-docs-withdrawn
docker compose -f ~/ai-compose.yml up -d ai-docs-worker
```

**Taking documents out is the other half**, and today there is no way to do it:
`--supersede` needs a revision to *keep*, so a cancelled procedure or a manual
for equipment that has been removed cannot be withdrawn at all. Phase 9 adds
**withdraw** (immediate, reversible, keeps the chunks and the audit trail — this
is what "remove it" almost always means), **restore**, and **purge** (deletes,
irreversible, off unless `ALLOW_PURGE=true` and the publisher types the document
number). All three need the publisher group and a written reason, and all three
are recorded in `doc_actions`, which nothing can delete from.

Withdrawal also moves the file out of `/datadisk/ai-docs` into an archive, so
that folder keeps meaning "the documents this plant runs on". That is
housekeeping, not the safety mechanism: `ingest.py` reads a document's
withdrawal state before replacing its chunks and carries it through, and `--all`
skips withdrawn documents — so re-ingesting cannot resurrect one, whatever
folder it is in. `--restore DOC_NUMBER REVISION` is the way back, and it refuses
while another revision of the same document is live.

Then the manual steps: the `copy_headers` change on the `api.yokogawa.tech`
Caddy block, the `^/docs/.*` Authelia rule **above** the general one, and
`AI_DocPublishers` in AD with **direct** membership.

Design and gate: [`BUILD-AI-CONTAINERS.md`](BUILD-AI-CONTAINERS.md) §16 and
Phase 9. Two gate items matter most. A user who is authenticated but not a
publisher must get a **403 from the API**, tested by calling `api.yokogawa.tech`
directly — the button being hidden proves nothing. And after withdrawing a
document, `ai-ingest --all` must **not** bring it back; run it and check, because
that is the failure that puts a withdrawn procedure back in front of an
operator.

**Choosing what is in the pool** is a third, separate thing, and it is separate
on purpose. `superseded` says *this document is withdrawn or replaced* — a claim
about the document, with a reason and an audit row behind it. `pool_enabled`
says *this document is part of the set we are running with* — a claim about the
corpus, and no comment on whether the document is current. Retrieval requires
both, so putting a withdrawn document back in the pool does **not** make it
citable. A superuser curates the pool to keep it current; the same screen saves
named profiles.

**For demos**, `POST /ask` takes an optional `pool_profile` that narrows
retrieval **for that one request** and changes nothing stored — so "three
documents versus forty-seven" needs nothing undone afterwards on a host other
people are using. Every answer from a reduced pool carries a banner with the
document count, in the same place and for the same reason as the fixture-data
banner: an answer from a trimmed corpus is otherwise indistinguishable from a
complete one. The demo worth showing is not "more documents, better answers" —
it is that with the evidence removed the assistant says *no governing procedure
in the active document set*, rather than degrading into something plausible.

Read the HNSW note at the top of [`db/006_doc_pool.sql`](../db/006_doc_pool.sql)
**before** rehearsing that demo. The index covers every embedding and filters
afterwards, so a heavily trimmed pool can appear to collapse retrieval entirely.

**What none of it does:** update `tags.csv`, the Cube models or any
setpoint. A new design document changes what the assistant can *cite*; the
numbers behind Historical and Advisory answers still come from reference data
that is changed in Git and deployed. The review screen asks the reviewer to
confirm they know that, because a document going live while the tag metadata
behind it has not is a gap that is only visible at that moment.