mcpprogress

A mcpprogress.Notifier is a sink that sends the progress notifications of the Model Context Protocol: how many targets of the call ended, of how many, and a line for a person, such as read the groups: 3/16 done, 1 failed.

The package imports no MCP SDK. The server gives it a Send that puts the progress token in the notification and sends it on the session. So the kit follows no release of an SDK (decision 3).

var last string
n := mcpprogress.New(mcpprogress.Options{
	Send: func(_ context.Context, progress, total float64, message string) error {
		last = fmt.Sprintf("%v/%v %s", progress, total, message)
		return nil
	},
})
bus := progress.NewBus(progress.BusOptions{Sinks: []progress.Sink{n}, Program: "prog"})
ctx := progress.WithBus(context.Background(), bus)

fanout.Map(ctx, []string{"exe1", "exe2", "exe3"}, fanout.MapOptions[string]{Step: "probe the nodes"},
	func(context.Context, string) (struct{}, error) { return struct{}{}, nil })

bus.Close()
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
if err := n.Close(ctx); err != nil {
	fmt.Println(err)
}
fmt.Println(last)

3/3 probe the nodes: 3/3 done

What it sends#

• The total is the Total of each step or batch that counts its targets, with none above it that does. It can grow as another starts, and never shrinks.
• The progress is the targets that ended. It never goes back, never passes the total, and is all of it once every step ended.
• When: at most once each mcpprogress.Interval, and at once when a step or a batch ends, but only when more targets ended. MCP asks that each notification has more progress than the last.
• A call that counts nothing sends nothing.

Fixed interfaces#

The interval, the rule that the progress only grows, and the words of the line (decision 27 and decision 32).