Every serving principal may answer the services discovery for what it serves; the controller announces its seat (hq ADR 0197)

Grants: a principal that serves tools subscribes $SRV.PING/$SRV.INFO and those questions under
each name it serves — its own and no other's; the tool runtime and people may ask. The controller
answers discovery for the mesh-controller seat in NATS's services format, one endpoint per verb it
serves, with the seat's description and schema. module list --json says which modules declare tools,
so the console expects an announcement only from those.

cmd/mesh-controller/seatverbs_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"github.com/novox/mesh-controller/internal/link"
 	"strings"
 	"testing"
 
@@ -264,3 +265,30 @@ func TestTheNodesAndModulesVerbsAnswerAsJSON(t *testing.T) {
 		}
 	}
 }
+
+// novox/hq ADR 0197: the controller announces exactly the verbs it serves, each on the subject and
+// queue it serves it on, with the seat's own description and schema, in NATS's services format.
+func TestTheControllerAnnouncesTheVerbsItServes(t *testing.T) {
+	handlers, _, err := seatToolHandlers()
+	if err != nil {
+		t.Fatal(err)
+	}
+	info := seatAnnouncement(handlers)
+	if info.Name != catalogue.ControllerSeatName || info.ID == "" || info.Version == "" {
+		t.Fatalf("the service is not named for the seat: %+v", info.ServiceIdentity)
+	}
+	if len(info.Endpoints) != len(handlers) {
+		t.Fatalf("%d endpoints announced for %d verbs served", len(info.Endpoints), len(handlers))
+	}
+	for _, e := range info.Endpoints {
+		if _, served := handlers[e.Name]; !served {
+			t.Errorf("%s is announced and not served", e.Name)
+		}
+		if e.Subject != link.SeatToolSubject(catalogue.ControllerSeatName, e.Name) || e.QueueGroup != "seat."+catalogue.ControllerSeatName {
+			t.Errorf("%s is announced on %s/%s, not where it is served", e.Name, e.Subject, e.QueueGroup)
+		}
+		if e.Metadata["description"] == "" || e.Metadata["schema"] == "" || e.Metadata["scope"] != "mesh" {
+			t.Errorf("%s is announced without its description, schema or scope: %v", e.Name, e.Metadata)
+		}
+	}
+}