Schulcloud-MCP/docs/DEPLOYMENT.md

Deployment

This page explains the moving parts and why each is there. For the steps in order, on the Pi, follow PI.md.

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, whose header or path carries a credential (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

PI.md steps 1–5: log in to registry.mc02.dev, clone to /opt/schulcloud-mcp for the compose files, write .env (the Pi's COMPOSE_FILE, CADDY_NETWORK and POSTGRES_PASSWORD, generated secrets, the first Schulcloud token), then:

docker compose pull
docker compose up -d
docker compose logs -f schulcloud-mcp

Expect:

[schulcloud-mcp] listening on 0.0.0.0:8080 — instance https://… , auth enabled (plus secret MCP path), token from environment, 29 day(s) left, keepalive every 30min, index every 6h

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 in a container. This server needs no Caddy of its own — only to sit on the same Docker network, so Caddy reaches it by name and no host port is published.

That is what deploy/docker-compose.pi.yml does, and the Pi's .env selects it with COMPOSE_FILE=docker-compose.yml:deploy/docker-compose.pi.yml, so plain docker compose commands pick it up and nothing tracked needs editing. It declares the Caddy network external under the name in CADDY_NETWORK. Setting COMPOSE_FILE also matters for what it leaves out: without it, Compose merges docker-compose.override.yml, which is for local development and publishes ports.

Postgres

The index gets its own Postgres container, on a network shared with this server and nothing else — not with Caddy, and not with whatever else is on Caddy's network. The Pi file builds DATABASE_URL from POSTGRES_PASSWORD. Migrations run at startup; the first creates pg_trgm.

An existing Postgres works as well: create a database and a user that owns it (it must be able to CREATE EXTENSION), point DATABASE_URL at it, and remove the postgres service and the depends_on that names it. Nothing requires sharing one.

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:

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

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 request header with a token of its own

claude.ai's Add custom connector dialog asks for a name and a URL first. Its authentication settings, Request headers among them, appear on the next step, once it has probed the URL.

1. Put MCP_CONNECTOR_TOKEN=<openssl rand -hex 32> in .env and recreate the container: docker compose up -d --force-recreate schulcloud-mcp. The startup line then says (plus connector token).
2. claude.ai → Customize → Connectors → Add custom connector. Name it, and give the URL https://mcp.example.org/mcp.
3. On the next step keep No sign-in, which is what Claude detects, and add a request header: name authorization, value Bearer <MCP_CONNECTOR_TOKEN>, space included. A bare token, or the header x-api-key, works too.
4. Enable it in a conversation via + → Connectors.

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

Why a token of its own. claude.ai stores the header value, so the token is a credential held by a third party. MCP_CONNECTOR_TOKEN opens /mcp, the read-only tools, and is refused on /api, which can replace the Schulcloud token and stream the file mirror. It also rotates alone: set a new value, recreate the container, then remove the connector and add it again, because claude.ai cannot edit a stored header. Claude Code and the CLI are unaffected.

Without request headers — a secret path

For a client that cannot send a header, 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. The startup line then says (plus secret MCP path) — never the secret itself.
2. Give the client the URL https://mcp.example.org/<secret>/mcp, with no header and no sign-in.

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:

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:

{
  "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.

Publishing an image

The Pi never builds: deploy/docker-compose.pi.yml runs registry.mc02.dev/schulcloud-mcp and removes the build section it would otherwise inherit. Images are published from a development machine:

npm run publish-image
docker buildx imagetools inspect registry.mc02.dev/schulcloud-mcp:latest   # lists linux/amd64 and linux/arm64

scripts/publish-image.sh refuses a working tree with uncommitted changes, so a tag always names exactly the code of one commit. It builds for linux/amd64 and linux/arm64 and pushes two tags: latest, and the short commit id. It also labels the image with the full commit and the repository.

Two things the build machine needs:

• arm64 emulation on an x86 machine. The script checks for it and prints the command that registers QEMU — docker run --privileged --rm tonistiigi/binfmt --install arm64 — which lasts until the next reboot.
• A multi-platform push. Docker's containerd image store supports it directly. Without that store, create a builder first with docker buildx create --use.

Updating

npm run publish-image                          # on a development machine
cd /opt/schulcloud-mcp && git pull             # on the Pi: compose files and docs
docker compose pull && docker compose up -d
npm run probe                                  # on a development machine: re-verify the API assumptions

A .env that pins SCHULCLOUD_MCP_TAG needs the new commit id before the pull. Setting the previous one rolls back.

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.