Summarises the running container's keepalive: extension count, latest budget, transient failures, rejections, restarts. It deliberately makes no API call. Any authenticated request slides the session TTL, so a checker that talked to Schulcloud would be sustaining the session itself and could not report on whether the keepalive is doing it — the same confound that made the first endurance test ambiguous. Reading container logs observes without participating. Warns when the reported budget drops below 7000s, which is the early signal that extensions have stopped taking effect. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Deployment
The shape of it
claude.ai ──HTTPS──▶ VPS (public IP) ──tunnel──▶ Pi 5 (home network)
└─ Caddy ──▶ schulcloud-mcp:8080
│
└──▶ schulcloud-thueringen.de
Claude's custom connectors call the endpoint from Anthropic's cloud, 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.
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
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
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:
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:
networks:
caddy:
external: true
name: <the network name you just found>
Append deploy/Caddyfile.snippet to the Pi's Caddyfile, replacing
mcp.example.org with the real hostname, and reload:
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_timeoutof 300s — asearchcall walks every course and can take tens of seconds. Caddy's defaults will cut it off.
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
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
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 → Settings → Connectors → Add custom connector.
- URL:
https://mcp.example.org/mcp - Under Advanced settings, add the bearer token as an authorization
header. If your organisation has no header-auth field, the server also
accepts the token as
X-Api-Key. - Enable the connector in a conversation via + → Add connectors.
Ask "which courses am I in?" as a first check — that exercises auth, the Schulcloud token and the API in one call.
Running it locally instead
For Claude Code or Claude Desktop on your own machine, skip all of the above and use stdio:
{
"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
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: ALLandno-new-privileges, running as the unprivilegednodeuser. It writes nothing to disk — downloads are streamed through memory, capped atMAX_DOWNLOAD_BYTES(25 MiB default). - The Schulcloud session has a 2-hour sliding TTL, so the server calls
refresh-sessionevery 30 minutes. Watch forkeepalive: session extended, 7200sin the logs, or runnpm run keepalive-statusfor 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 pasting a fresh
TSC_JWT_COOKIE. - Monthly chore: refresh
TSC_JWT_COOKIEbefore its 30-day hard expiry.npm run probereports both clocks.