diff --git a/app/controllers/oidc_controller.rb b/app/controllers/oidc_controller.rb
index cbea16c..5198472 100644
--- a/app/controllers/oidc_controller.rb
+++ b/app/controllers/oidc_controller.rb
@@ -30,7 +30,17 @@ class OidcController < ApplicationController
       id_token_signing_alg_values_supported: ["RS256"],
       scopes_supported: ["openid", "profile", "email", "groups", "offline_access"],
       token_endpoint_auth_methods_supported: ["client_secret_post", "client_secret_basic"],
-      claims_supported: ["sub", "email", "email_verified", "name", "preferred_username", "groups", "admin", "auth_time", "acr", "azp", "at_hash"],
+      claims_supported: [
+        "sub",              # Always included
+        "email",            # email scope
+        "email_verified",   # email scope
+        "name",             # profile scope
+        "preferred_username", # profile scope
+        "updated_at",       # profile scope
+        "groups"            # groups scope
+        # Note: Custom claims are also supported but not listed here
+        # ID-token-only claims (auth_time, acr, azp, at_hash, nonce) are not listed
+      ],
       code_challenge_methods_supported: ["plain", "S256"],
       backchannel_logout_supported: true,
       backchannel_logout_session_supported: true
@@ -657,26 +667,13 @@ class OidcController < ApplicationController
     end
 
     # Profile claims (only if 'profile' scope requested)
-    # Per OIDC Core spec section 5.4, all profile claims SHOULD be returned
+    # Per OIDC Core spec section 5.4, include available profile claims
+    # Only include claims we have data for - omit unknown claims rather than returning null
     if requested_scopes.include?("profile")
       # Use username if available, otherwise email as preferred_username
       claims[:preferred_username] = user.username.presence || user.email_address
       # Name: use stored name or fall back to email
       claims[:name] = user.name.presence || user.email_address
-
-      # Standard profile claims we don't store - set to nil (optional per spec)
-      claims[:given_name] = nil
-      claims[:family_name] = nil
-      claims[:middle_name] = nil
-      claims[:nickname] = nil
-      claims[:profile] = nil
-      claims[:picture] = nil
-      claims[:website] = nil
-      claims[:gender] = nil
-      claims[:birthdate] = nil
-      claims[:zoneinfo] = nil
-      claims[:locale] = nil
-
       # Time the user's information was last updated
       claims[:updated_at] = user.updated_at.to_i
     end
diff --git a/app/services/oidc_jwt_service.rb b/app/services/oidc_jwt_service.rb
index dfd0135..3415d63 100644
--- a/app/services/oidc_jwt_service.rb
+++ b/app/services/oidc_jwt_service.rb
@@ -23,17 +23,10 @@ class OidcJwtService
         iat: now
       }
 
-      # Email claims (only if 'email' scope requested)
-      if requested_scopes.include?("email")
-        payload[:email] = user.email_address
-        payload[:email_verified] = true
-      end
-
-      # Profile claims (only if 'profile' scope requested)
-      if requested_scopes.include?("profile")
-        payload[:preferred_username] = user.username.presence || user.email_address
-        payload[:name] = user.name.presence || user.email_address
-      end
+      # NOTE: Email and profile claims are NOT included in the ID token for authorization code flow
+      # Per OIDC Core spec §5.4, these claims should only be returned via the UserInfo endpoint
+      # For implicit flow (response_type=id_token), claims would be included here, but we only
+      # support authorization code flow, so these claims are omitted from the ID token.
 
       # Add nonce if provided (OIDC requires this for implicit flow)
       payload[:nonce] = nonce if nonce.present?
diff --git a/test/controllers/oidc_userinfo_controller_test.rb b/test/controllers/oidc_userinfo_controller_test.rb
index b7c4b4a..d6508b3 100644
--- a/test/controllers/oidc_userinfo_controller_test.rb
+++ b/test/controllers/oidc_userinfo_controller_test.rb
@@ -115,25 +115,10 @@ class OidcUserinfoControllerTest < ActionDispatch::IntegrationTest
     # Required claims
     assert json["sub"].present?
 
-    # All standard profile claims should be present (per OIDC Core spec section 5.4)
-    # Some may be null if we don't have the data, but the keys should exist
-    assert json.key?("name"), "Should include name claim"
-    assert json.key?("given_name"), "Should include given_name claim (may be null)"
-    assert json.key?("family_name"), "Should include family_name claim (may be null)"
-    assert json.key?("middle_name"), "Should include middle_name claim (may be null)"
-    assert json.key?("nickname"), "Should include nickname claim (may be null)"
-    assert json.key?("preferred_username"), "Should include preferred_username claim"
-    assert json.key?("profile"), "Should include profile claim (may be null)"
-    assert json.key?("picture"), "Should include picture claim (may be null)"
-    assert json.key?("website"), "Should include website claim (may be null)"
-    assert json.key?("gender"), "Should include gender claim (may be null)"
-    assert json.key?("birthdate"), "Should include birthdate claim (may be null)"
-    assert json.key?("zoneinfo"), "Should include zoneinfo claim (may be null)"
-    assert json.key?("locale"), "Should include locale claim (may be null)"
-    assert json.key?("updated_at"), "Should include updated_at claim"
-
-    # Verify preferred_username is using username or email
-    assert json["preferred_username"].present?, "preferred_username should have a value"
+    # Profile claims we support should be present
+    assert json["name"].present?, "Should include name with profile scope"
+    assert json["preferred_username"].present?, "Should include preferred_username with profile scope"
+    assert json["updated_at"].present?, "Should include updated_at with profile scope"
 
     # Email claims should NOT be present
     assert_nil json["email"], "Should not include email without email scope"