Server Ops Guide¶
For anyone running a dedicated fl-server.
A server needs no configuration file to start — it writes a commented default server.toml on
first run and listens on port 4778. Everything below is about changing that default sensibly.
| Page | What it covers |
|---|---|
| Server configuration | Every server.toml key with its type, default and range; every CLI flag; the full admin command reference; and which keys hot-reload |
| Admin API | The REST endpoints, bearer-token auth, the unauthenticated health probe, and what each route returns |
| Agent surface (MCP) | Exposing the server to AI agents over MCP, the autonomy tiers, and the security model that bounds them |
| Metrics | The --metrics-json report: every field, what a bad value looks like, and what to do about it |
| Lobby API | Registering with a lobby so players can find the server |
Before you expose a server¶
Three settings decide whether a public server is safe, and all three are off or closed by default. If you turn any of them on, read the page that owns it first:
[http_admin]— the REST admin API can kick, ban and shut the server down. It refuses to start with no tokens, binds to localhost by default, and should stay behind a reverse proxy.[ai.mcp]— the agent surface rides the same listener and the same token table. Its default autonomy tier is read-only; raising it grants an agent the ability to act.[rcon]— the TCP admin channel. Off by default, and it warns at startup if enabled with an empty password.
Per-IP lockout guards all three the same way; see Server configuration for the thresholds.