feat(mcp): emit channel events for brain recall/remember

DirectSubsystem pushes brain.recall.complete and brain.remember.complete
events via OnChannel callback. Avoids circular import by using func-based
wiring instead of interface-based SubsystemWithNotifier.

New() auto-detects subsystems with OnChannel() and wires them to
ChannelSend via closure.

Co-Authored-By: Virgil <virgil@lethean.io>

pkg/mcp/brain/direct.go

@@ -18,13 +18,27 @@ import (
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
+// channelSender is the callback for pushing channel events.
+type channelSender func(ctx context.Context, channel string, data any)
+
 // DirectSubsystem implements mcp.Subsystem for OpenBrain via direct HTTP calls.
 // Unlike Subsystem (which uses the IDE WebSocket bridge), this calls the
 // Laravel API directly — suitable for standalone core-mcp usage.
 type DirectSubsystem struct {
-	apiURL string
-	apiKey string
-	client *http.Client
+	apiURL    string
+	apiKey    string
+	client    *http.Client
+	onChannel channelSender
+}
+
+// OnChannel sets a callback for channel event broadcasting.
+// Called by the MCP service after creation to wire up notifications.
+//
+//	brain.OnChannel(func(ctx context.Context, ch string, data any) {
+//	    mcpService.ChannelSend(ctx, ch, data)
+//	})
+func (s *DirectSubsystem) OnChannel(fn func(ctx context.Context, channel string, data any)) {
+	s.onChannel = fn
 }
 
 // NewDirect creates a brain subsystem that calls the OpenBrain API directly.
@@ -132,6 +146,13 @@ func (s *DirectSubsystem) remember(ctx context.Context, _ *mcp.CallToolRequest,
 	}
 
 	id, _ := result["id"].(string)
+	if s.onChannel != nil {
+		s.onChannel(ctx, "brain.remember.complete", map[string]any{
+			"id":      id,
+			"type":    input.Type,
+			"project": input.Project,
+		})
+	}
 	return nil, RememberOutput{
 		Success:   true,
 		MemoryID:  id,
@@ -185,6 +206,12 @@ func (s *DirectSubsystem) recall(ctx context.Context, _ *mcp.CallToolRequest, in
 		}
 	}
 
+	if s.onChannel != nil {
+		s.onChannel(ctx, "brain.recall.complete", map[string]any{
+			"query": input.Query,
+			"count": len(memories),
+		})
+	}
 	return nil, RecallOutput{
 		Success:  true,
 		Count:    len(memories),

pkg/mcp/mcp.go

@@ -107,6 +107,19 @@ func New(opts Options) (*Service, error) {
 
 	for _, sub := range s.subsystems {
 		sub.RegisterTools(s.server)
+		if sn, ok := sub.(SubsystemWithNotifier); ok {
+			sn.SetNotifier(s)
+		}
+		// Wire channel callback for subsystems that use func-based notification
+		type channelWirer interface {
+			OnChannel(func(ctx context.Context, channel string, data any))
+		}
+		if cw, ok := sub.(channelWirer); ok {
+			svc := s // capture for closure
+			cw.OnChannel(func(ctx context.Context, channel string, data any) {
+				svc.ChannelSend(ctx, channel, data)
+			})
+		}
 	}
 
 	return s, nil