enhance: add discovery revision to server config

README.md

@@ -75,6 +75,13 @@ or called. Without overrides, all discovered tools are available. Set the server
 `disableTools: true` to expose no tools, regardless of overrides. Prompts and
 resources are unaffected.
 
+Each server accepts an optional `discoveryRevision` string (default empty, not
+interpolated). Set it to a fresh revision to trigger rediscovery when the updated
+configuration is next used. It changes the complete configuration fingerprint,
+so all components and feature lists are rediscovered and subsequent stateful
+calls use new downstream runtimes. Reusing an earlier value can reuse its cached
+catalog. The value is not sent to downstream servers.
+
 ## Running
 
 Build and run the HTTP frontend:

catalog/registry_test.go

@@ -52,6 +52,28 @@ func TestFingerprintIsStableCompleteAndSecretSafe(t *testing.T) {
 	}
 }
 
+func TestRegistryDiscoveryRevisionTriggersRediscovery(t *testing.T) {
+	discoverer := &countingDiscoverer{started: make(chan struct{}), release: make(chan struct{})}
+	close(discoverer.release)
+	registry := catalog.NewRegistry(discoverer)
+	defer registry.Close()
+	for i, field := range []string{"", "    discoveryRevision: revision-1\n"} {
+		cfg, err := config.Load([]byte("servers:\n  - name: fixture\n    url: https://example.invalid\n"+field), config.LoadOptions{})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for range 2 {
+			_, _, err := registry.Get(t.Context(), cfg)
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
+		if got := discoverer.Count(); got != i+1 {
+			t.Fatalf("discoveries = %d, want %d", got, i+1)
+		}
+	}
+}
+
 func TestRegistryDeduplicatesConcurrentCompilation(t *testing.T) {
 	discoverer := &countingDiscoverer{started: make(chan struct{}), release: make(chan struct{})}
 	registry := catalog.NewRegistry(discoverer)

config/config.go

@@ -15,6 +15,8 @@ type Config struct {
 
 // Server describes one component MCP server.
 type Server struct {
+	// DiscoveryRevision participates in the complete configuration fingerprint only.
+	DiscoveryRevision  string
 	Name               string
 	Prefix             string
 	URL                string
@@ -81,6 +83,7 @@ type configDTO struct {
 }
 
 type serverDTO struct {
+	DiscoveryRevision  string                        `yaml:"discoveryRevision"`
 	Name               string                        `yaml:"name"`
 	Prefix             string                        `yaml:"prefix"`
 	URL                string                        `yaml:"url"`

config/load.go

@@ -103,6 +103,7 @@ func (d configDTO) runtime(lookup func(string) (string, bool)) (*Config, error)
 
 func (d serverDTO) runtime(path string, lookup func(string) (string, bool)) (Server, error) {
 	server := Server{
+		DiscoveryRevision:  d.DiscoveryRevision,
 		Name:               strings.TrimSpace(d.Name),
 		Prefix:             d.Prefix,
 		Headers:            make(map[string]string, len(d.Headers)),