Every BB.TUI session rides on ExRatatui's :telemetry instrumentation. The runtime wraps mount, every input event, every PubSub/info dispatch, and every frame in spans with :start / :stop / :exception events; transport connect/disconnect and session open/close fire as single events. All metadata carries :mod (BB.TUI.App for any TUI session) and :transport (:local, :ssh, :distributed, or :cell_session).
Development logger
A one-call default Logger handler is exposed for development:
BB.TUI.attach_telemetry_logger()
# or, scoped to a single level / event subset
BB.TUI.attach_telemetry_logger(level: :info)
BB.TUI.detach_telemetry_logger()Production observability
For production, attach a custom handler that ships into Telemetry.Metrics, OpenTelemetry, or whatever the consumer app already uses. See ExRatatui.Telemetry for the full event reference — event names, measurement units, and metadata shapes.