diff --git a/fastify.d.ts b/fastify.d.ts
index bc9eea7731d..787d9326fbf 100644
--- a/fastify.d.ts
+++ b/fastify.d.ts
@@ -183,7 +183,7 @@ type TrustProxyFunction = (address: string, hop: number) => boolean
 declare module '@fastify/error' {
   interface FastifyError {
     validation?: ValidationResult[];
-    validationContext?: string;
+    validationContext?: "body" | "headers" | "parameters" | "querystring";
   }
 }