The agent runs in n8n on the box and reaches its model over the mesh from
episode five, so no prompt leaves the network. It gets three read-only tools
(recent commits, monitor status, wiki search) and returns one suggested
action as a field. A switch compares that field against three allowed values,
and only one of them reaches ops-actions, a small runner holding its own
hard-coded allowlists for actions and targets.
Measured while building this: the same prompt injection was harmless in every
place the agent reached through a tool (twenty runs, no hits) and worked every
time it arrived in the alert itself, through a poisoned monitor name (thirteen
of thirteen). The allowlist rejected all thirteen. It guards the action field
only, so the attacker-written summary still reached the wiki unchanged; the
triage note now truncates and strips every field it did not write itself.
Three workflows that connect the services from episodes 1 to 7: a Forgejo push
becomes a phone notification, an Uptime Kuma outage writes and closes its own
incident page in Outline, and a nightly schedule writes one ops digest.
The point of the episode is the split between webhooks and the editor. Caddy
publishes only the webhook path prefixes under the n8n host and answers an
empty 404 for everything else, so the editor stays reachable over the mesh from
episode 5 and never gets a login page on the open internet.
Also in here:
- n8n pinned to a version instead of :latest, after episode 7 showed that every
restore is otherwise an upgrade
- the 2.x environment that actually matters, including the file access
restriction pointed at one directory rather than the root
- the Forgejo allowed host list, without which a webhook to a private address
is silently dropped
- fixed subnets for both docker networks, after a restore handed them out in
the other order and quietly broke the mesh route
- a note on the encryption key: it decrypts every stored credential, it lives in
the n8n volume, and a backup without it restores a hub that cannot log in
Claude-Session: https://claude.ai/code/session_01Md8yhBKp5e7xMmCyxoEgdm
