[Unit]
Description=MemPalace remote MCP server (the fleet primary — RFC-001)
Documentation=https://gitea.jordbo.se/joakimp/mempalace-toolkit
Documentation=file:%h/mempalace-toolkit/docs/rfc-001-global-palace.md
After=network-online.target
Wants=network-online.target
# Refuse to start if the palace is missing — better a clear failure than a
# server quietly creating an empty palace somewhere unexpected.
ConditionPathExists=%h/.mempalace/palace

[Service]
Type=simple
# ── Bind address: NOT 127.0.0.1. This is deliberate and load-bearing. ────────
# mempalace pins the HTTP Host header to loopback literals *only on a loopback
# bind* (mcp_server.py: enforce_host_pin = _http_is_loopback(host)). Behind a
# reverse proxy / tunnel that forwards the public hostname, a loopback bind
# answers 403 Forbidden. Verified empirically on synlig 2026-08-10:
#   bind 127.0.0.1  + Host: palace.example.com -> 403
#   bind 172.17.0.1 + Host: palace.example.com -> 200
# 172.17.0.1 is the docker0 gateway: non-loopback (so the pin relaxes), but
# reachable only from this host and its containers — so a newt/Pangolin tunnel
# container on this box can reach it while the LAN cannot. Use 0.0.0.0 only if
# the tunnel does not run in Docker here, and only with the firewall closed.
#
# The Origin check is NEVER relaxed: a request carrying a non-loopback Origin
# is 403 with no override. Fine for MCP clients (they send none); fatal for
# browser-based clients.
#
# No --token here on purpose: for a non-loopback bind, serve reuses or mints a
# 0600 token at ~/.mempalace/server/<hash-of-palace-path>/token and keeps it
# stable across restarts. Read it from there to configure clients; never paste
# it into this unit (units are world-readable).
ExecStart=%h/.local/bin/mempalace serve --host 172.17.0.1 --port 8765
Restart=on-failure
RestartSec=5s
# The server serializes every request behind one lock, so a wedged process is
# a fleet-wide outage. Fail fast and let Restart= recover.
TimeoutStopSec=30
# Journal: journalctl --user -u mempalace-serve -f
StandardOutput=journal
StandardError=journal
# Modest hardening (user units can't do much, but these are free)
NoNewPrivileges=true
PrivateTmp=true
ProtectKernelTunables=true
ProtectControlGroups=true

[Install]
WantedBy=default.target

# ── Enabling (needs one sudo, hence not done by the Phase 0 prep) ───────────
#   sudo loginctl enable-linger $USER     # else the unit dies with your login
#   systemctl --user daemon-reload
#   systemctl --user enable --now mempalace-serve
#   curl -s localhost:8765/healthz        # -> 403 (expected! see bind note)
#   curl -s 172.17.0.1:8765/healthz       # -> ok