Add opt-in issuer-owned access-token status and scoped revocation

Assistant: codex
Assistant-Model: gpt-6.1-sol
Assistant-Session: 01a14bfc-9643-7872-aa12-98326dcf25e7

src/cmd/keycape/main.go

@@ -149,6 +149,24 @@ func main() {
 	// 12. Register HTTP handlers.
 	// -----------------------------------------------------------------
 	mux := http.NewServeMux()
+	var tokenStatus *oidc.TokenStatusStore
+	var introspectionEndpoint, revocationEndpoint string
+	if cfg.TokenStatus.Enabled {
+		limit := cfg.TokenStatus.MaxEntries
+		if limit == 0 {
+			limit = 10000
+		}
+		var err error
+		tokenStatus, err = oidc.NewTokenStatusStore(limit)
+		if err != nil {
+			log.Error().Msg("invalid token-status configuration")
+			os.Exit(1)
+		}
+		status := &oidc.TokenStatusHandler{Tokens: tokenStatus, ClientConfig: clients, Users: lldapAdapter, SigningKey: &privateKey.PublicKey, Issuer: issuer}
+		mux.HandleFunc("/introspect", status.Introspect)
+		mux.HandleFunc("/revoke", status.Revoke)
+		introspectionEndpoint, revocationEndpoint = issuer+"/introspect", issuer+"/revoke"
+	}
 
 	// Discovery.
 	mux.Handle("/.well-known/openid-configuration", oidc.NewDiscoveryHandler(oidc.DiscoveryConfig{
@@ -158,6 +176,8 @@ func main() {
 		JWKSUri:               issuer + "/jwks",
 		UserinfoEndpoint:      issuer + "/userinfo",
 		EndSessionEndpoint:    issuer + "/logout",
+		IntrospectionEndpoint: introspectionEndpoint,
+		RevocationEndpoint:    revocationEndpoint,
 		Clients:               clients,
 	}))
 
@@ -218,15 +238,18 @@ func main() {
 		// fails open, so a configured-but-unreachable cache omits the claim
 		// rather than failing issuance.
 		TenantEngine: buildTenantEngine(cfg.TenantEngine),
+		Tokens:       tokenStatus,
 	}
 	mux.Handle("/token", enforcement.Middleware(tokenHandler))
 
 	// Userinfo handler.
 	mux.Handle("/userinfo", &oidc.UserinfoHandler{
-		Users:      lldapAdapter,
-		SigningKey: &privateKey.PublicKey,
-		Issuer:     issuer,
-		Emitter:    emitter,
+		Users:        lldapAdapter,
+		SigningKey:   &privateKey.PublicKey,
+		Issuer:       issuer,
+		Emitter:      emitter,
+		Tokens:       tokenStatus,
+		ClientConfig: clients,
 	})
 
 	// Healthz.

src/internal/config/config.go

@@ -30,6 +30,14 @@ type Config struct {
 	Clients          []ClientConfig     `yaml:"clients"`
 	Environment      string             `yaml:"environment"`
 	TenantEngine     TenantEngineConfig `yaml:"tenantEngine,omitempty"`
+	TokenStatus      TokenStatusConfig  `yaml:"tokenStatus,omitempty"`
+}
+
+// TokenStatusConfig opts a singleton issuer into online access-token status.
+// Existing deployment configuration remains expiry-only until owner admission.
+type TokenStatusConfig struct {
+	Enabled    bool `yaml:"enabled"`
+	MaxEntries int  `yaml:"maxEntries,omitempty"`
 }
 
 // TenantEngineConfig configures the optional tenant_roles cache claim.

src/internal/config/token_status_test.go

@@ -0,0 +1,41 @@
+package config_test
+
+import (
+	"strings"
+	"testing"
+
+	"keycape/internal/config"
+)
+
+func TestTokenStatusConfigIsExplicitBoundedAndHTTPS(t *testing.T) {
+	for _, kind := range []string{"legacy", "enabled-default", "enabled-bounded", "http", "userinfo-url", "query", "too-large", "negative", "disabled-capacity"} {
+		t.Run(kind, func(t *testing.T) {
+			cfg := validConfig("unused-public-test-key-path")
+			cfg.TokenStatus.Enabled = kind != "legacy" && kind != "disabled-capacity"
+			switch kind {
+			case "enabled-bounded":
+				cfg.TokenStatus.MaxEntries = 128
+			case "http":
+				cfg.Issuer = "http://auth.example.com"
+			case "userinfo-url":
+				cfg.Issuer = "https://name@auth.example.com"
+			case "query":
+				cfg.Issuer = "https://auth.example.com?query=present"
+			case "too-large":
+				cfg.TokenStatus.MaxEntries = 1000001
+			case "negative":
+				cfg.TokenStatus.MaxEntries = -1
+			case "disabled-capacity":
+				cfg.TokenStatus.MaxEntries = 128
+			}
+			var statusError bool
+			for _, err := range config.ValidateConfig(cfg) {
+				statusError = statusError || strings.HasPrefix(err, "tokenStatus")
+			}
+			expected := kind != "legacy" && kind != "enabled-default" && kind != "enabled-bounded"
+			if statusError != expected {
+				t.Fatal("token-status configuration acceptance mismatch")
+			}
+		})
+	}
+}

src/internal/config/validate.go

@@ -12,6 +12,17 @@ import (
 // Called at startup — the server must exit 1 if any errors are returned.
 func ValidateConfig(cfg *Config) []string {
 	var errs []string
+	if cfg.TokenStatus.Enabled {
+		u, err := url.Parse(cfg.Issuer)
+		if err != nil || u.Scheme != "https" || u.Hostname() == "" || u.User != nil || u.RawQuery != "" || u.Fragment != "" {
+			errs = append(errs, "tokenStatus: requires an HTTPS issuer without credentials, query or fragment")
+		}
+		if cfg.TokenStatus.MaxEntries < 0 || cfg.TokenStatus.MaxEntries > 1000000 {
+			errs = append(errs, "tokenStatus.maxEntries: must be between 1 and 1000000, or omitted for 10000")
+		}
+	} else if cfg.TokenStatus.MaxEntries != 0 {
+		errs = append(errs, "tokenStatus.maxEntries: set while token status is disabled")
+	}
 	for name, raw := range map[string]string{"accountPortalURL": cfg.AccountPortalURL, "browserLogoutURL": cfg.BrowserLogoutURL} {
 		if raw == "" {
 			continue

src/internal/server/oidc/discovery.go

@@ -20,6 +20,8 @@ type DiscoveryConfig struct {
 	JWKSUri               string
 	UserinfoEndpoint      string // optional, empty = not advertised
 	EndSessionEndpoint    string // optional, empty = not advertised
+	IntrospectionEndpoint string // opt-in online access-token status
+	RevocationEndpoint    string // opt-in access-token revocation
 	// Clients supplies the registered clients so scopes_supported reflects the
 	// scopes this deployment can actually grant, rather than a fixed list that
 	// omits every configured resource scope (KEY-WP-0017-T03). Nil or empty
@@ -31,22 +33,26 @@ type DiscoveryConfig struct {
 // Fields are ordered to match common OIDC implementations for readability.
 // registration_endpoint is intentionally absent — no dynamic client registration.
 type discoveryDocument struct {
-	Issuer                            string   `json:"issuer"`
-	AuthorizationEndpoint             string   `json:"authorization_endpoint"`
-	TokenEndpoint                     string   `json:"token_endpoint"`
-	JWKSUri                           string   `json:"jwks_uri"`
-	UserinfoEndpoint                  string   `json:"userinfo_endpoint,omitempty"`
-	EndSessionEndpoint                string   `json:"end_session_endpoint,omitempty"`
-	ResponseTypesSupported            []string `json:"response_types_supported"`
-	GrantTypesSupported               []string `json:"grant_types_supported"`
-	CodeChallengeMethodsSupported     []string `json:"code_challenge_methods_supported"`
-	IDTokenSigningAlgValuesSupported  []string `json:"id_token_signing_alg_values_supported"`
-	ScopesSupported                   []string `json:"scopes_supported"`
-	TokenEndpointAuthMethodsSupported []string `json:"token_endpoint_auth_methods_supported"`
-	ClaimsSupported                   []string `json:"claims_supported"`
-	SubjectTypesSupported             []string `json:"subject_types_supported"`
-	RequestParameterSupported         bool     `json:"request_parameter_supported"`
-	ClaimsParameterSupported          bool     `json:"claims_parameter_supported"`
+	Issuer                                    string   `json:"issuer"`
+	AuthorizationEndpoint                     string   `json:"authorization_endpoint"`
+	TokenEndpoint                             string   `json:"token_endpoint"`
+	JWKSUri                                   string   `json:"jwks_uri"`
+	UserinfoEndpoint                          string   `json:"userinfo_endpoint,omitempty"`
+	EndSessionEndpoint                        string   `json:"end_session_endpoint,omitempty"`
+	IntrospectionEndpoint                     string   `json:"introspection_endpoint,omitempty"`
+	RevocationEndpoint                        string   `json:"revocation_endpoint,omitempty"`
+	IntrospectionEndpointAuthMethodsSupported []string `json:"introspection_endpoint_auth_methods_supported,omitempty"`
+	RevocationEndpointAuthMethodsSupported    []string `json:"revocation_endpoint_auth_methods_supported,omitempty"`
+	ResponseTypesSupported                    []string `json:"response_types_supported"`
+	GrantTypesSupported                       []string `json:"grant_types_supported"`
+	CodeChallengeMethodsSupported             []string `json:"code_challenge_methods_supported"`
+	IDTokenSigningAlgValuesSupported          []string `json:"id_token_signing_alg_values_supported"`
+	ScopesSupported                           []string `json:"scopes_supported"`
+	TokenEndpointAuthMethodsSupported         []string `json:"token_endpoint_auth_methods_supported"`
+	ClaimsSupported                           []string `json:"claims_supported"`
+	SubjectTypesSupported                     []string `json:"subject_types_supported"`
+	RequestParameterSupported                 bool     `json:"request_parameter_supported"`
+	ClaimsParameterSupported                  bool     `json:"claims_parameter_supported"`
 }
 
 // discoveryHandler implements http.Handler for GET /.well-known/openid-configuration.
@@ -85,6 +91,15 @@ func NewDiscoveryHandler(cfg DiscoveryConfig) http.Handler {
 		RequestParameterSupported: false,
 		ClaimsParameterSupported:  false,
 	}
+	if cfg.IntrospectionEndpoint != "" {
+		d.IntrospectionEndpoint = cfg.IntrospectionEndpoint
+		d.IntrospectionEndpointAuthMethodsSupported = []string{"client_secret_basic"}
+		d.ClaimsSupported = append(d.ClaimsSupported, "jti")
+	}
+	if cfg.RevocationEndpoint != "" {
+		d.RevocationEndpoint = cfg.RevocationEndpoint
+		d.RevocationEndpointAuthMethodsSupported = []string{"client_secret_basic", "none"}
+	}
 
 	b, err := json.Marshal(d)
 	if err != nil {

src/internal/server/oidc/token.go

@@ -32,6 +32,9 @@ type TokenHandler struct {
 	// TenantEngine sources the optional tenant_roles claim (KEY-WP-0005-T02).
 	// Nil disables it entirely -- token issuance never depends on it.
 	TenantEngine *tenantengine.Client
+	// Tokens enables issuer-owned online token status; nil retains the legacy
+	// expiry-only profile. Enabling it requires explicit deployment admission.
+	Tokens *TokenStatusStore
 }
 
 // tokenResponse is the JSON body returned on a successful token exchange.
@@ -233,11 +236,25 @@ func (h *TokenHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		claims["aud"] = audience
 	}
 	claims["scope"] = strings.Join(sess.Scopes, " ")
+	if h.Tokens != nil {
+		id := make([]byte, 32)
+		if _, err := rand.Read(id); err != nil {
+			http.Error(w, "token status unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		claims["jti"] = base64.RawURLEncoding.EncodeToString(id)
+	}
 	accessToken, err := buildJWT(claims, kid, h.SigningKey)
 	if err != nil {
 		http.Error(w, "failed to build JWT", http.StatusInternalServerError)
 		return
 	}
+	if h.Tokens != nil {
+		if err := h.Tokens.register(accessToken, client, time.Unix(exp.Unix(), 0), now); err != nil {
+			http.Error(w, "token status unavailable", http.StatusServiceUnavailable)
+			return
+		}
+	}
 
 	// 8. Build response. The session was already consumed at lookup, so no
 	// separate replay-prevention delete is needed here.
@@ -357,11 +374,25 @@ func (h *TokenHandler) serveClientCredentials(w http.ResponseWriter, r *http.Req
 	if roles, ok := h.TenantEngine.Roles(ctx, client.Tenant); ok {
 		claims["tenant_roles"] = roles
 	}
+	if h.Tokens != nil {
+		id := make([]byte, 32)
+		if _, err := rand.Read(id); err != nil {
+			http.Error(w, "token status unavailable", http.StatusServiceUnavailable)
+			return
+		}
+		claims["jti"] = base64.RawURLEncoding.EncodeToString(id)
+	}
 	jwtToken, err := buildJWT(claims, "key-1", h.SigningKey)
 	if err != nil {
 		http.Error(w, "failed to build JWT", http.StatusInternalServerError)
 		return
 	}
+	if h.Tokens != nil {
+		if err := h.Tokens.register(jwtToken, client, time.Unix(now.Add(tokenLifetime).Unix(), 0), now); err != nil {
+			http.Error(w, "token status unavailable", http.StatusServiceUnavailable)
+			return
+		}
+	}
 	h.Emitter.Emit(ctx, telemetry.Event{
 		Timestamp: now, EventType: telemetry.EventTokenIssued, ClientID: clientID,
 		Endpoint: "/token", Result: "success", Scopes: requestedScopes,

src/internal/server/oidc/token_status.go

@@ -0,0 +1,97 @@
+package oidc
+
+import (
+	"crypto/sha256"
+	"encoding/json"
+	"errors"
+	"sync"
+	"time"
+
+	"keycape/internal/domain"
+)
+
+// TokenStatusStore is the optional single-process online access-token ledger.
+// It holds only token hashes and registration commitments, never bearer values.
+// Losing this store makes every previously issued token inactive to online
+// checks. It is not a browser session, approval, or operation authority store.
+type TokenStatusStore struct {
+	mu      sync.Mutex
+	entries map[[32]byte]tokenStatus
+	limit   int
+}
+
+type tokenStatus struct {
+	clientID     string
+	registration [32]byte
+	expires      time.Time
+	revoked      bool
+}
+
+func NewTokenStatusStore(limit int) (*TokenStatusStore, error) {
+	if limit < 1 || limit > 1000000 {
+		return nil, errors.New("invalid token-status capacity")
+	}
+	return &TokenStatusStore{entries: make(map[[32]byte]tokenStatus), limit: limit}, nil
+}
+
+func registrationCommitment(client *domain.Client) [32]byte {
+	// ClientSecret and TokenLifetime are deliberately omitted from Client JSON.
+	// Bind their commitments explicitly as well as all public registration data.
+	secret := sha256.Sum256([]byte(client.ClientSecret))
+	raw, _ := json.Marshal(struct {
+		Client   *domain.Client
+		Secret   [32]byte
+		Lifetime time.Duration
+	}{client, secret, client.TokenLifetime})
+	return sha256.Sum256(raw)
+}
+
+func (s *TokenStatusStore) register(raw string, client *domain.Client, expires, now time.Time) error {
+	if s == nil || client == nil || raw == "" || len(raw) > 32768 || !now.Before(expires) {
+		return errors.New("token-status registration refused")
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for key, entry := range s.entries {
+		if !now.Before(entry.expires) {
+			delete(s.entries, key)
+		}
+	}
+	key := sha256.Sum256([]byte(raw))
+	if _, exists := s.entries[key]; exists || len(s.entries) >= s.limit {
+		return errors.New("token-status registration refused")
+	}
+	s.entries[key] = tokenStatus{clientID: client.ClientID, registration: registrationCommitment(client), expires: expires}
+	return nil
+}
+
+func (s *TokenStatusStore) active(raw string, clients map[string]*domain.Client, now time.Time) (string, bool) {
+	if s == nil {
+		return "", false
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	entry, ok := s.entries[sha256.Sum256([]byte(raw))]
+	if !ok || entry.revoked || !now.Before(entry.expires) {
+		return "", false
+	}
+	client := clients[entry.clientID]
+	if client == nil || client.ClientID != entry.clientID || registrationCommitment(client) != entry.registration {
+		return "", false
+	}
+	return entry.clientID, true
+}
+
+func (s *TokenStatusStore) revoke(raw, clientID string) {
+	if s == nil {
+		return
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	key := sha256.Sum256([]byte(raw))
+	if entry, ok := s.entries[key]; ok && entry.clientID == clientID {
+		// Retain the tombstone until expiry: a retry can never reactivate it.
+		entry.revoked = true
+		s.entries[key] = entry
+	}
+}

src/internal/server/oidc/token_status_discovery_test.go

@@ -0,0 +1,30 @@
+package oidc_test
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"keycape/internal/server/oidc"
+)
+
+func TestTokenStatusDiscoveryOnlyAdvertisesEnabledProfile(t *testing.T) {
+	for _, enabled := range []bool{false, true} {
+		cfg := oidc.DiscoveryConfig{Issuer: "https://issuer.example"}
+		if enabled {
+			cfg.IntrospectionEndpoint, cfg.RevocationEndpoint = cfg.Issuer+"/introspect", cfg.Issuer+"/revoke"
+		}
+		w := httptest.NewRecorder()
+		oidc.NewDiscoveryHandler(cfg).ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/.well-known/openid-configuration", nil))
+		var doc map[string]interface{}
+		if json.Unmarshal(w.Body.Bytes(), &doc) != nil {
+			t.Fatal("discovery is invalid JSON")
+		}
+		for _, name := range []string{"introspection_endpoint", "revocation_endpoint", "introspection_endpoint_auth_methods_supported", "revocation_endpoint_auth_methods_supported"} {
+			if _, exists := doc[name]; exists != enabled {
+				t.Fatal("unimplemented token status advertised")
+			}
+		}
+	}
+}

src/internal/server/oidc/token_status_http.go

@@ -0,0 +1,145 @@
+package oidc
+
+import (
+	"crypto/rsa"
+	"encoding/json"
+	"mime"
+	"net/http"
+	"time"
+
+	"keycape/internal/domain"
+)
+
+// TokenStatusHandler serves the optional issuer-owned RFC 7662 introspection
+// and RFC 7009 revocation endpoints. Introspection authenticates the issuing
+// confidential client; this profile does not delegate cross-client token reads.
+type TokenStatusHandler struct {
+	Tokens       *TokenStatusStore
+	ClientConfig map[string]*domain.Client
+	Users        domain.UserRepository
+	SigningKey   *rsa.PublicKey
+	Issuer       string
+}
+
+func statusError(w http.ResponseWriter, status int, code string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Cache-Control", "no-store")
+	w.Header().Set("Pragma", "no-cache")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(map[string]string{"error": code})
+}
+
+func (h *TokenStatusHandler) parse(w http.ResponseWriter, r *http.Request, introspection bool) (*domain.Client, string, bool) {
+	w.Header().Set("Cache-Control", "no-store")
+	w.Header().Set("Pragma", "no-cache")
+	if r.Method != http.MethodPost {
+		w.Header().Set("Allow", "POST")
+		statusError(w, http.StatusMethodNotAllowed, "invalid_request")
+		return nil, "", false
+	}
+	if h.Tokens == nil || h.SigningKey == nil || h.Issuer == "" {
+		statusError(w, http.StatusServiceUnavailable, "temporarily_unavailable")
+		return nil, "", false
+	}
+	media, _, err := mime.ParseMediaType(r.Header.Get("Content-Type"))
+	if err != nil || media != "application/x-www-form-urlencoded" || r.URL.RawQuery != "" || len(r.Header.Values("Authorization")) > 1 {
+		statusError(w, http.StatusBadRequest, "invalid_request")
+		return nil, "", false
+	}
+	r.Body = http.MaxBytesReader(w, r.Body, 65536)
+	if err := r.ParseForm(); err != nil {
+		statusError(w, http.StatusBadRequest, "invalid_request")
+		return nil, "", false
+	}
+	for _, values := range r.PostForm {
+		if len(values) != 1 {
+			statusError(w, http.StatusBadRequest, "invalid_request")
+			return nil, "", false
+		}
+	}
+	raw := r.PostForm.Get("token")
+	if raw == "" || len(raw) > 32768 {
+		statusError(w, http.StatusBadRequest, "invalid_request")
+		return nil, "", false
+	}
+	id, secret, basic := basicClientCredentials(r)
+	formID := r.PostForm.Get("client_id")
+	if !basic {
+		id = formID
+	}
+	client := h.ClientConfig[id]
+	valid := client != nil && client.ClientID == id && !r.PostForm.Has("client_secret")
+	if valid && client.ClientType == "confidential" {
+		valid = basic && (formID == "" || formID == id) && client.ClientSecret != "" && secretsEqual(secret, client.ClientSecret)
+	} else {
+		// Public-client revocation requires possession of its own bearer token.
+		// Public clients can never enumerate token status via introspection.
+		valid = valid && !introspection && client.ClientType == "public" && !basic && r.Header.Get("Authorization") == ""
+	}
+	if !valid {
+		w.Header().Set("WWW-Authenticate", `Basic realm="keycape-token-status"`)
+		statusError(w, http.StatusUnauthorized, "invalid_client")
+		return nil, "", false
+	}
+	return client, raw, true
+}
+
+func (h *TokenStatusHandler) Introspect(w http.ResponseWriter, r *http.Request) {
+	client, raw, ok := h.parse(w, r, true)
+	if !ok {
+		return
+	}
+	response := map[string]interface{}{"active": false}
+	defer func() {
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(response)
+	}()
+	id, active := h.Tokens.active(raw, h.ClientConfig, time.Now())
+	if !active || id != client.ClientID {
+		return
+	}
+	claims, err := validateAccessToken(raw, h.SigningKey, h.Issuer)
+	if err != nil {
+		return
+	}
+	sub, _ := claims["sub"].(string)
+	switch claims["principal_type"] {
+	case "human":
+		if h.Users == nil {
+			return
+		}
+		user, err := lookupUserBySubject(r.Context(), h.Users, claims, sub)
+		if err != nil || !user.Enabled || isSuspended(user) {
+			return
+		}
+	case "service":
+		if sub == "" || sub != client.ServiceSubject {
+			return
+		}
+	default:
+		return
+	}
+	// Directory lookup may block. Recheck revocation and registration after it.
+	if current, active := h.Tokens.active(raw, h.ClientConfig, time.Now()); !active || current != id {
+		return
+	}
+	response["active"] = true
+	response["client_id"] = id
+	response["token_type"] = "Bearer"
+	for _, field := range []string{"iss", "sub", "aud", "scope", "iat", "exp", "jti"} {
+		if value, present := claims[field]; present {
+			response[field] = value
+		}
+	}
+}
+
+func (h *TokenStatusHandler) Revoke(w http.ResponseWriter, r *http.Request) {
+	client, raw, ok := h.parse(w, r, false)
+	if !ok {
+		return
+	}
+	// Unknown, expired, ID and other-client tokens receive the same empty
+	// success as an already-revoked token; no existence information leaks.
+	h.Tokens.revoke(raw, client.ClientID)
+	w.WriteHeader(http.StatusOK)
+}

src/internal/server/oidc/token_status_internal_test.go

@@ -0,0 +1,66 @@
+package oidc
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"keycape/internal/domain"
+)
+
+func TestTokenStatusExactExpiryCapacityAndTombstones(t *testing.T) {
+	client := &domain.Client{ClientID: "synthetic-client", ClientType: "public"}
+	clients := map[string]*domain.Client{client.ClientID: client}
+	store, _ := NewTokenStatusStore(1)
+	now := time.Unix(1700000000, 0)
+	end := now.Add(time.Second)
+	if store.register("synthetic-first", client, end, now) != nil {
+		t.Fatal("register refused")
+	}
+	if _, active := store.active("synthetic-first", clients, end); active {
+		t.Fatal("expiry equality accepted")
+	}
+	store.revoke("synthetic-first", client.ClientID)
+	if store.register("synthetic-first", client, end, now) == nil {
+		t.Fatal("revoked token reactivated")
+	}
+	if store.register("synthetic-second", client, end.Add(time.Second), end) != nil {
+		t.Fatal("expired tombstone not collected")
+	}
+	if _, active := store.active("synthetic-second", clients, end); !active {
+		t.Fatal("fresh token refused")
+	}
+	for _, capacity := range []int{-1, 0, 1000001} {
+		if _, err := NewTokenStatusStore(capacity); err == nil {
+			t.Fatal("unbounded capacity accepted")
+		}
+	}
+}
+
+func TestTokenStatusConcurrentIssueReadAndRevoke(t *testing.T) {
+	store, _ := NewTokenStatusStore(128)
+	client := &domain.Client{ClientID: "synthetic-client", ClientType: "public"}
+	clients := map[string]*domain.Client{client.ClientID: client}
+	now := time.Now()
+	var wg sync.WaitGroup
+	for i := 0; i < 64; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			raw := fmt.Sprintf("synthetic-token-%d", i)
+			if store.register(raw, client, now.Add(time.Minute), now) != nil {
+				t.Error("concurrent registration failed")
+				return
+			}
+			if _, active := store.active(raw, clients, now); !active {
+				t.Error("concurrent current token refused")
+			}
+			store.revoke(raw, client.ClientID)
+			if _, active := store.active(raw, clients, now); active {
+				t.Error("concurrent revoked token accepted")
+			}
+		}(i)
+	}
+	wg.Wait()
+}

src/internal/server/oidc/token_status_test.go

@@ -0,0 +1,379 @@
+package oidc_test
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+
+	"keycape/internal/domain"
+	"keycape/internal/server/oidc"
+	"keycape/internal/server/telemetry"
+)
+
+type statusFixture struct {
+	token    *oidc.TokenHandler
+	status   *oidc.TokenStatusHandler
+	userinfo *oidc.UserinfoHandler
+	users    *mockUserRepo
+}
+
+func newStatusFixture(t *testing.T, capacity int) *statusFixture {
+	t.Helper()
+	users := &mockUserRepo{users: map[string]*domain.User{"alice": aliceUser()}}
+	tokens, err := oidc.NewTokenStatusStore(capacity)
+	if err != nil {
+		t.Fatal("store creation failed")
+	}
+	h, key := newTokenHandler(t, oidc.NewSessionStore(), users)
+	h.Tokens = tokens
+	h.ClientConfig["test-client"].ClientType = "confidential"
+	h.ClientConfig["test-client"].ClientSecret = "synthetic-status-only"
+	h.ClientConfig["other"] = &domain.Client{ClientID: "other", ClientType: "confidential", ClientSecret: "synthetic-other-only"}
+	return &statusFixture{token: h, users: users,
+		status:   &oidc.TokenStatusHandler{Tokens: tokens, ClientConfig: h.ClientConfig, Users: users, SigningKey: &key.PublicKey, Issuer: h.Issuer},
+		userinfo: &oidc.UserinfoHandler{Tokens: tokens, ClientConfig: h.ClientConfig, Users: users, SigningKey: &key.PublicKey, Issuer: h.Issuer, Emitter: telemetry.NoopEmitter{}},
+	}
+}
+
+func (f *statusFixture) issue(t *testing.T) (string, string, int) {
+	t.Helper()
+	verifier, _ := makeVerifierAndChallenge()
+	code := seededSession(f.token.Sessions, verifier)
+	req := tokenRequest(url.Values{"grant_type": {"authorization_code"}, "client_id": {"test-client"}, "code": {code}, "code_verifier": {verifier}})
+	if f.token.ClientConfig["test-client"].ClientType == "confidential" {
+		req.SetBasicAuth(url.QueryEscape("test-client"), url.QueryEscape(f.token.ClientConfig["test-client"].ClientSecret))
+	}
+	w := httptest.NewRecorder()
+	f.token.ServeHTTP(w, req)
+	if w.Code != http.StatusOK {
+		return "", "", w.Code
+	}
+	var body struct {
+		Access string `json:"access_token"`
+		ID     string `json:"id_token"`
+	}
+	if json.Unmarshal(w.Body.Bytes(), &body) != nil || body.Access == "" || body.ID == "" {
+		t.Fatal("invalid token response")
+	}
+	return body.Access, body.ID, w.Code
+}
+
+func (f *statusFixture) request(t *testing.T, raw, client, secret string, revoke bool, mutate func(*http.Request)) *httptest.ResponseRecorder {
+	t.Helper()
+	form := url.Values{"token": {raw}}
+	if secret == "" {
+		form.Set("client_id", client)
+	}
+	r := httptest.NewRequest(http.MethodPost, "/introspect", strings.NewReader(form.Encode()))
+	r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	if secret != "" {
+		r.SetBasicAuth(url.QueryEscape(client), url.QueryEscape(secret))
+	}
+	if mutate != nil {
+		mutate(r)
+	}
+	w := httptest.NewRecorder()
+	if revoke {
+		f.status.Revoke(w, r)
+	} else {
+		f.status.Introspect(w, r)
+	}
+	if w.Header().Get("Cache-Control") != "no-store" || w.Header().Get("Pragma") != "no-cache" {
+		t.Fatal("missing private response controls")
+	}
+	return w
+}
+
+func (f *statusFixture) introspect(t *testing.T, raw string) map[string]interface{} {
+	t.Helper()
+	w := f.request(t, raw, "test-client", f.token.ClientConfig["test-client"].ClientSecret, false, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("introspection status %d", w.Code)
+	}
+	var body map[string]interface{}
+	if json.Unmarshal(w.Body.Bytes(), &body) != nil {
+		t.Fatal("invalid introspection response")
+	}
+	return body
+}
+
+func (f *statusFixture) userinfoStatus(raw string) int {
+	w := httptest.NewRecorder()
+	f.userinfo.ServeHTTP(w, userinfoRequest(raw))
+	return w.Code
+}
+
+func TestTokenStatusActualIssueRevokeAndFreshGrant(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	first, id, code := f.issue(t)
+	if code != http.StatusOK {
+		t.Fatalf("issue status %d", code)
+	}
+	active := f.introspect(t, first)
+	if active["active"] != true || active["sub"] != "user-alice" || active["client_id"] != "test-client" || active["token_type"] != "Bearer" {
+		t.Fatal("wrong active-token metadata")
+	}
+	if _, present := parseJWTPayload(t, id)["jti"]; present {
+		t.Fatal("access-token lifecycle changed ID token")
+	}
+	if f.userinfoStatus(first) != http.StatusOK {
+		t.Fatal("issued token refused")
+	}
+	second, _, code := f.issue(t)
+	if code != http.StatusOK || first == second || active["jti"] == f.introspect(t, second)["jti"] {
+		t.Fatal("fresh grants must be distinct")
+	}
+	for i := 0; i < 2; i++ {
+		w := f.request(t, first, "test-client", "synthetic-status-only", true, nil)
+		if w.Code != http.StatusOK || w.Body.Len() != 0 {
+			t.Fatal("revocation must be empty idempotent success")
+		}
+	}
+	if got := f.introspect(t, first); got["active"] != false || len(got) != 1 {
+		t.Fatal("revoked metadata leaked or remained active")
+	}
+	if f.userinfoStatus(first) != http.StatusUnauthorized {
+		t.Fatal("revoked token still accepted by real UserInfo")
+	}
+	if f.introspect(t, second)["active"] != true || f.userinfoStatus(second) != http.StatusOK {
+		t.Fatal("revoking one grant affected another")
+	}
+	third, _, code := f.issue(t)
+	if code != http.StatusOK || f.introspect(t, third)["active"] != true || f.introspect(t, first)["active"] != false {
+		t.Fatal("fresh issuance reactivated a revoked grant")
+	}
+}
+
+func TestTokenStatusNoCrossClientOrIDTokenAuthority(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	raw, id, _ := f.issue(t)
+	for _, invalid := range []string{id, "unknown.synthetic.token", raw + "changed"} {
+		got := f.introspect(t, invalid)
+		if len(got) != 1 || got["active"] != false {
+			t.Fatal("non-access token disclosed metadata")
+		}
+		w := f.request(t, invalid, "test-client", "synthetic-status-only", true, nil)
+		if w.Code != http.StatusOK || w.Body.Len() != 0 {
+			t.Fatal("unknown revocation disclosed state")
+		}
+	}
+	w := f.request(t, raw, "other", "synthetic-other-only", false, nil)
+	if w.Code != http.StatusOK || strings.TrimSpace(w.Body.String()) != `{"active":false}` {
+		t.Fatal("other client read token")
+	}
+	w = f.request(t, raw, "other", "synthetic-other-only", true, nil)
+	if w.Code != http.StatusOK || f.introspect(t, raw)["active"] != true {
+		t.Fatal("other client revoked token")
+	}
+}
+
+func TestTokenStatusCapacityFailsIssuanceWithoutEvictingLiveToken(t *testing.T) {
+	f := newStatusFixture(t, 1)
+	raw, _, code := f.issue(t)
+	if code != http.StatusOK {
+		t.Fatal("first issuance failed")
+	}
+	if _, _, code = f.issue(t); code != http.StatusServiceUnavailable {
+		t.Fatalf("full store issue status %d", code)
+	}
+	if f.introspect(t, raw)["active"] != true {
+		t.Fatal("capacity evicted live authority")
+	}
+	f.request(t, raw, "test-client", "synthetic-status-only", true, nil)
+	if _, _, code = f.issue(t); code != http.StatusServiceUnavailable {
+		t.Fatal("revocation tombstone was evicted before expiry")
+	}
+}
+
+func TestTokenStatusRestartAndUnavailableStoreRefuse(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	raw, _, _ := f.issue(t)
+	empty, err := oidc.NewTokenStatusStore(8)
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.status.Tokens, f.userinfo.Tokens = empty, empty
+	if f.introspect(t, raw)["active"] != false || f.userinfoStatus(raw) != http.StatusUnauthorized {
+		t.Fatal("restart resurrected unknown token")
+	}
+	f.status.Tokens = nil
+	if w := f.request(t, raw, "test-client", "synthetic-status-only", false, nil); w.Code != http.StatusServiceUnavailable {
+		t.Fatal("missing store allowed online status")
+	}
+	// Offline JWT validity remains a separate legacy contract. Do not claim
+	// that adding an endpoint revokes tokens in consumers that never consult it.
+	f.userinfo.Tokens = nil
+	if f.userinfoStatus(raw) != http.StatusOK {
+		t.Fatal("legacy profile changed")
+	}
+}
+
+func TestTokenStatusRegistrationDriftAndDirectoryDisposition(t *testing.T) {
+	for _, change := range []string{"removed", "audience", "secret", "scopes", "lifetime", "suspended", "disabled", "user-removed"} {
+		t.Run(change, func(t *testing.T) {
+			f := newStatusFixture(t, 8)
+			raw, _, _ := f.issue(t)
+			switch change {
+			case "removed":
+				delete(f.token.ClientConfig, "test-client")
+			case "audience":
+				f.token.ClientConfig["test-client"].Audience = "different-resource"
+			case "secret":
+				f.token.ClientConfig["test-client"].ClientSecret = "replacement-synthetic-only"
+			case "scopes":
+				f.token.ClientConfig["test-client"].AllowedScopes = []string{"openid"}
+			case "lifetime":
+				f.token.ClientConfig["test-client"].TokenLifetime = time.Minute
+			case "suspended":
+				f.users.users["alice"].Groups = []string{"netkingdom-suspended"}
+			case "disabled":
+				f.users.users["alice"].Enabled = false
+			case "user-removed":
+				delete(f.users.users, "alice")
+			}
+			if f.userinfoStatus(raw) != http.StatusUnauthorized {
+				t.Fatal("UserInfo accepted changed authority")
+			}
+			if change != "removed" && f.introspect(t, raw)["active"] != false {
+				t.Fatal("introspection accepted changed authority")
+			}
+		})
+	}
+}
+
+func TestTokenStatusPublicClientMayRevokeButNotIntrospect(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	f.token.ClientConfig["test-client"].ClientType = "public"
+	f.token.ClientConfig["test-client"].ClientSecret = ""
+	raw, _, code := f.issue(t)
+	if code != http.StatusOK {
+		t.Fatal("public PKCE issue failed")
+	}
+	if w := f.request(t, raw, "test-client", "", false, nil); w.Code != http.StatusUnauthorized {
+		t.Fatal("public client enumerated status")
+	}
+	if w := f.request(t, raw, "test-client", "", true, nil); w.Code != http.StatusOK {
+		t.Fatal("public bearer revocation failed")
+	}
+	if f.userinfoStatus(raw) != http.StatusUnauthorized {
+		t.Fatal("public revocation not enforced")
+	}
+}
+
+func TestTokenStatusServiceGrantIsCurrentAndDistinct(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	client := f.token.ClientConfig["test-client"]
+	client.GrantTypes, client.ServiceSubject, client.Tenant = []string{"client_credentials"}, "service:status-fixture", "tenant:fixture"
+	issue := func() string {
+		r := tokenRequest(url.Values{"grant_type": {"client_credentials"}})
+		r.SetBasicAuth(url.QueryEscape(client.ClientID), url.QueryEscape(client.ClientSecret))
+		w := httptest.NewRecorder()
+		f.token.ServeHTTP(w, r)
+		if w.Code != http.StatusOK {
+			t.Fatalf("service issue status %d", w.Code)
+		}
+		var body struct {
+			Access string `json:"access_token"`
+		}
+		if json.Unmarshal(w.Body.Bytes(), &body) != nil || body.Access == "" {
+			t.Fatal("service response invalid")
+		}
+		return body.Access
+	}
+	first, second := issue(), issue()
+	if first == second || f.introspect(t, first)["active"] != true {
+		t.Fatal("service grants not distinct/current")
+	}
+	f.request(t, first, client.ClientID, client.ClientSecret, true, nil)
+	if f.introspect(t, first)["active"] != false || f.introspect(t, second)["active"] != true {
+		t.Fatal("service revocation not token-scoped")
+	}
+}
+
+func TestTokenStatusRejectsMalformedOrUnauthenticatedRequests(t *testing.T) {
+	for _, kind := range []string{"get", "query", "json", "duplicate-token", "oversize", "wrong-secret", "missing-auth", "duplicate-auth", "body-secret", "mismatched-client"} {
+		t.Run(kind, func(t *testing.T) {
+			f := newStatusFixture(t, 8)
+			raw, _, _ := f.issue(t)
+			mutate := func(r *http.Request) {
+				body := func(form url.Values) { r.Body = io.NopCloser(strings.NewReader(form.Encode())) }
+				switch kind {
+				case "get":
+					r.Method = http.MethodGet
+				case "query":
+					r.URL.RawQuery = "token=must-never-use-url"
+				case "json":
+					r.Header.Set("Content-Type", "application/json")
+				case "duplicate-token":
+					body(url.Values{"token": {raw, raw}})
+				case "oversize":
+					body(url.Values{"token": {strings.Repeat("x", 65537)}})
+				case "wrong-secret":
+					r.SetBasicAuth("test-client", "wrong-synthetic-secret")
+				case "missing-auth":
+					r.Header.Del("Authorization")
+				case "duplicate-auth":
+					r.Header.Add("Authorization", "Basic extra")
+				case "body-secret":
+					body(url.Values{"token": {raw}, "client_secret": {"unsupported"}})
+				case "mismatched-client":
+					body(url.Values{"token": {raw}, "client_id": {"other"}})
+				}
+			}
+			for _, revoke := range []bool{false, true} {
+				w := f.request(t, raw, "test-client", "synthetic-status-only", revoke, mutate)
+				if w.Code < 400 {
+					t.Fatal("malformed request accepted")
+				}
+			}
+			if f.introspect(t, raw)["active"] != true {
+				t.Fatal("refused request changed token")
+			}
+		})
+	}
+}
+
+type blockingStatusUsers struct {
+	*mockUserRepo
+	entered, release chan struct{}
+}
+
+func (u *blockingStatusUsers) LookupUser(ctx context.Context, name string) (*domain.User, error) {
+	close(u.entered)
+	select {
+	case <-u.release:
+		return u.mockUserRepo.LookupUser(ctx, name)
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+func TestTokenStatusRevocationDuringDirectoryLookupRefuses(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	raw, _, _ := f.issue(t)
+	users := &blockingStatusUsers{mockUserRepo: f.users, entered: make(chan struct{}), release: make(chan struct{})}
+	f.status.Users = users
+	done := make(chan *httptest.ResponseRecorder, 1)
+	go func() { done <- f.request(t, raw, "test-client", "synthetic-status-only", false, nil) }()
+	select {
+	case <-users.entered:
+	case <-time.After(3 * time.Second):
+		t.Fatal("directory lookup not entered")
+	}
+	f.request(t, raw, "test-client", "synthetic-status-only", true, nil)
+	close(users.release)
+	select {
+	case w := <-done:
+		if strings.TrimSpace(w.Body.String()) != `{"active":false}` {
+			t.Fatal("delayed lookup resurrected revoked token")
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatal("introspection did not finish")
+	}
+}

src/internal/server/oidc/token_status_transport_test.go

@@ -0,0 +1,121 @@
+package oidc_test
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestTokenStatusActualHTTPSFlowAndAuthenticationEncoding(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	f.token.ClientConfig["test-client"].ClientSecret = "synthetic + / colon: only"
+	mux := http.NewServeMux()
+	mux.Handle("/token", f.token)
+	mux.Handle("/userinfo", f.userinfo)
+	mux.HandleFunc("/introspect", f.status.Introspect)
+	mux.HandleFunc("/revoke", f.status.Revoke)
+	server := httptest.NewTLSServer(mux)
+	defer server.Close()
+	client := server.Client()
+	verifier, _ := makeVerifierAndChallenge()
+	code := seededSession(f.token.Sessions, verifier)
+	post := func(path string, form url.Values) (int, []byte) {
+		r, err := http.NewRequest(http.MethodPost, server.URL+path, strings.NewReader(form.Encode()))
+		if err != nil {
+			t.Fatal("request construction failed")
+		}
+		r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+		r.SetBasicAuth(url.QueryEscape("test-client"), url.QueryEscape(f.token.ClientConfig["test-client"].ClientSecret))
+		resp, err := client.Do(r)
+		if err != nil {
+			t.Fatal("HTTPS fixture transport failed")
+		}
+		defer resp.Body.Close()
+		body, err := io.ReadAll(io.LimitReader(resp.Body, 65537))
+		if err != nil || len(body) > 65536 {
+			t.Fatal("response read failed")
+		}
+		return resp.StatusCode, body
+	}
+	status, body := post("/token", url.Values{"grant_type": {"authorization_code"}, "client_id": {"test-client"}, "code": {code}, "code_verifier": {verifier}, "redirect_uri": {seededRedirectURI}})
+	var tokens struct {
+		Access string `json:"access_token"`
+	}
+	if status != http.StatusOK || json.Unmarshal(body, &tokens) != nil || tokens.Access == "" {
+		t.Fatal("actual HTTPS PKCE exchange failed")
+	}
+	// A misleading type hint must not hide a supported access token.
+	form := url.Values{"token": {tokens.Access}, "token_type_hint": {"refresh_token"}}
+	status, body = post("/introspect", form)
+	var metadata map[string]interface{}
+	if status != http.StatusOK || json.Unmarshal(body, &metadata) != nil || metadata["active"] != true {
+		t.Fatal("actual HTTPS introspection failed")
+	}
+	if status, body = post("/revoke", form); status != http.StatusOK || len(body) != 0 {
+		t.Fatal("actual HTTPS revocation failed")
+	}
+	status, body = post("/introspect", form)
+	if status != http.StatusOK || strings.TrimSpace(string(body)) != `{"active":false}` {
+		t.Fatal("revocation did not affect HTTPS introspection")
+	}
+	r, _ := http.NewRequest(http.MethodGet, server.URL+"/userinfo", nil)
+	r.Header.Set("Authorization", "Bearer "+tokens.Access)
+	resp, err := client.Do(r)
+	if err != nil {
+		t.Fatal("HTTPS UserInfo failed")
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusUnauthorized || resp.Header.Get("Cache-Control") != "no-store" {
+		t.Fatal("real UserInfo accepted or cached revoked bearer")
+	}
+}
+
+func TestTokenStatusRevocationDuringUserInfoLookupRefuses(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	raw, _, _ := f.issue(t)
+	users := &blockingStatusUsers{mockUserRepo: f.users, entered: make(chan struct{}), release: make(chan struct{})}
+	f.userinfo.Users = users
+	done := make(chan int, 1)
+	go func() { done <- f.userinfoStatus(raw) }()
+	select {
+	case <-users.entered:
+	case <-time.After(3 * time.Second):
+		t.Fatal("UserInfo did not enter directory lookup")
+	}
+	f.request(t, raw, "test-client", "synthetic-status-only", true, nil)
+	close(users.release)
+	select {
+	case code := <-done:
+		if code != http.StatusUnauthorized {
+			t.Fatal("delayed UserInfo lookup resurrected revoked token")
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatal("UserInfo did not finish")
+	}
+}
+
+func TestTokenStatusLegacyGrantHasNoStatusClaim(t *testing.T) {
+	f := newStatusFixture(t, 8)
+	f.token.Tokens = nil
+	raw, id, code := f.issue(t)
+	if code != http.StatusOK {
+		t.Fatal("legacy issue failed")
+	}
+	for _, token := range []string{raw, id} {
+		if _, present := parseJWTPayload(t, token)["jti"]; present {
+			t.Fatal("disabled token contract changed")
+		}
+	}
+	if f.introspect(t, raw)["active"] != false || f.userinfoStatus(raw) != http.StatusUnauthorized {
+		t.Fatal("unregistered legacy token gained online authority")
+	}
+	f.userinfo.Tokens = nil
+	if f.userinfoStatus(raw) != http.StatusOK {
+		t.Fatal("legacy token no longer accepted in legacy mode")
+	}
+}

src/internal/server/oidc/userinfo.go

@@ -22,15 +22,21 @@ import (
 // the user, and returns claims that are consistent with those in the ID token
 // for the same scope set.
 type UserinfoHandler struct {
-	Users      domain.UserRepository
-	SigningKey *rsa.PublicKey // used to verify the incoming access token
-	Issuer     string
-	Emitter    telemetry.Emitter
+	Users        domain.UserRepository
+	SigningKey   *rsa.PublicKey // used to verify the incoming access token
+	Issuer       string
+	Emitter      telemetry.Emitter
+	Tokens       *TokenStatusStore
+	ClientConfig map[string]*domain.Client
 }
 
 // ServeHTTP handles GET /userinfo.
 func (h *UserinfoHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
+	if h.Tokens != nil {
+		w.Header().Set("Cache-Control", "no-store")
+		w.Header().Set("Pragma", "no-cache")
+	}
 
 	// 1. Extract Bearer token.
 	tokenStr, ok := bearerToken(r)
@@ -46,6 +52,12 @@ func (h *UserinfoHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, `{"error":"invalid_token","description":"token validation failed"}`, http.StatusUnauthorized)
 		return
 	}
+	if h.Tokens != nil {
+		if _, active := h.Tokens.active(tokenStr, h.ClientConfig, time.Now()); !active {
+			http.Error(w, `{"error":"invalid_token"}`, http.StatusUnauthorized)
+			return
+		}
+	}
 
 	// 3. Extract sub claim (which is the username in our model).
 	sub, _ := claims["sub"].(string)
@@ -68,6 +80,12 @@ func (h *UserinfoHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, `{"error":"invalid_token","description":"subject is suspended"}`, http.StatusUnauthorized)
 		return
 	}
+	if h.Tokens != nil {
+		if _, active := h.Tokens.active(tokenStr, h.ClientConfig, time.Now()); !user.Enabled || !active {
+			http.Error(w, `{"error":"invalid_token"}`, http.StatusUnauthorized)
+			return
+		}
+	}
 
 	// 5. Build response claims filtered by the scopes embedded in the token.
 	scopeStr, _ := claims["scope"].(string)