Install the Companion control plane

Sovereign Sync is owned by prometheus-companion. The skill pack remains complete without it and does not build, install, start, stop, or repair the Companion service.

From a prometheus-companion checkout, use the Companion-owned installers:

bash scripts/install-companion-service.sh
bash scripts/install-skill-package.sh

The first command installs the Companion process and its control endpoint. The second publishes /sync-status, /sync-peers, and /sync-push through the Companion's skill package. Re-run the same commands after upgrading the Companion.

The pack discovers the optional endpoint through integration-contract seam 1. Absence is valid and does not produce a warning:

prometheus contract show --json
prometheus doctor --json --check control

Contract v1 retains the compatibility identifiers SOVEREIGN_SYNC_SOCKET, sovereign-sync.sock, and the existing device-key path. They identify the open transport contract; they do not make the daemon a skill-pack component.

For process and pairing details, continue with Pair two machines and P2P network from the Companion checkout.