diff --git a/src/model/model.ts b/src/model/model.ts
index 81511ab..67963bd 100644
--- a/src/model/model.ts
+++ b/src/model/model.ts
@@ -193,12 +193,12 @@ export interface OAuth2CodeAdapter {
   /**
    * Get user ID from a code object
    */
-  getUserId: (code: OAuth2Code) => string;
+  getUserId: (code: OAuth2Code) => string | number;
 
   /**
    * Get client ID from a code object
    */
-  getClientId: (code: OAuth2Code) => string;
+  getClientId: (code: OAuth2Code) => string | number;
 
   /**
    * Get scope from a code object
@@ -252,17 +252,17 @@ export interface OAuth2RefreshTokenAdapter {
   /**
    * Get user ID from token
    */
-  getUserId: (code: OAuth2RefreshToken) => string;
+  getUserId: (token: OAuth2RefreshToken) => string | number;
 
   /**
    * Get client ID from token
    */
-  getClientId: (code: OAuth2RefreshToken) => string;
+  getClientId: (token: OAuth2RefreshToken) => string | number;
 
   /**
    * Get scope from token
    */
-  getScope: (code: OAuth2RefreshToken) => string;
+  getScope: (token: OAuth2RefreshToken) => string;
 }
 
 /**