Environment Variables

The environment acts as an override layer on top of mc.toml, and is the only place mc reads secrets from — secrets are deliberately kept out of the manifest so it can be committed and shared safely.

MC_RCON_PASSWORD

The password for RCON, the remote console protocol used to coordinate backups with a running instance. It takes precedence over a "rcon.password" entry under [server.properties].

RCON is enabled exactly when a password is configured. When backups are enabled and no password is set anywhere, mc generates one at each start so backups work out of the box; set this variable when other tooling needs to reach the remote console with a known password.

MC_BACKUPS_S3_BUCKET

The S3 bucket that receives backup archives when [backups.storage] has type = "s3". It takes precedence over the bucket key in the manifest and can replace it entirely.

S3 credentials are not read through mc-specific variables; they come from the standard AWS credential chain — AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY, the ~/.aws configuration files, or an attached IAM role.

MC_DISCORD_WEBHOOK

The Discord webhook URL that notifications are posted to. Setting it is what turns notifications on; without it none are sent. The [notifications] section of the manifest selects which events are reported — instance lifecycle, crashes, forced shutdowns, and backup results are all on by default.