diff --git a/src/adapters/express.ts b/src/adapters/express.ts
index f5ab0100..c5482d0e 100644
--- a/src/adapters/express.ts
+++ b/src/adapters/express.ts
@@ -31,6 +31,8 @@ export function handleExpressError(e: unknown | OAuthException, res: Response):
     res.send({
       status: e.status,
       message: e.message,
+      error: e.errorType,
+      error_description: e.errorDescription ?? e.error,
     });
     return;
   }
diff --git a/src/adapters/fastify.ts b/src/adapters/fastify.ts
index cfaecd97..3d16df95 100644
--- a/src/adapters/fastify.ts
+++ b/src/adapters/fastify.ts
@@ -25,6 +25,8 @@ export function handleFastifyError(e: unknown | OAuthException, res: FastifyRepl
     res.status(e.status).send({
       status: e.status,
       message: e.message,
+      error: e.errorType,
+      error_description: e.errorDescription ?? e.error,
     });
     return;
   }