add built-in tool_active: list currently loaded/promoted tools

pkg/tools/execute/code.go

@@ -56,6 +56,8 @@ func (e *Server) Dispatch(ctx context.Context, name string, args json.RawMessage
 		return dispatchToolList(ctx, e, args)
 	case "tool_load":
 		return dispatchToolLoad(ctx, e, args)
+	case "tool_active":
+		return dispatchToolActive(ctx, e, args)
 	default:
 		return "", fmt.Errorf("unknown execute tool: %s", name)
 	}
@@ -192,3 +194,24 @@ func dispatchToolLoad(ctx context.Context, e *Server, args json.RawMessage) (str
 	}
 	return fmt.Sprintf("loaded: %s", a.Name), nil
 }
+
+// dispatchToolActive lists tools currently loaded (promoted) in this session.
+func dispatchToolActive(ctx context.Context, e *Server, args json.RawMessage) (string, error) {
+	if e.toolRegistry == nil || e.sessionID == "" {
+		return "(no tools loaded)", nil
+	}
+	loaded := e.toolRegistry.Loaded(e.sessionID)
+	if len(loaded) == 0 {
+		return "(no tools loaded)", nil
+	}
+	var out strings.Builder
+	for _, t := range loaded {
+		out.WriteString(t.Name)
+		if t.Description != "" {
+			out.WriteString(" — ")
+			out.WriteString(t.Description)
+		}
+		out.WriteString("\n")
+	}
+	return strings.TrimRight(out.String(), "\n"), nil
+}

pkg/tools/execute/server.go

@@ -176,6 +176,18 @@ After loading, the tool becomes a native callable function.`,
 				}
 			}`),
 		},
+		{
+			Name: "tool_active",
+			Description: `List tools currently loaded (promoted) in this session.
+
+Usage: (no arguments)
+
+Returns tools with descriptions, one per line.`,
+			InputSchema: json.RawMessage(`{
+				"type": "object",
+				"properties": {}
+			}`),
+		},
 	}
 
 	if e.toolRegistry != nil && e.sessionID != "" {