agent_patch

diff --git a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-1-codex-mini/app/packages/zod/src/v4/classic/tests/error-utils.test.ts b/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
index f6b2d3e..29d7eec 100644
--- a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-1-codex-mini/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
+++ b/app/packages/zod/src/v4/classic/tests/error-utils.test.ts
@@ -416,6 +416,37 @@ test("z.treeifyError 2", () => {
   `);
 });
 
+test("z.treeifyError respects branded primitives", () => {
+  const schema = z.strictObject({
+    username: z.string().brand("Username"),
+  });
+  const result = schema.safeParse({
+    username: 123,
+  });
+  const err = z.treeifyError(result.error!);
+  expect(err).toMatchInlineSnapshot(`
+    {
+      "errors": [],
+      "properties": {
+        "username": {
+          "errors": [
+            "Invalid input: expected string, received number",
+          ],
+        },
+      },
+    }
+  `);
+
+  type ErrorTree = typeof err;
+  type IdentifierNode = NonNullable<ErrorTree["properties"]>["username"];
+  type HasProperties = IdentifierNode extends { properties: unknown } ? true : false;
+  type HasItems = IdentifierNode extends { items: unknown } ? true : false;
+
+  expectTypeOf<IdentifierNode>().toMatchTypeOf<{ errors: string[] } | undefined>();
+  expectTypeOf<HasProperties>().toEqualTypeOf<false>();
+  expectTypeOf<HasItems>().toEqualTypeOf<false>();
+});
+
 test("z.prettifyError", () => {
   expect(z.prettifyError(result.error!)).toMatchInlineSnapshot(`
     "✖ Unrecognized key: "extra"
diff --git a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-1-codex-mini/app/packages/zod/src/v4/core/errors.ts b/app/packages/zod/src/v4/core/errors.ts
index 699c81f..28ea66b 100644
--- a/tmp/agent-patch-flux-pr-4843.1-of-1.2026-02-27__21-30-28__gpt-5-1-codex-mini/app/packages/zod/src/v4/core/errors.ts
+++ b/app/packages/zod/src/v4/core/errors.ts
@@ -1,5 +1,5 @@
 import type { $ZodCheck, $ZodStringFormats } from "./checks.js";
-import { $constructor } from "./core.js";
+import { $brand, $constructor } from "./core.js";
 import type { $ZodType } from "./schemas.js";
 import * as util from "./util.js";
 
@@ -295,14 +295,22 @@ export function formatError<T>(error: $ZodError, _mapper?: any) {
   return fieldErrors;
 }
 
-export type $ZodErrorTree<T, U = string> = T extends [any, ...any[]]
-  ? { errors: U[]; items?: { [K in keyof T]?: $ZodErrorTree<T[K], U> } }
+type $RemoveBrand<T> = T extends infer U
+  ? U extends { [k in typeof $brand]: unknown }
+    ? Omit<U, typeof $brand>
+    : U
+  : never;
+
+type $ZodErrorTreeInternal<T, U = string> = T extends [any, ...any[]]
+  ? { errors: U[]; items?: { [K in keyof T]?: $ZodErrorTreeInternal<$RemoveBrand<T[K]>, U> } }
   : T extends any[]
-    ? { errors: U[]; items?: Array<$ZodErrorTree<T[number], U>> }
+    ? { errors: U[]; items?: Array<$ZodErrorTreeInternal<$RemoveBrand<T[number]>, U>> }
     : T extends object
-      ? { errors: U[]; properties?: { [K in keyof T]?: $ZodErrorTree<T[K], U> } }
+      ? { errors: U[]; properties?: { [K in keyof T]?: $ZodErrorTreeInternal<$RemoveBrand<T[K]>, U> } }
       : { errors: U[] };
 
+export type $ZodErrorTree<T, U = string> = $ZodErrorTreeInternal<$RemoveBrand<T>, U>;
+
 export function treeifyError<T>(error: $ZodError<T>): $ZodErrorTree<T>;
 export function treeifyError<T, U>(error: $ZodError<T>, mapper?: (issue: $ZodIssue) => U): $ZodErrorTree<T, U>;
 export function treeifyError<T>(error: $ZodError, _mapper?: any) {