PraisonAI's Slack bot applies its configured "allowed_users", "allowed_channels", and unknown-user pairing policy in the normal Slack "message" event handler, but not in the adjacent Slack "app_mention" event handler. A Slack workspace user who can mention the bot in a channel where the Slack app is present can trigger the configured PraisonAI agent even when: - the sender is not in "BotConfig.allowed_users"; - the channel is not in "BotConfig.allowed_channels"; - "unknown_user_policy="deny"" is configured; and - the same event content is correctly dropped by the normal "message" handler. This is a sibling-handler guard-coverage issue. Slack documents "app_mention" as a distinct event type rather than a "message.*" event, so deployments subscribed to app mentions can route unauthorized sender input around the guarded message path.