Add allow list for tool categories (#100)

Right now it is only possible to disable categories of tools which is
tedious for users who want to only use one or two categories, and means
that new tools added in the future will automatically show up. Add the
ability to also set an allow-list of tools that can then be overridden
using the --disable-<category> flags.

Author: csmarchbanks

cmd/mcp-grafana/main.go

@@ -6,23 +6,32 @@ import (
 	"fmt"
 	"log/slog"
 	"os"
+	"slices"
+	"strings"
 
 	"github.com/mark3labs/mcp-go/server"
 
 	mcpgrafana "github.com/grafana/mcp-grafana"
 	"github.com/grafana/mcp-grafana/tools"
 )
 
-func maybeAddTools(s *server.MCPServer, tf func(*server.MCPServer), disable bool, category string) {
+func maybeAddTools(s *server.MCPServer, tf func(*server.MCPServer), enabledTools []string, disable bool, category string) {
+	if !slices.Contains(enabledTools, category) {
+		slog.Debug("Not enabling tools", "category", category)
+		return
+	}
 	if disable {
 		slog.Info("Disabling tools", "category", category)
 		return
 	}
+	slog.Debug("Enabling tools", "category", category)
 	tf(s)
 }
 
 // disabledTools indicates whether each category of tools should be disabled.
 type disabledTools struct {
+	enabledTools string
+
 	search, datasource, incident,
 	prometheus, loki, alerting,
 	dashboard, oncall bool
@@ -35,6 +44,8 @@ type grafanaConfig struct {
 }
 
 func (dt *disabledTools) addFlags() {
+	flag.StringVar(&dt.enabledTools, "enabled-tools", "search,datasource,incident,prometheus,loki,alerting,dashboard,oncall", "A comma separated list of tools enabled for this server. Can be overwritten entirely or by disabling specific components, e.g. --disable-search.")
+
 	flag.BoolVar(&dt.search, "disable-search", false, "Disable search tools")
 	flag.BoolVar(&dt.datasource, "disable-datasource", false, "Disable datasource tools")
 	flag.BoolVar(&dt.incident, "disable-incident", false, "Disable incident tools")
@@ -50,14 +61,15 @@ func (gc *grafanaConfig) addFlags() {
 }
 
 func (dt *disabledTools) addTools(s *server.MCPServer) {
-	maybeAddTools(s, tools.AddSearchTools, dt.search, "search")
-	maybeAddTools(s, tools.AddDatasourceTools, dt.datasource, "datasource")
-	maybeAddTools(s, tools.AddIncidentTools, dt.incident, "incident")
-	maybeAddTools(s, tools.AddPrometheusTools, dt.prometheus, "prometheus")
-	maybeAddTools(s, tools.AddLokiTools, dt.loki, "loki")
-	maybeAddTools(s, tools.AddAlertingTools, dt.alerting, "alerting")
-	maybeAddTools(s, tools.AddDashboardTools, dt.dashboard, "dashboard")
-	maybeAddTools(s, tools.AddOnCallTools, dt.oncall, "oncall")
+	enabledTools := strings.Split(dt.enabledTools, ",")
+	maybeAddTools(s, tools.AddSearchTools, enabledTools, dt.search, "search")
+	maybeAddTools(s, tools.AddDatasourceTools, enabledTools, dt.datasource, "datasource")
+	maybeAddTools(s, tools.AddIncidentTools, enabledTools, dt.incident, "incident")
+	maybeAddTools(s, tools.AddPrometheusTools, enabledTools, dt.prometheus, "prometheus")
+	maybeAddTools(s, tools.AddLokiTools, enabledTools, dt.loki, "loki")
+	maybeAddTools(s, tools.AddAlertingTools, enabledTools, dt.alerting, "alerting")
+	maybeAddTools(s, tools.AddDashboardTools, enabledTools, dt.dashboard, "dashboard")
+	maybeAddTools(s, tools.AddOnCallTools, enabledTools, dt.oncall, "oncall")
 }
 
 func newServer(dt disabledTools) *server.MCPServer {