diff --git a/projects/ProvinceSystem/DEPLOY.md b/projects/ProvinceSystem/DEPLOY.md
index 3eef19d..8eb12ef 100644
--- a/projects/ProvinceSystem/DEPLOY.md
+++ b/projects/ProvinceSystem/DEPLOY.md
@@ -71,7 +71,7 @@ the owner of both checkouts. Deploys to the same site run one at a time.
 
 1. Refuses commits not on `origin/main` (exit 4) and, on www, a checkout with uncommitted changes to tracked files
    (exit 1). On dev, `git checkout --detach` keeps the expected local edits and refuses if they would be overwritten.
-2. Backs up `province.db` with SQLite's backup API inside the backend container as `province.db.before-deploy-<sha>-<UTC time>`, keeping the newest 10.
+2. Backs up `province.db` with SQLite's backup API inside the backend container as `province.db.before-deploy-<sha>-<UTC time>`, keeping the newest 10. When the compose file has a `db` service, it starts it and writes `postgres.before-deploy-<sha>-<UTC time>.dump` (`pg_dump --format=custom`), also keeping 10.
 3. Rebuilds only what changed: `frontend/`, `shared/` or `docker-compose*` rebuild the frontend; `backend/`,
    `shared/`, `frontend/lib/skins/` or `docker-compose*` rebuild the backend (`up -d --build --no-deps`).
    Other changes only move the checkout.
@@ -118,6 +118,23 @@ files out of images, so a local `docker-compose.staging.yml` run gets only the s
 sync to the site go to `backend/src/data/plugin-assets/`, inside the data mount. Both compose files run the backend and
 frontend with `init: true`; in the backend it reaps the renderer's Chromium processes.
 
+### The site's Postgres
+
+Each compose project has a `db` service (`pgvector/pgvector:pg17`) holding Precedent and patch notes, in the
+volume `provincesystem_db` (www) or `tfmc-staging_db` (Dev). It has no host port; the backend reaches it as `db`
+and waits until it is healthy. Each site's password is `POSTGRES_PASSWORD` in its project's `.env`
+(`/home/tfmc/ProvinceSystem/.env` or `/home/tfmc/tfmc-staging/.env`, mode 600; hex, as it goes into a URL), and www's
+`backend/.env` sets
+`DATABASE_URL=postgresql://provincesystem:<password>@db:5432/provincesystem`. Dev's compose file builds `DATABASE_URL`
+from the same password, and its override repeats it because its `environment: !override` replaces the list.
+Postgres reads `POSTGRES_PASSWORD` only when it creates the volume; to change the password later, run
+`ALTER USER provincesystem PASSWORD '…'` in `psql` and update both files.
+
+```bash
+sudo -u tfmc ps-compose main exec db psql -U provincesystem provincesystem      # a shell
+sudo -u tfmc ps-compose main exec -T db pg_restore -U provincesystem -d provincesystem --clean --if-exists < backup.dump
+```
+
 ## Keys and secrets
 
 | Secret | Where | Used by |
diff --git a/projects/ProvinceSystem/docs/integrations/precedent.md b/projects/ProvinceSystem/docs/integrations/precedent.md
index 54179f5..a7b467d 100644
--- a/projects/ProvinceSystem/docs/integrations/precedent.md
+++ b/projects/ProvinceSystem/docs/integrations/precedent.md
@@ -9,7 +9,7 @@ similar incidents get similar rulings. Bot never decides punishments — it's ad
 
 1. Staff run `/case-log` after handling an incident (players, rule broken, evidence
    summary, ruling, punishment) → cog POSTs to ProvinceSystem → ProvinceSystem embeds
-   the case (Voyage AI) and stores it in Supabase Postgres (`pgvector`).
+   the case (Voyage AI) and stores it in the site's Postgres (`pgvector`).
 
    **Only the summary is embedded** (`_case_text` in `precedent_routes.py`). A search
    query is always a description of what happened: staff cannot cite the rule number
@@ -117,9 +117,10 @@ Implementation: `backend/src/api/precedent_routes.py`, `backend/src/precedent/{d
 
 ## Audit trail
 
-Every write to `precedent_cases` appends a row to `precedent_audit` in the same Supabase
-database. There is **no API route to read it** — inspecting it requires direct Supabase
-access, so staff cannot review or erase their own trail from the website.
+Every write to `precedent_cases` appends a row to `precedent_audit` in the same database.
+There is **no API route to read it**: inspecting it takes database access (the root-only
+[Database studio](../ops/database-studio.md) or `psql` on the host), so staff cannot review or
+erase their own trail from the website.
 
 | Column | Meaning |
 |--------|---------|
@@ -161,8 +162,9 @@ corpus). Ids that already exist are skipped rather than overwritten, so the scri
 re-run and safe to use while the corpus is only partly damaged. Restores are themselves
 audited, as `action='restore'`, `source='script'`.
 
-**This only covers deletions made through the API.** Direct SQL against Supabase bypasses the
-audit trail entirely — Supabase's own backups are the recovery path for that.
+**This only covers deletions made through the API.** Direct SQL bypasses the audit trail; the
+`postgres.before-deploy-*.dump` files that each deploy writes ([DEPLOY.md](../../DEPLOY.md)) are
+the recovery path for that.
 
 Useful queries:
 
@@ -180,19 +182,19 @@ SELECT before FROM precedent_audit WHERE action = 'delete' AND case_id = '<uuid>
 
 ## Storage
 
-Supabase Postgres, `pgvector` extension. Two tables: `precedent_cases` (id, logged_by,
+The site's Postgres (the `db` service in each site's compose project), `pgvector`
+extension. Two tables: `precedent_cases` (id, logged_by,
 players, summary, rule, ruling, punishment, embedding `vector(1024)`, created_at) and
 `precedent_audit` (see above). Tables + extension are created lazily on first request
 (`migrate()` in `precedent/db.py`).
 
-This is separate infrastructure from the existing SQLite skins/drinks DB — ProvinceSystem
-had no Postgres/Supabase usage before this feature.
+Patch notes share the same database; the rest of the site is still in SQLite (`province.db`).
 
 ## Configuration
 
 | Env (ProvinceSystem `backend/.env`) | Purpose |
 |--------------------------------------|---------|
-| `SUPABASE_DB_URL` | Postgres connection string (Supabase project) |
+| `DATABASE_URL` | The site's Postgres, `postgresql://provincesystem:<password>@db:5432/provincesystem` |
 | `VOYAGE_API_KEY` | Voyage AI embeddings |
 | `ANTHROPIC_API_KEY` | Claude synthesis |
 
diff --git a/projects/ProvinceSystem/docs/ops/database-studio.md b/projects/ProvinceSystem/docs/ops/database-studio.md
index 4540d43..81a00fe 100644
--- a/projects/ProvinceSystem/docs/ops/database-studio.md
+++ b/projects/ProvinceSystem/docs/ops/database-studio.md
@@ -15,7 +15,7 @@ Each site lists the databases it can reach:
 |----|------|--------|
 | `site` | `province.db`: accounts, characters, wardrobes, chronicle and ledger indexes, the staff audit log | Read and edit |
 | `coreprotect` | The CoreProtect SQLite file named by `COREPROTECT_DB` (Main on www, Dev on the Dev site) | Read only |
-| `supabase` | The Postgres database in `SUPABASE_DB_URL` (Precedent and patch notes), `public` schema; www only | Read and edit |
+| `postgres` | The site's Postgres in `DATABASE_URL` (Precedent and patch notes), `public` schema | Read and edit |
 
 The list shows each database's tables, size and how many audited queries it has had.
 Opening one shows its tables with columns and approximate row counts (`max(rowid)` on