diff --git a/src/schemas/post.spec.ts b/src/schemas/post.spec.ts
index 5021f60..652f941 100644
--- a/src/schemas/post.spec.ts
+++ b/src/schemas/post.spec.ts
@@ -364,6 +364,7 @@ describe("post", () => {
     if (result.success) {
       throw new Error("Expected error");
     }
+
     expect(JSON.stringify(result.error)).toEqual(
       expect.stringMatching(/comment syntax error/),
     );
diff --git a/src/schemas/post.ts b/src/schemas/post.ts
index f386ee6..d3a33b3 100644
--- a/src/schemas/post.ts
+++ b/src/schemas/post.ts
@@ -34,7 +34,7 @@ export const post = z
         message: `Failed to parse post ${url}`,
         code: ZodIssueCode.custom,
         params: {
-          error,
+          error: error instanceof Error ? error.message : "Unknown error",
         },
       });
       return z.NEVER;