Schulcloud-MCP/docs/DEPLOYMENT.md

# Deployment

## The shape of it

```
claude.ai  ──HTTPS──┐
                    ├─▶ VPS (public IP) ──tunnel──▶ Pi 5 (home network)
schulcloud CLI ─────┘                                └─ Caddy ─▶ schulcloud-mcp:8080
                                                                  ├─ /mcp      (Claude)
                                                                  ├─ /api      (CLI)
                                                                  ├─ Postgres  (index)
                                                                  ├─ mirror    (file bytes)
                                                                  └──▶ schulcloud-thueringen.de
```

Both front ends use the same hostname. `/mcp` speaks MCP; `/api` serves the
CLI's manifest, file bytes, re-crawl requests and token replacement; `/token` is
a page for pasting a fresh Schulcloud token.

Claude's custom connectors call the endpoint from Anthropic's cloud
(`160.79.104.0/21`), so it must be publicly reachable over real TLS — a
localhost tunnel or self-signed cert will not do. The VPS provides the public
address; Caddy on the Pi terminates TLS and obtains the certificate. **Keep the
VPS forwarding raw TCP** rather than terminating TLS itself: then it never sees
a request path, which matters once a path carries a secret (below).

**The Pi must stay up.** More than two hours offline ends the Schulcloud session
however long the token has left — a laptop that sleeps overnight loses it every
night. A replacement token fixes that without a restart (see *Replacing the
Schulcloud token*), but an always-on host is what avoids needing one.

The container publishes no host port. Caddy reaches it over the shared Docker
network, so the only way in from the internet is through Caddy and then through
this server's bearer check.

## First deploy

```bash
git clone <this repo> /opt/schulcloud-mcp
cd /opt/schulcloud-mcp

cp .env.example .env
# Fill in TSC_URL and TSC_JWT_COOKIE (see docs/AUTH.md), then:
openssl rand -hex 32   # → MCP_AUTH_TOKEN
openssl rand -hex 32   # → MCP_PATH_SECRET, only for claude.ai (see "Connecting Claude")

docker compose up -d --build
docker compose logs -f schulcloud-mcp
```

Expect:

```
[schulcloud-mcp] listening on 0.0.0.0:8080 — instance https://… , auth enabled, keepalive every 30min
```

`auth DISABLED` there means `MCP_AUTH_TOKEN` is empty — fix it before exposing
the service. A `keepalive: token rejected (401)` line right after startup means
the Schulcloud token is dead and needs replacing (see docs/AUTH.md); the server
will run but every tool will fail.

## Joining the existing Caddy

The Pi already runs Caddy and PostgreSQL in a Compose project. This server needs
neither a database nor its own Caddy — only a network it shares with the
existing one.

Find the network Caddy is on:

```bash
docker inspect -f '{{range $k,$v := .NetworkSettings.Networks}}{{$k}}{{"\n"}}{{end}}' <caddy-container>
```

Then in `docker-compose.yml`, set that name and mark it external:

```yaml
networks:
  caddy:
    external: true
    name: <the network name you just found>
```

### Postgres

The index needs a database. On the Pi, use the existing PostgreSQL rather than
the container in `docker-compose.yml` — create a database and user for it:

```sql
CREATE USER schulcloud WITH PASSWORD '…';
CREATE DATABASE schulcloud OWNER schulcloud;
```

Then set `DATABASE_URL` in `.env` and delete the `postgres` service from the
compose file. Migrations run automatically at startup; `pg_trgm` is created by
the first migration, which needs the database owner to be able to
`CREATE EXTENSION`.

Without `DATABASE_URL` the server still runs: search crawls live on every call
and `/api` returns `503`. The startup log says which mode it is in.

### Caddy

Append `deploy/Caddyfile.snippet` to the Pi's Caddyfile, replacing
`mcp.example.org` with the real hostname, and reload:

```bash
docker exec <caddy-container> caddy reload --config /etc/caddy/Caddyfile
```

Two settings in that snippet matter and are easy to miss:

- **`flush_interval -1`** — MCP's Streamable HTTP transport holds a
  server-sent-events channel open. Without this, Caddy buffers it and the
  connector hangs with no error.
- **`read_timeout`/`write_timeout` of 300s** — a `search` call walks every
  course and can take tens of seconds. Caddy's defaults will cut it off.
- **The `format filter` in `log`** — rewrites `/<secret>/mcp` before an access
  log entry is written. Without it every claude.ai request writes the secret to
  disk. Verified against Caddy 2.11: the entry reads `"uri":"/<secret>/mcp"`.

## Ports and DNS

- DNS for the hostname points at the **VPS**, not the Pi.
- The VPS forwards 80 and 443 to the Pi's Caddy. Port 80 must work too, or
  Caddy cannot complete the ACME HTTP challenge.
- Nothing else needs to be exposed.

## Verifying from outside

```bash
curl -s https://mcp.example.org/healthz
# {"status":"ok","sessions":0}

curl -s -o /dev/null -w '%{http_code}\n' -X POST https://mcp.example.org/mcp \
  -H 'content-type: application/json' -d '{}'
# 401   ← the bearer check is live

curl -s -o /dev/null -w '%{http_code}\n' -X POST https://mcp.example.org/$(openssl rand -hex 32)/mcp \
  -H 'content-type: application/json' -d '{}'
# 404   ← a wrong path secret looks like any unknown path
```

If `/healthz` answers but `/mcp` returns 401 with a correct token, check that
the token in `.env` matches the one in the connector exactly — no trailing
newline from a copy-paste.

## Connecting Claude

### claude.ai — a secret path, for now

claude.ai's *Add custom connector* dialog takes a name and a URL. Sending a
bearer token needs its "Request headers" section, a beta most accounts do not
have, and the proper answer — OAuth — is not built yet. Until it is, the
server can serve MCP at a path that is itself the secret:

1. Put `MCP_PATH_SECRET=<openssl rand -hex 32>` in `.env` and recreate the
   container: `docker compose up -d --force-recreate schulcloud-mcp`. The
   startup line then says `(plus secret MCP path)` — never the secret itself.
2. claude.ai → **Customize → Connectors → Add custom connector**. Name it, and
   give the URL `https://mcp.example.org/<secret>/mcp`. No sign-in.
3. Enable it in a conversation via **+ → Connectors**.

Ask *"which courses am I in?"* as a first check — that exercises the path, the
Schulcloud token and the API in one call.

**Know what this trades away.** The URL is now the credential, and Anthropic's
connector documentation calls credentials in URLs a security vulnerability,
because URLs end up in logs. This deployment keeps it out of its own: the
server never logs request paths, the Caddy snippet rewrites the segment to
`<secret>` in the access log, and a VPS forwarding raw TCP never sees it.
Caddy's *error* log can still name the path if the container is down while
claude.ai calls, and claude.ai stores the URL in its connector settings. There
is no revocation short of a new secret: change `MCP_PATH_SECRET`, recreate the
container, and add the connector again. Anyone holding the URL can read — never
change — the account. A wrong secret answers 404, like any unknown path.

### Claude Code and the CLI — the bearer token

Both can send a header, so they keep using `MCP_AUTH_TOKEN` on the plain `/mcp`
and `/api`:

```bash
claude mcp add --transport http --scope user schulcloud https://mcp.example.org/mcp \
  --header "Authorization: Bearer <MCP_AUTH_TOKEN>"
schulcloud login --server https://mcp.example.org --token <MCP_AUTH_TOKEN>
```

## Replacing the Schulcloud token

The token lasts 30 days at most and can only come from a browser login (see
docs/AUTH.md), so this is the monthly chore — but it no longer needs a restart
or an `.env` edit:

1. Log in to Schulcloud in a **private window** and copy the `jwt` cookie's
   value (DevTools → Application → Cookies).
2. Either run `schulcloud token set` and paste it, or open
   `https://mcp.example.org/token` and paste it together with `MCP_AUTH_TOKEN`.
3. **Close the private window.**

The server checks the token with Schulcloud first — right account, not
expired, not logged out — then swaps it in, restarts the keepalive and saves it
to the `state` volume (`STATE_DIR=/data/state`), so a restart keeps it. At
startup the newer of the saved token and `TSC_JWT_COOKIE` wins, unless the two
are for different accounts: changing `TSC_JWT_COOKIE` is how you switch
accounts. `schulcloud token` shows the days left; from a week before expiry the
log, `whoami` and the CLI warn about it.

## Running it locally instead

For Claude Code or Claude Desktop on your own machine, skip all of the above and
use stdio:

```json
{
  "mcpServers": {
    "schulcloud": {
      "command": "node",
      "args": ["/path/to/schulcloud-mcp/dist/bin/stdio.js"],
      "env": {
        "TSC_URL": "https://schulcloud-thueringen.de",
        "TSC_JWT_COOKIE": "…"
      }
    }
  }
}
```

`MCP_AUTH_TOKEN` is irrelevant in stdio mode — there is no network listener.

## Updating

```bash
cd /opt/schulcloud-mcp && git pull
docker compose up -d --build
docker compose exec schulcloud-mcp node -e "1" # sanity
npm run probe                                  # re-verify the API assumptions
```

## Operational notes

- **Restart policy** is `unless-stopped`; the container comes back after a
  reboot.
- **Sessions** are in-memory and dropped after 30 minutes idle. A restart
  invalidates them; Claude re-initializes transparently.
- **Logs** are capped at 3 × 10 MB. The Authorization header is never logged.
- **The container is read-only** with `cap_drop: ALL` and `no-new-privileges`,
  running as the unprivileged `node` user. The writable paths are the mirror
  volume at `/data/mirror`, which holds downloaded file bytes, and the state
  volume at `/data/state`, which holds a replaced Schulcloud token (mode 0600).
  Both belong in no backup that leaves the Pi unencrypted.
- **The mirror grows.** It holds a copy of every course file under
  `MIRROR_MAX_BYTES` (64 MiB default). Larger files — videos, mostly — are
  indexed as metadata and proxied live on request instead. Budget a few GB.
- **A re-crawl of unchanged content downloads nothing**, because Schulcloud file
  records are immutable, so the 6-hourly crawl costs a few hundred cheap GETs in
  the steady state.
- **The Schulcloud session has a 2-hour sliding TTL**, so the server calls
  `refresh-session` every 30 minutes. Watch for
  `keepalive: session extended, 7200s` in the logs, or run
  `npm run keepalive-status` for a summary.
- **Never leave a Schulportal tab open on the token you deployed.** It shares
  the session and its auto-logout will revoke it ~2h after login. Copy the
  cookie in a private window and close it — see docs/AUTH.md.
- **Downtime longer than two hours lapses the session** and restarting does not
  recover it: a long power cut means handing the server a fresh token
  (`schulcloud token set`), no restart needed.
- **Monthly chore**: replace the token before its 30-day hard expiry — see
  *Replacing the Schulcloud token*. `schulcloud token` and `npm run probe`
  report the clocks.