Where do messages enter and leave?

Inbound traffic enters through a platform Endpoint; outbound traffic ends at an Endpoint. For a receive problem, trace Endpoint, inbound middleware, then command dispatch.

For a send problem, trace $reply, rendering, outbound middleware, then Endpoint delivery.

This path concerns ordinary IM messages. Requests, notices, and login state have their own event projections; do not debug them as one message.receive event.

When a message arrives

The platform Client hands it to an Endpoint, which calls emit('message.receive', payload). Runtime holds a snapshot of that event's generation, constructs a Message, runs inbound middleware, and dispatches commands.

A command miss can reach AI fallback only when Agent is installed.

If middleware never sees the message, check whether the Endpoint emitted message.receive, then its inbound capability and active generation.

If a command stays silent, check the prefix, command discovery, and whether middleware calls next().

When a reply leaves

A command return value or Message.$reply() enters the shared outbound path: render and normalize content, run outbound middleware, call AdapterIndex.send, then the target Endpoint's send().

Proactive sends also use OutboundMessageService.send so rendering and middleware still apply.

The Endpoint must declare outbound and be started. When code ran but nothing reached the platform, check those conditions and outbound middleware first.

See Message Flow for the complete pipeline and event shapes, and the adapter index for platform-specific delivery.