Show start-dev feature overrides in startup banner

internal/devserver/server.go

@@ -60,8 +60,28 @@ const (
 )
 
 type namespaceFeatureOverride struct {
-	setting dynamicconfig.NamespaceBoolSetting
-	enabled bool
+	setting     dynamicconfig.NamespaceBoolSetting
+	enabled     bool
+	feature     string
+	designation featureDesignation
+}
+
+type featureDesignation string
+
+const (
+	featureDesignationExperimental  featureDesignation = "Experimental"
+	featureDesignationPreRelease    featureDesignation = "Pre-release"
+	featureDesignationPublicPreview featureDesignation = "Public preview"
+)
+
+// StartDevFeatureOverride describes feature-specific dynamic config shown in the
+// `temporal server start-dev` banner.
+type StartDevFeatureOverride struct {
+	Feature        string
+	Designation    string
+	Key            string
+	Value          any
+	UserConfigured bool
 }
 
 // startDevServerFeatureOverrides contains temporary feature-specific dynamic config for
@@ -72,8 +92,40 @@ type namespaceFeatureOverride struct {
 // These values are applied without constraints and therefore affect every namespace.
 // NamespaceBoolSetting describes the server setting's lookup precedence, not override scope.
 var startDevServerFeatureOverrides = []namespaceFeatureOverride{
-	{setting: activity.EnableStandaloneActivityOperatorCommands, enabled: true},
-	{setting: dynamicconfig.FrontendEnableBatchOperationsForStandaloneActivities, enabled: true},
+	{
+		setting:     activity.EnableStandaloneActivityOperatorCommands,
+		enabled:     true,
+		feature:     "Standalone Activity operator commands",
+		designation: featureDesignationPublicPreview,
+	},
+	{
+		setting:     dynamicconfig.FrontendEnableBatchOperationsForStandaloneActivities,
+		enabled:     true,
+		feature:     "Standalone Activity batch operations",
+		designation: featureDesignationPublicPreview,
+	},
+}
+
+// StartDevFeatureOverrides returns the effective feature-specific configuration for display.
+func (s *StartOptions) StartDevFeatureOverrides() []StartDevFeatureOverride {
+	overrides := make([]StartDevFeatureOverride, 0, len(startDevServerFeatureOverrides))
+	for _, override := range startDevServerFeatureOverrides {
+		key := override.setting.Key().String()
+		value := any(override.enabled)
+		userConfigured := false
+		if configuredValue, ok := s.DynamicConfigValues[key]; ok {
+			value = configuredValue
+			userConfigured = true
+		}
+		overrides = append(overrides, StartDevFeatureOverride{
+			Feature:        override.feature,
+			Designation:    string(override.designation),
+			Key:            key,
+			Value:          value,
+			UserConfigured: userConfigured,
+		})
+	}
+	return overrides
 }
 
 type StartOptions struct {

internal/devserver/server_test.go

@@ -11,6 +11,14 @@ func TestStartDevServerFeatureOverridesMatchServerDefaults(t *testing.T) {
 	for _, override := range startDevServerFeatureOverrides {
 		key := override.setting.Key().String()
 		t.Run(key, func(t *testing.T) {
+			if override.feature == "" {
+				t.Fatal("feature name must not be empty")
+			}
+			switch override.designation {
+			case featureDesignationExperimental, featureDesignationPreRelease, featureDesignationPublicPreview:
+			default:
+				t.Fatalf("invalid feature designation %q", override.designation)
+			}
 			if serverDefault := override.setting.Get(dc)("default"); serverDefault == override.enabled {
 				t.Fatalf("%q now defaults to %t; remove its feature override", key, override.enabled)
 			}

internal/temporalcli/commands.server.go

@@ -175,6 +175,15 @@ func (t *TemporalServerStartDevCommand) run(cctx *CommandContext, args []string)
 		cctx.Printer.Printlnf("%-21s http://%v:%v%v", "Temporal UI:", toFriendlyIp(opts.UIIP), opts.UIPort, opts.PublicPath)
 	}
 	cctx.Printer.Printlnf("%-21s http://%v:%v/metrics", "Temporal Metrics:", toFriendlyIp(opts.FrontendIP), opts.MetricsPort)
+	cctx.Printer.Printlnf("Temporal Features:")
+	for _, override := range opts.StartDevFeatureOverrides() {
+		source := "built-in"
+		if override.UserConfigured {
+			source = "user override"
+		}
+		cctx.Printer.Printlnf("  %-14s %-37s %s=%v (%s)",
+			override.Designation, override.Feature, override.Key, override.Value, source)
+	}
 	<-cctx.Done()
 	if !t.Parent.Parent.LogLevel.ChangedFromDefault {
 		// The server routinely emits various warnings on shutdown.

internal/temporalcli/commands.server_test.go

@@ -19,6 +19,8 @@ import (
 	"go.temporal.io/api/operatorservice/v1"
 	"go.temporal.io/sdk/client"
 	"go.temporal.io/sdk/temporal"
+	serveractivity "go.temporal.io/server/chasm/lib/activity"
+	"go.temporal.io/server/common/dynamicconfig"
 )
 
 // TODO(cretz): To test:
@@ -328,7 +330,10 @@ func TestServer_StartDev_BannerPersistenceInMemory(t *testing.T) {
 	httpPort := strconv.Itoa(devserver.MustGetFreePort("127.0.0.1"))
 	resCh := make(chan *CommandResult, 1)
 	go func() {
-		resCh <- h.Execute("server", "start-dev", "-p", port, "--http-port", httpPort, "--headless")
+		resCh <- h.Execute(
+			"server", "start-dev", "-p", port, "--http-port", httpPort, "--headless",
+			"--dynamic-config-value", serveractivity.EnableStandaloneActivityOperatorCommands.Key().String()+"=false",
+		)
 	}()
 
 	// Wait until the server is dial-able, then cancel
@@ -357,6 +362,10 @@ func TestServer_StartDev_BannerPersistenceInMemory(t *testing.T) {
 	out := res.Stdout.String()
 	h.Contains(out, "Temporal Persistence:")
 	h.Contains(out, "in-memory")
+	h.Contains(out, "Temporal Features:")
+	h.Contains(out, "Public preview")
+	h.Contains(out, serveractivity.EnableStandaloneActivityOperatorCommands.Key().String()+"=false (user override)")
+	h.Contains(out, dynamicconfig.FrontendEnableBatchOperationsForStandaloneActivities.Key().String()+"=true (built-in)")
 }
 
 func TestServer_StartDev_BannerPersistenceFile(t *testing.T) {